Forensic chemistry is unique among chemical sciences in that its research, practice, and presentation must meet the needs of both the scientific and the legal communities. As such, forensic chemistry research is applied and derivative by nature and design, and it emphasizes metrology (the science of measurement) and validation. Forensic chemistry has moved away from its analytical roots and is incorporating a broader spectrum of chemical sciences. Existing forensic practices are being revisited as the purview of forensic chemistry extends outward from drug analysis and toxicology into such diverse areas as combustion chemistry, materials science, and pattern evidence.

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... Each strand of cotton fiber was observed as highly convoluted and twisted cotton fiber (Figure 4a). Cotton fiber is a natural fiber composed mainly of cellulose that contain hydroxyl (-OH) groups ( Figure 5) [18]. In cotton cloth, the fiber matrix is capable of retaining the explosive analytes via iondipole and dipole-dipole interactions. ...

... Structural formula of cellulose[18]. ...

... Sites where analyte can interact with cellulose fibers of cotton cloth: (1) on the surface, (2) internally,(3) within the wall of fiber and (4) within spaces between fibers[18]. ...

Increased terrorist activities around the Asian region have resulted in the need for improved analytical techniques in forensic analysis. High explosive residues from post-blast clothing are often encountered as physical evidence submitted to a forensic laboratory. Therefore, this study was initiated to detect high explosives residues of cyclotrimethylenetrinitramine (RDX) and pentaerythritoltetranitrate (PETN) on selected cloth in this study. Cotton swabbing technique was employed as a simple and rapid method in recovering analytes from the sample matrix. Analytes were analyzed using Griess spot test, TLC and HPLC. TLC separation employed toluene-ethyl acetate (9:1) as a good solvent system. Reversed phase HPLC separation employed acetonitrile-water (65:35) as the mobile phase and analytes detected using a programmed wavelength. RDX was detected at 235 nm for the first 3.5 min and then switched to 215 nm for PETN. Limits of detection (LODs) of analytes were in the low ppm range (0.05 ppm for RDX and 0.25 ppm for PETN). Analyte recovery studies revealed that the type of cloth has a profound effect on the extraction efficiency. Analytes were recovered better for nylon as compared to cotton cloth. However, no analytes could be recovered from denim cloth. For post-blast samples, only RDX was detected in low concentration for both nylon and cotton cloth.

... 2 Thus, the detection and identication of the LFPs is an indispensable strategy in individual credential and forensic science. 3 Commonly, LFPs are developed using methods such as powder (metallic, magnetic, or uorescent powder) dusting, 4 chemical fumes (iodine fuming, cyanoacrylate fuming) 5 and the multi-metal deposition method (MMD). However, these traditional techniques are inevitably associated with serious problems in developing latent ngermarks, such as high toxicity, low detection sensitivity, and high background interference. ...

... NIR-LP concentration: 0.25 mM, the water fraction was 60% (B), 70% (C) and 80% (D), respectively. (E) Fluorescence images of LFPs showing level 2 details including lake (1) and bifurcation(2)(3)(4)(5). All fluorescent images were excited with a 365 nm UV lamp. ...

In this paper, a facile near infrared (NIR, 650-900 nm) probe 4-dimethylamino-2′-hydroxychalcone (NIR-LP) based on the excited state intramolecular proton transfer (ESIPT)-aggregation induced emission (AIE) processes for the detection of the latent fingerprints (LFPs) was developed for the first time. The probe can distinguish the fresh LFPs, but also recognize the aged (10 days) LFPs.

... The absorption of Allura Red was measured quantitively in COC chips with optical path lengths of 2, 3, and 4 mm, respectively. The maximum measurement on-chip and off-chip (cuvette setup) was present at 504 nm, which was in accordance with the information from the supplier [57]. A 0.2 mM stock solution of Allura Red was prepared, and a dilution series from this stock solution was prepared to obtain concentrations of 6 µM, 10 µM, 20 µM, 30 µM, 40 µM, and 50 µM. ...

... The molar absorptivity was determined for both the on-chip and off-chip measurements. With the cuvette, a molar absorptivity of 22,047 M −1 cm −1 was calculated, which is in accordance with the specifications of the supplier (≥20,000 M −1 cm −1 ) [57]. For chips A, B, and C, values of 28,835 M −1 cm −1 , 21,406 M −1 cm −1 , and 23,845 M −1 cm −1 were obtained, respectively. ...

Microfluidic devices offer important benefits for forensic applications, in particular for fast tests at a crime scene. A large portion of forensic applications require microfluidic chip material to show compatibility with biochemical reactions (such as amplification reactions), and to have high transparency in the visible region and high chemical resistance. Also, preferably, manufacturing should be simple. The characteristic properties of cyclic olefin copolymer (COC) fulfills these requirements and offers new opportunities for the development of new forensic tests. In this work, the versatility of COC as material for lab-on-a-chip (LOC) systems in forensic applications has been explored by realizing two proof-of-principle devices. Chemical resistance and optical transparency were investigated for the development of an on-chip presumptive color test to indicate the presence of an illicit substance through applying absorption spectroscopy. Furthermore, the compatibility of COC with a DNA amplification reaction was verified by performing an on-chip multiple displacement amplification (MDA) reaction.

... Colorimetric methods for the detection of narcotics have been developed and provide rapid detection in the field. 15, 16 However, these presumptive tests are subject to screener interpretation of the resulting color(s) and require onsite reagent mixing. ...

  • Thomas P Forbes Thomas P Forbes
  • Marcela Najarro

The discriminative potential of an ion mobility spectrometer (IMS) for trace detection of illicit narcotics relative to environmental background was investigated with a receiver operating characteristic (ROC) curve framework. The IMS response of cocaine, heroin, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), and Δ(9)-tetrahydro-cannabinol (THC) was evaluated against environmental background levels derived from the screening of incoming delivery vehicles at a federal facility. Over 20 000 samples were collected over a multiyear period under two distinct sets of instrument operating conditions, a baseline mode and an increased desorption/drift tube temperature and sampling time mode. ROC curves provided a quantifiable representation of the interplay between sensitivity (true positive rate, TPR) and specificity (1 - false positive rate, FPR). A TPR of 90% and minimized FPR were targeted as the detection limits of IMS for the selected narcotics. MDMA, THC, and cocaine demonstrated single nanogram sensitivity at 90% TPR and <10% FPR, with improvements to both MDMA and cocaine in the elevated temperature/increased sampling mode. Detection limits in the tens of nanograms with poor specificity (FPR ≈ 20%) were observed for methamphetamine and heroin under baseline conditions. However, elevating the temperature reduced the background in the methamphetamine window, drastically improving its response (90% TPR and 3.8% FPR at 1 ng). On the contrary, the altered mode conditions increased the level of background for THC and heroin, partially offsetting observed enhancements to desorption. The presented framework demonstrated the significant effect environmental background distributions have on sensitivity and specificity.

... Mass spectrometry is a necessity when it comes to structural elucidation and it is used in almost every analytical laboratory. Since its introduction 162 it has been widely used in a wide range of areas, for instance, in forensic analysis 163 , pharmaceutical analysis 164,165 , chemical analysis, environmental analysis 166 and geological analysis. Mass spectrometry is a powerful tool that is used to quantify, qualify and identify both known and unknown solutes. ...

... Introducing scientific evidence in a court of law via the use of expert testimony is only possible if both the evidence and testimony have been evaluated for reliability and validity by the presiding judge, a precedent that was established in 1993 by the landmark US Supreme Court case Daubert versus Merrell Dow Pharmaceuticals, Inc. (Ehleringer and Matheson, 2010). When considering the admission of scientific evidence, a judge must consider several aspects of the evidence including the general acceptance of the scientific approach, its testability, its level of peer review, the known error rate of the analytical method, and whether or not standards exist for data evaluation (Bell, 2009). Several features of the good scientific methods practiced by isotope geochemists make isotope data ideally suited for this scrutiny, including the standardized handling of samples, use of peer-reviewed preparation protocols and analytical methods, and established models for applying statistics and interpreting data. ...

Stable isotope analysis has a lengthy application history in the fields of biology, ecology, and geology but its application in forensic investigations is relatively new. A recent report by the National Research Council on the strength of the forensic sciences in the United States highlighted areas of weakness, including the lack of a tested scientific foundation for many of the analytical techniques used in examinations. Stable isotope analysis has a strong scientific foundation developed in the academic community and could thus play a major role in the forensic community as a powerful tool in the investigator's toolbox.This chapter presents a framework for applying the stable isotope analysis techniques commonly employed by isotope geochemists in forensics settings. The utility of this framework lies in its ability to address a range of questions from relatively simple sample comparisons to more complex region or origin predictions. The forensic application of stable isotope analysis within this framework is discussed at both a nonspatial and spatial scale, examples of applications include the analysis of nonorganic and organic materials. The chapter concludes with a discussion detailing how the stable isotope analysis techniques developed in scientific settings can be extremely useful in legal settings as well.

... On the basis of student interest, additional topics and research publications were introduced. The course material was assembled from a variety of sources, including two textbooks (Bell, 2012;Butler, 2010), online resources, and research articles. ...

  • Sulekha Coticone Sulekha Coticone
  • Lora Van Houten

A special topics course combining two relevant and contemporary themes (forensic DNA analysis and illicit drug detection) was developed to stimulate student enthusiasm and enhance understanding of forensic science. Building on the interest of popular television shows such as CSI and Breaking Bad, this course connects essential concepts in biochemistry, genetics, molecular biology, organic chemistry, and general chemistry with criminal justice studies to kindle student interest using the forensic science theme. Available to students in criminal justice or natural science majors, the forensic science theme is the focus as students participate in interdisciplinary activities and discussions while exploring fundamental principles used to solve crimes. Requiring critical thinking and problem-solving skills, the collaboration of students of different academic focus leads to the debunking of myths surrounding both police and forensic scientists, while developing an awareness of how law enforcement and scientists work together in reality.

... This technique enables rapid sample preparation in the laboratory and even on-site for both volatile and nonvolatile compounds [18]. SPME requires little or no solvents in which the fiber is immersed in case of a liquid sample or exposed to the headspace above a solid or liquid sample [30,31]. The SPME fiber is then inserted into the injection port of a gas or liquid chromatograph, where the extracted analytes are desorbed and then determined [32,33]. ...

The identification of ignitable liquids is very important and challenging aspect in arson crime investigations. The detection of gasoline and diesel fuel components using solid phase micro-extraction prior to gas chromatography–mass spectrometry for the forensic analysis of fire debris has been carried out. Previous works show that the absorption characteristics of the substrate are one of the most important factors in determining the evaporation rate of the accelerants. In order to determine the presence of the fuel residues, four of the most common substrate materials were tested in this work; wool, cotton, silk and polyester. The obtained results indicate that both gasoline and diesel fuel accelerants persisted longer on wool and silk than on the other selected substrates. Such information illustrates the influence of fuel persistence times after extinguishing and the best materials to be scanned for ignitable liquids at the fire scene.

... Various situations exist in detection and identification of explosives in forensic cases. These may include improvised explosive devices, explosive residues at crime scenes, suspect shipments, and screening of hidden explosives carried by travelers on airlines [4,5]. The role of forensic experts pertain to identification and quantification of the explosive substance used, reconstructing the explosive device and comparing component of the explosive device with the related materials recovered from the possession or premises of the suspects thereby providing scientific evidence before the court of law. ...

  • Professor T. Nataraja Moorthy Professor T. Nataraja Moorthy

An explosion, whether accidental or intentional, typically results in serious damage to property and harm to people. The investigation of explosion has a long history in forensic science and covers incidents ranging from accidents in home or workplace to major terrorist attack. One of the most important tasks requiring the set of skills that only the forensic scientists possess is the preliminary identification and quantification of the explosive substance used in an incident. This determination can provide important information early on for the investigator and may play a major role in the direction the investigation will take. Evidence of an explosion may take the form of a crater or other damage which may provide some information facilitating and estimating the mass of explosive material used. The size of the crater is an important evident for the blast occurrence and the size vary depending upon the quantity and the type of explosive used. In this paper, a numerical study on craters formed by explosive loads on soil surface is presented. This pilot study, the first of kind in Malaysia to study the relationship between the crater parameter and quantity of explosive used. Considering the realistic crime scenarios, seven test charges (IED) loaded with different type and quantity of energetic materials representing high and low explosive packed in different types of confinement were used in the blasting exercise and presented the findings. The study was conducted at Tapah, Perak in collaboration with Royal Malaysian Police Force.

... Therefore, the detection of TNT has attracted much attention due to these environmental and health related concerns. On the other hand, the identification of its post explosive residues in forensic chemistry is also needed for use as a guideline to help narrow any investigation associated with securities [2]. ...

  • Saluma Samanman Saluma Samanman
  • N Masoh
  • Y Salah
  • K Phumivanichakit

A simple operating colorimetric sensor for trinitrotoluene (TNT) determination using a commercial scanner as a captured image was designed. The sensor is based on the chemical reaction between TNT and sodium hydroxide reagent to produce the color change within 96 well plates, which observed finally, recorded using a commercial scanner. The intensity of the color change increased with increase in TNT concentration and could easily quantify the concentration of TNT by digital image analysis using the Image J free software. Under optimum conditions, the sensor provided a linear dynamic range between 0.20 and 1.00 mg mL⁻¹(r = 0.9921) with a limit of detection of 0.10± 0.01 mg mL⁻¹. The relative standard deviation for eight experiments for the sensitivity was 3.8%. When applied for the analysis of TNT in two soil extract samples, the concentrations were found to be non-detectable to 0.26±0.04 mg mL⁻¹. The obtained recovery values (93-95%) were acceptable for soil samples tested.

... Use of performance enhancing drugs by athletes in sports is under increasing investigation. The isotopic ratio of 14 C= 13 C is routinely used to test banned substances in urine and blood of athletes (Bell, 2009;Zhang et al., 2014). Detection of "designer" drugs (Peters et al., 2010;Thevis, 2010), like tetrahydrogestinone, using IRMS with isotopically labeled stable isotopes at trace levels (<parts per trillion) in urine and blood has been demonstrated (Handelsman, 2004;Touber et al., 2007). ...

Mass spectrometry (MS) is widely regarded as the most sensitive and specific general purpose analytical technique. More than a century has passed for MS since the ground-breaking work of Nobel laureate Sir Joseph John Thomson in 1913. This Colloquium aims to (1) give an historical overview of the major instrumentation achievements that have driven mass spectrometry forward in the past century, including those leading up to the initial work of Thomson, (2) provide the nonspecialist with an introduction to MS, and (3) highlight some key applications of MS and explore the current and future trends. Because of the vastness of the subject area and quality of the manifold research efforts that have been undertaken over the last 100 years, which have contributed to the foundations and subsequent advances in mass spectrometry, it should be understood that not all of the key contributions may have been included in this Colloquium. Mass spectrometry has embraced a multitude of scientific disciplines and to recognize all of the achievements is an impossible task, such has been the diverse impact of this invaluable technique. Scientific progress is usually made via the cumulative effort of a large number of researchers; the achievements reported herein are only a representation of that effort.

... This generates the free-base form of cocaine,w hich comprises ap etrified mass,u sually yellowish brown, popularly known as "crack".T he latter form is poorlys oluble in water, but volatilizes easilyu pon heating (95 8C), so addicts can smokei ti ni mprovised pipes.T he word "crack" derives from the characteristic noise the rocksm ake when broken down by smoking. Thei nitial effects of cocaine on the body are euphoria, excitement, insomnia, and appetite suppression, because it acts on the central nervous system [2][3][4]. ...

Chemically modified screen printed electrodes (CM-SPE) using [UO2(4-MeOSalen)(H2O)] ⋅ H2O films were employed in the voltammetric determination of cocaine. The chemical modification was performed by dip coating electrode surfaces (carbon, gold, and platinum) with methanolic solution containing the Schiff base complex with subsequent drying step at room temperature. The optimized amount of the chemical modifier over the working electrode was found to be 2.39 µg mm−2 (geometric area). The voltammetric measurements were carried out in 50 : 50 v/v methanol:water solution containing 0.05 mol L−1 KCl and 0.1 mol L−1 LiCl as a supporting electrolyte without oxygen elimination by inert gas flow. The best results were obtained with carbon electrodes. Cocaine exhibits a well defined irreversible anodic peak current (ipa) at a potential (Epa) of 0.85 V vs Ag/AgCl. The current is directly proportional to the drug concentration. An optimal accumulation potential (Eprec), and time (tprec) of −0.80 V (vs Ag/AgCl), and 120 s, respectively, were determined. The linear dependence of ipa with square root of scan rate (υ) indicates that the mass transport at the electrode surface is controlled by diffusion. An optimized scan rate of 100 mV s−1 was obtained for analytical purposes. A limit of detection (LOD) and limit of quantification (LOQ) in 110 and 390 µmol L−1, respectively, with intra and inter-day repeatability of 2.61 % and 3.77 %, respectively, were obtained. In interference studies the proposed method demonstrated high specificity for cocaine in the presence of morphine and 3,4-methylenedioxymethanphetamine. The above results demonstrate that this method provides a fast and low cost procedure for determination of cocaine in trace levels.

... The vapour pressure of RDX is around 4.4 × 10 −7 Pa at 25°C, making vapour detection very difficult. 39,40 In this work, we use silver nanocubes (AgNCs) as a highly sensitive SERS substrate with very low limit-of-detection (LOD). We detect ultra-trace concentrations of explosives in the femtomolar range (10 −15 M) in solution and vapour, as well as a model analyte, Rhodamine-6G (Rh-6G), with excellent enhancement factors (>10 9 ). ...

Surface-enhanced Raman spectroscopy (SERS) has been widely utilised as a sensitive analytical technique for the detection of trace levels of organic molecules. The detection of organic compounds in the gas phase is particularly challenging due to the low concentration of adsorbed molecules on the surface of the SERS substrate. This is particularly the case of explosive materials, which typically have very low vapour pressures, limiting the use of SERS for their identification. In this work, silver nanocubes (AgNCs) were developed as a highly sensitive SERS substrate with very low limit-of-detection (LOD) for explosive materials down to the femtomolar (10⁻¹⁵ M) range. Unlike typical gold-based nanostructures, the AgNCs were found suitable for the detection of both aromatic and aliphatic explosives, enabling detection with high specificity at low concentration. SERS studies were first carried out using a model analyte, Rhodamine-6G (Rh-6G), as a probe molecule. The SERS enhancement factor was estimated as 8.71×10¹⁰ in this case. Further studies involved femtomolar concentrations of 2,4-dinitrotoluene (DNT) and nanomolar concentrations of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), as well as vapour phase detection of DNT.

... Forensic sciences [2][3][4] concern the application of scientific knowledge to legal problems and they are vital tools in any legal proceeding. The forensic sciences, including forensic chemistry [5][6][7][8], forensic biology [9,10], forensic anthropology [11], forensic medicine [12], forensic materials science [13,14], forensic engineering [15], computational forensics [16], etc., are broadly used to resolve civil disputes, to justly enforce criminal laws and government regulations, and to protect public health. ...

... In her review, Bell focuses on very important aspects of the analysis that must be followed in order to obtain such reliable and reproducible results. 1 Castillo-Peinado and de Castro discuss in their review the application of analytical chemistry to forensic analysis focusing on the different types of samples, 2 while Peter Gill published a book in 2014 regarding the impact of incorrectly assessing evidence. 3 Brettell, together with co-workers, published a series of biannual reviews from 1983 until 2011 in Analytical Chemistry, all were entitled Forensic Science and each contained reports of a variety of different analyses. ...

Forensic chemistry is the application of analytical chemistry to forensic analysis and is today one of the hot topics in the scientific literature as it can provide valuable information regarding crimes that have been committed and assist in their resolution. The literature in the field of forensic chemistry has been exponentially growing and covers several different subjects. This review discusses works published between 2013 and 2017 regarding portable or potentially portable devices (such as electrochemical sensors), field tests and intelligent devices that can be used in different areas of forensic chemistry and covers the following subjects: explosives, gunshot residues (GSR), liquid fuels, illicit drugs, beverages, alternative biological fluids and agrochemicals.

... As such, it provides a great deal of truth to many legal proceedings. The forensic sciences -forensic chemistry [9,10,32,42], forensic biology [51,72], forensic anthropology [15], forensic medicine [62], forensic materials science [47,48], forensic engineering [59], computational forensics [50], among others -are broadly used to resolve civil disputes, to justify and enforce criminal laws and government regulations, and to protect public health. It should be kept in mind, however, that forensic analysis is strongly controlled by the legal constraints which affect both the work implementation and the results [38]. ...

Biochemical analysis of biological substances found at a crime scene is an important aspect of forensic investigations, where the objective is to determine the identification of crime victims and suspects/persons-of-interest. One particular biochemistry/molecular biology-based area of interest in forensic analysis is forensic serology; this area focuses on the complex task of gathering information regarding the type, age, ethnicity, and/or gender of the sample originator from the biological fluids (blood, saliva, etc.) found at a crime scene. In this review, we cover various studies involving biocomputing techniques used for the analysis of biological samples – namely blood – in different forensic applications. The studies covered include the differentiation of gender and ethnicity using a biocomputing system that produces a binary result, as well as the determination of blood spot age. Each of the applications showcased in this review produces sometimes ambiguous results that would normally pose major problems for a study, however, the addition of biocomputing logic provides an extra level of certainty and clarity. We hope to convey the advantages of utilizing biocomputing methods in various forms of forensic analysis.

... Other review articles provide a more comprehensive and objective discussion of research articles in different areas of forensic chemistry (2,3). This review intends to provide an unbiased but critical discussion of the status of forensic mass spectrometry (MS) research, and not at all an encyclopedic coverage of all the papers in the field. ...

Developments in forensic mass spectrometry tend to follow, rather than lead, the developments in other disciplines. Techniques of great forensic utility or potential born independently of forensic applications include ambient ionization, imaging mass spectrometry, isotope ratio mass spectrometry, portable mass spectrometers, and hyphenated chromatography-mass spectrometry instruments, to name a few. Forensic science has the potential to benefit enormously from developments that are funded by other means, if only the infrastructure and personnel existed to adopt, validate, and implement the new technologies into casework. Perhaps one unique area in which forensic science is at the cutting edge is in the area of chemometrics and the determination of likelihood ratios for the evaluation of the weight of evidence. Such statistical techniques have been developed most extensively for ignitable-liquid residue analyses and isotope ratio analysis. This review attempts to capture the trends, motivating forces, and likely impact of developing areas of forensic mass spectrometry, with the caveat that none of this research is likely to have any real impact unless: (a) The instruments developed are turned into robust black boxes with red and green lights for positives and negatives, respectively, or (b) there are PhD graduates in the workforce who can help adopt these sophisticated techniques. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 8 is June 15, 2015. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.

... Use of performance enhancing drugs by athletes in sports is under increasing investigation. The isotopic ratio of 14 C= 13 C is routinely used to test banned substances in urine and blood of athletes (Bell, 2009;Zhang et al., 2014). Detection of "designer" drugs (Peters et al., 2010;Thevis, 2010), like tetrahydrogestinone, using IRMS with isotopically labeled stable isotopes at trace levels (<parts per trillion) in urine and blood has been demonstrated (Handelsman, 2004;Touber et al., 2007). ...

  • Fred Jjunju Fred Jjunju

Mass spectrometry (MS) is widely regarded as the most sensitive and specific general purpose analytical technique. More than a century has passed for MS since the ground-breaking work of Nobel laureate Sir Joseph John Thomson in 1913. This Colloquium aims to (1) give an historical overview of the major instrumentation achievements that have driven mass spectrometry forward in the past century, including those leading up to the initial work of Thomson, (2) provide the nonspecialist with an introduction to MS, and (3) highlight some key applications of MS and explore the current and future trends. Because of the vastness of the subject area and quality of the manifold research efforts that have been undertaken over the last 100 years, which have contributed to the foundations and subsequent advances in mass spectrometry, it should be understood that not all of the key contributions may have been included in this Colloquium. Mass spectrometry has embraced a multitude of scientific disciplines and to recognize all of the achievements is an impossible task, such has been the diverse impact of this invaluable technique. Scientific progress is usually made via the cumulative effort of a large number of researchers; the achievements reported herein are only a representation of that effort.

... This test consists in extracting cannabinoids with organic solvents such as hexane or methanol and adding the Fast Blue B salt C 14 H 12 Cl 2 N 4 O 2 .ZnCl 2 to the resulting solution. 8 A coupling reaction between Δ 9 -THC and other cannabinoids with Fast Blue B salt generates a deep red or purple chromophore with the active ingredients of the substance of forensic interest. ...

Marijuana is a widely consumed illicit drug. Therefore, drug dealers have sought new ways to mask its forensic (spot test) analysis. In this article we describe a methodology for delta-9-tetrahydrocannabinol (Delta(9)-THC) detection by square-wave voltammetric (SWV) analysis in organic medium (N,N-dimethylformamide) using tetrabutylammonium tetrafluoroborate (TBATFB) as supporting electrolyte, and glassy carbon and platinum disc as working electrode. Applying a potential of -0.5 +/- 0.01 V vs. Ag/AgCl, KCl(sat), we detected a well-defined anodic peak current after the pre-concentration step; Delta(9)-THC detection presented linear dependence at concentrations ranging from 1.0 x 10(-9) mol L-1 to 2.2 x 10(-8) mol L-1, with a linear correlation coefficient 0.999 and a detection limit of 6.2 x 10(-10) mol L-1, using the glassy carbon disc working electrode. These results confirm that optimized SWV technique using glassy carbon disc working electrode enables qualitative analysis of Delta(9)-THC at concentrations higher than 1.0 nmol L-1.

... The solid-phase microextraction (SPME) was invented by Pawliszyn in the early 1990s [16] . It is a much simpler method that uses no pre-chemistry or solvents in which a phase-coated fused silica fibre is exposed to the headspace of the sample [17][18] . Eric S et.al [19] , reported the effectiveness of headspace SPME as a solvent-free sampling technique for the recovery of accelerants. ...

In this study, the controlled burn experiments of carpets with and without gasoline in this study and commonly encountered substrates produced complex chromatograms producing peaks that were identified by mass spectrometry and comparison with reference standards and each other. The result shown that many of the compounds frequently encountered as a result of either combustion products or pyrolysis products of carpets detected in fresh gasoline as well. These compounds as background interferences that detect weather the gasoline exist in carpet combustion products or not.

... The interaction between an ink and a paper substrate, especially printing inks, has been covered in the literature from different standpoints and applications [16][17][18][19][20]. It is a complex process, where physical and chemical reactions take place, such as evaporation of volatiles, polymerization, oxidation, cross-linking and even paper corrosion [21]. Concerning writing pens, when an ink line is applied, it disperses throughout the paper and is absorbed into it. ...

  • André Braz
  • Carmen García Ruiz
  • Maria López-López Maria López-López

This manuscript presents a preliminary investigation on the applicability of Raman imaging for non-destructive and rapid analysis of blue crossing ink lines. The MCR method was used to facilitate visualization of the distribution of inks of the same colour and the most predominant Raman signature at the crossing was used to interpret the order of application of inks. Different pen ink types, different times separating the application of the two ink lines and different paper substrates were used. From the 90 Raman images examined, the correct order of application was determined in more than 60 % by direct observation. The remainder cases were not as clear due to the uneven distribution of inks and the empty spaces similar to a net-like pattern observed at the crossing. This pattern was possibly caused by physical impediments (the first ink applied acting as a physical barrier) or chemical impediments (the two inks did not stick). Such impediments were more strongly observed in the crossings involving the Uniball Eye pen ink, causing the complete skipping of this ink line. Moreover, most crossings showed some mixing between the two inks and it was more accentuated when the times separating the application of the inks were shorter, since the ink was fresher. The use of white or certificate papers did not seem to influence in the inks distribution nor determining the order of the inks. Although this study provided useful insights regarding crossing ink lines, future statistic studies may be helpful for more objective examinations.

... Several arson researches have been explored using SPME for the extraction of volatile organic accelerants from fire debris [25][26][27][28][29][30][31][32][33][34]. SPME is a powerful extraction technique, it consists of a phase coated fused silica fiber, and the fiber is coating with an immobilized polymer that exposed to the headspace of the sample [35,36]. The analytes are extracted from the headspace by absorption into the polymer coated onto a quartz fiber that is housed within a needle similar to a syringe needle. ...

The analysis of traces ignitable liquids on a burned carpet could provide information to a forensic investigation. While the research on this field is still limited, this study illustrates the capabilities of the solid-phase microextraction coupled with gas chromatography-mass spectrometry to detect and identify gasoline residue from fire debris. The technique proved to be rapid, simple and efficient; it does not require specific skills or solvents for the extraction. The obtained results indicate that the amount of fuel used to ignite the carpet samples and a carpet thickness, play an important role on the presence and survival of the gasoline residues. This depends on the adsorption capacity of the burned carpet, where it is preferred to take samples from thin carpets rather than thick one, i.e., gasoline traces were detected up to 5 h, above carpet of 5mm thickness using 2mL accelerant.

... During last years, terrorist attacks as the Boston Marathon bombing in 2013 used blackpowder [3], while the train bombings in Madrid 2004 involved the use of dynamites [4]. Due to the increase on the use of these devices for attacks in public and populous locations (airports, public transports, restaurants, shopping centres, theatres, etc.), the detection of explosives present an intensely priority for public security and as a result, there is a great demand of analytical techniques specially designed for this objective [2,[5][6][7]. ...

... Unfortunately, the continuous threat of worldwide terrorist activities are becoming necessary to design new analytical methodologies for fast and robust explosive detection and identification methods, strongly demanding specific requirements for those novel methodologies. Requirements such as minimizing the risk of analysts and operators during sample manipulation and analysis, reducing the possibility of sample contamination or destruction by developing non-contact and non-destructive, and when possible, portable technologies to place in the crime scene, are now the main target in forensic science [1][2][3][4]. ...

... The paper manufacturing processes are improved to fabricate homogeneous batches along time. Moreover, the analysis and examination of questioned documents require nondestructive or minimal destructive techniques [1] [2]. As a consequence, an exhaustive and minimal destructive analysis of paper is pursued in the ...

This work reports an investigation for the analysis of different paper samples using capillary electrophoresis with laser-induced detection. Papers from four different manufactures (white-copy paper) and four different paper sources (white and recycled-copy papers, adhesive yellow paper notes and restaurant serviettes) were pulverized by scratching with a surgical scalpel prior to their derivatization with a fluorescent labeling agent, 8-aminopyrene-1,3,6-trisulfonic acid. Methodological conditions were evaluated, specifically the derivatization conditions with the aim to achieve the best signal-to-noise signals and the separation conditions in order to obtain optimum values of sensitivity and reproducibility. The best conditions, in terms of fastest, and easiest sample preparation procedure, minimal sample consumption, as well as the use of the simplest and fastest CE-procedure for obtaining the best analytical parameters, were applied to the analysis of the different paper samples. The registered electropherograms were pre-treated (normalized and aligned) and subjected to multivariate analysis (principal component analysis). A successful discrimination among paper samples without entanglements was achieved. To the best of our knowledge, this work presents the first approach to achieve a successful differentiation among visually similar white-copy paper samples produced by different manufactures and paper from different paper sources through their direct analysis by CE-LIF and subsequent comparative study of the complete cellulose electropherogram by chemometric tools.This article is protected by copyright. All rights reserved

Tris(2,2'-bipyridine)ruthenium(II) chemiluminescence was investigated for the detection of 3,4-methylenedioxymethamphetamine (MDMA) and several related compounds in street drug samples. Optimization using flow injection analysis showed that the selectivity of the reagent can be targeted towards the detection of secondary amines by altering the pH of the reaction environment. The greater selectivity of this mode of detection, compared to UV-absorbance, reduces the probability of false positive results from interfering compounds. The detection limit for MDMA under these conditions was 0.48 μM. A HPLC method incorporating post-column tris(2,2'-bipyridine)ruthenium(II) chemiluminescence detection was applied to the determination of MDMA in five street drug samples. The results obtained were in good agreement with quantification performed using traditional UV-absorbance detection, which demonstrates the viability of this method for confirmatory analysis of drug samples. This is the first report of tris(2,2'-bipyridine)ruthenium(II) chemiluminescence for the detection of MDMA and related amphetamine derivatives. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Thin-film-deposition techniques used to develop latent fingerprints are continuously maturing. Vacuum metal deposition (VMD) is a commonly used technique in which thin films of gold and zinc are sequentially deposited on a latent fingerprint in a low-pressure chamber. An emerging technique entails the conformal deposition of a columnar thin film (CTF) on a latent fingerprint in a low-pressure chamber. Although specialized apparatus exist for both techniques, we have determined that the VMD technique can be easily implemented in the CTF apparatus. Use of the same apparatus for both of those fingerprint-development techniques can reduce capital costs, process-development time, and provide impetus for field-ready apparatuses.

  • Hervé Ménard
  • Oyewumi Akinpelu
  • Nana A. Fiakpui
  • Niamh Nic Daéid

The use of forensic evidence has become indispensable in many countries and jurisdictions around the world; however, the dissemination of research advancements does not necessarily directly or easily reach the forensic science community. Reports from the INTERPOL International Forensic Science Managers Symposium outline major areas that are of interest to forensic practitioners across the INTERPOL member countries. The information contained in the INTERPOL reports is extensive but can be challenging to process. The purpose of this research is to provide a comprehensive overview of the evolution of trends within the INTERPOL reports over an 18 year period. References relating to 10 evidence types retrieved from the 14th to 19th INTERPOL IFSMS reports (2004–2019) were processed and compared with data exports from the citation database Scopus covering the same evidence types. The results from this work are summarized by investigating the relationships between the 10 evidence types. To explore the outputs a user‐friendly R‐Shiny application was developed and is freely available at: https://uod.ac.uk/lrcfsinterpolreportsexplorer. This article is categorized under: Forensic Chemistry and Trace Evidence > Trace Evidence World map and collaboration network of documents cited in the 14th to 19th INTERPOL IFSMS reports (2004–2019).

  • Sean Goggins
  • Christopher G. Frost Christopher G. Frost

Diagnostic assays that rely on molecular interactions have come a long way; from initial reversible detection systems towards irreversible reaction indicator-based methods. More recently, the emergence of innovative molecular amplification methodologies has revolutionised sensing, allowing diagnostic assays to achieve ultra-low limits of detection. There have been a significant number of molecular amplification approaches developed over recent years to accommodate the wide variety of analytes that require sensitive detection. To celebrate this achievement, this comprehensive critical review has been compiled to give a broad overview of the many different approaches used to attain amplification in sensing with an aim to inspire the next generation of diagnostic assays looking to achieve the ultimate detection limit. This review has been created with the focus on how each conceptually unique molecular amplification methodology achieves amplification, not just its sensitivity, while highlighting any key processes. Excluded are any references that were not found to contain an obvious molecular amplifier or amplification component, or that did not use an appropriate signal readout that could be incorporated into a sensing application. Additionally, methodologies where amplification is achieved through advances in instrumentation are also excluded. Depending upon the type of approach employed, amplification strategies are divided into four categories: target, label, signal or receptor amplification. More recent, more complex protocols combine a number of approaches and are therefore categorised by which amplification component described within was considered as the biggest advancement. The advantages and disadvantages of each methodology are discussed along with any limits of detection, if stated in the original article. Any subsequent use of the methodology within sensing or any other application is also mentioned to draw attention to its practicality. The importance of amplification within sensing is wholly emphasised while perspectives on the future direction of the field are also shared.

Before amalgamating published isotope data, comparability should be demonstrated. This paper compares carbon and oxygen isotopic compositions of 30 enamel samples measured by two laboratories. The aims were to see what, if any, isotopic variation was observed, to determine the causes as needed and to correct if possible. Bioapatite was acidified at 90°C in 2006 and at 26°C in 2017, while δ values were corrected via one‐point normalization in 2006 and by two‐point normalization in 2017. One case (of the 30) produced different δ values between the analysis dates, suggesting contamination. Repeated carbon isotope ratio measurements were not meaningfully different. Repeated oxygen isotope ratio measurements were significantly different, even following correction for acid‐carbonate fractionation at different temperatures and the renormalization of 2017 δ values using one point; however, differences were not meaningful for interpretations. Results were used to calculate real interpretative differences (RIDs) for comparing enamel bioapatite as 0.6‰ for δ¹³C values and as 1.6‰ for δ¹⁸O values.

  • Xiaogang Lu
  • Zixuan Zhang
  • Haibo Liu
  • Junhua Xiao

Chemical forensics has been widely recognized as an important tool to investigate alleged use of chemical weapons and/or to identify the illicit production of chemical warfare agents. This paper describes the use of gas chromatography and mass spectrometry (GC-MS) to determine chemical attribution signatures (CAS) N,N-dimethylphosphoramidic dichloride (DMPADC), a key precursor of tabun, for tracking the production of tabun. Synthetic samples were identified and classified by using GC-MS and chemometrics. Analysis samples (n = 27) were collected from three synthetic DMPADC routes; 20 potential CAS were identified, and the structures of five CAS were assigned. Principal component analysis (PCA) was performed to summarize the distribution trend of the samples and to check for the presence of outliers. A Partial least squares discriminant analysis (PLSDA) model was established to discriminate and classify the synthetic samples. The proposed model in this paper has high predictive ability, and the test set samples can be correctly categorized.

  • Barbara B Wheeler

This chapter provides the student with a practical overview of microscopic examination employed within the field of forensic science. The microscope can be used to perform presumptive tests for forensic drug analysis. These tests provide the analyst with an initial idea of what drug might be present so that other tests can be performed to conclusively identify the substance. Color tests and microcrystalline tests are commonly conducted as preliminary drug tests. This gives the analyst helpful information so that subsequent and appropriate confirmatory testing can be performed. The chapter presents step‐by‐step procedures to help the student develop a basic understanding of the difference between presumptive and confirmatory tests and color and microcrystalline tests used for drug testing. It lists the equipment and supplies required, along with standard laboratory safety procedures for this experiment. The chapter concludes with report requirements, report questions and numerous references for further reading.

  • Barbara B Wheeler

This chapter provides the student with a practical overview of the characteristics of elongation and birefringence relevant to the field of forensic science. The optical properties of materials are used to characterize and distinguish different samples. When using the polarized light microscope to determine sign of elongation and birefringence, it becomes another valuable tool in a forensic laboratory. The chapter presents step‐by‐step procedures to help the student develop a basic understanding of common compensators, sign of elongation of fibers, birefringence of fibers, use of the polarizing light microscope to determine sign of elongation, and use of compensators to determine birefringence of fibers. It lists the equipment and supplies required, along with standard laboratory safety procedures for this experiment. The chapter concludes with questions, report requirements and numerous references for further reading.

  • Barbara B Wheeler

This chapter provides a practical overview of fluorescence microscope employed within the field of forensic science. It presents step‐by‐step procedures to help the student develop a basic understanding of: components of the fluorescence microscope, fluorescence, and use of the fluorescence microscope to observe sample fluorescence. As with the polarized light microscope, components can be added to a microscope so that particular sample characteristics can be examined. The fluorescence microscope allows the forensic scientist to observe sample fluorescence. When using the fluorescence light microscope to determine a sample's fluorescent characteristics, it becomes another valuable tool in a forensic laboratory. The chapter concludes with equipment and supplies, report questions, and report requirements.

Nano-structured materials find promising benefits for surface-based nanoscience and technology. To come across the drawbacks viz. low sensitivity, high background encumbrance, complicated setup, and poor universality in traditional techniques for improvement of latent fingerprints (LFPs) and biosensing applications, we develop the Zn1−xCuxO (x=0, 0.025, 0.05 and 0.075) nanoparticles through co-precipitation route. LFPs stained by the optimized Zn1−xCuxO (x=0.05) nanoparticles reveals well distinct ridge patterns with high sensitivity, low background hindrance on various porous and non-porous surfaces. Cyclic voltammetry (CV) results showed that the Cu incorporation ZnO lattice significantly improved the electrochemical activity towards uric acid. The materials were characterized by XRD, FTIR, FESEM, TEM, UV–Vis, Raman spectroscopy, and PL. Bandgap energy was determined by Tauc's plots which rised from 3.37 to 3.41 eV with Cu increasing to 5 mol% and then decreases from 3.41 to 3.31 eV, with Cu increased from 5 to 7.5 mol%. The rise of the Cu doping content in the ZnO host lattice has been shown enhanced photoluminescence (PL) properties with noticeable violet (423 nm) and blue emission (478 nm) in the visible region. Our study reveals a new prospect of using optimized Cu doped ZnO nanoparticles for research in biosensing and forensic applications.

p class="JCEbodytext"> COVID-19 severely disrupted the way students, worldwide, are taught. Courses that rely on hands-on activities to achieve their educational goals have been particularly affected because not all practical skills can be taught effectively outside specialized spaces like laboratories. In spite of the unplanned shift to distance learning, instructors at UNAM's Forensic Science Undergraduate Program seized this opportunity to engage in a careful examination of teaching practices in the Organic Chemistry laboratory and the role these practices play in realizing the goals of the curriculum. To assess laboratory teaching, we analyzed the laboratory activities completed before shutdown against the criteria of three assessment instruments. Overall, the tasks carried out in the laboratory appear to favor the development of conceptual understanding and the acquisition of technical proficiency in the use of materials and instruments. However, it seems that these aims overshadow other important ones and leave little time for reflection on aspects of the nature of science that could strengthen the research background of forensic scientists. Determining how to adapt laboratory teaching to distance learning must be preceded by a thorough appraisal, not only of the technical obstacles, but also of the aims of the curriculum—particularly when teaching chemistry to non-chemists. </p

  • Piyush K Rao Piyush K Rao
  • Maithri Tharmavaram
  • Gaurav Pandey

Forensic science utilizes expertise of various branch of science for the purpose of law and justice system. Forensic biology deals with analysis and detection of the samples from biological origin. In forensic chemistry, analysis of chemical compounds that are present at the crime scene is done, and it also involves identification of the unknown compound at the crime scene. Forensic physics is the utilization of concepts of physics for analysis and detection and comparison of sample obtained from scene. Questioned documents and fingerprint analysis are done for identification and comparison of individual characteristics that are present in evidence. Cyber forensics is used for retrieval of data from different exhibit and identification of the location and source of cyber‐attack. Crime scene management deals with protection of the crime scene, collection of evidence, maintaining chain of custody, and crime scene reconstruction. This chapter discusses about the conventional techniques that are utilized in the aforementioned branches of forensic science. Chromatography is used for isolation and detection of components. Spectrometry is used for identification of compounds through spectra, and microscopy is used for comparison of the sample and also for the visualization of the different samples using different illumination technique. Whereas digital forensic tools are used for data retrieval and identification of source of cyber‐attack. Psychological evaluation instruments such as polygraph and narco‐analysis are used for recalling and gathering of information from the suspect, and crime scene management tools are used for collection, packaging, and transportation of evidence from the crime scene.

  • Subbiah Thangadurai Subbiah Thangadurai

The emergent threat of terrorism activities has caused an urgent need of improved forensic explosive analysis. Complex matrices, limited samples, and confusing interpretations serve as challenges for a forensic chemist in order to link the evidence to the perpetrator of the crime. Forensic investigators use the analysis of explosive residues to spot materials and people concerned in an exceedingly crime. Over the past several decades, Ion mobility spectrometry (IMS) has evolved into an inexpensive and powerful analytical technique for the detection of gas phase samples at ambient pressures and temperatures. Each and every one of IMS instruments operate with an electric field that provides the space separation, but a number of IMS instruments also operate with a drift gas flow which provides also a temporal separation. Each type of IMS has four main regions: sample introduction system; ionization area; drift tube (where separation or selection occurs) and detection area. The availability of analyzers for general use from instrument vendors has initiated a new stage of development with IMS. IMS may be a sensitive analytical technique that's used for detection, identification and watching of chemicals, chiefly explosives, extremely nephrotoxic gases and drug interdiction. It offers a wide range of applications configurations and possibilities for use in field and process analytical applications. Post-detonation debris contains residues of unexploded materials which have to be sorted out from innocent debris. The excellent mass detection limits, rapid analysis time, superior resolution, and extremely small sample requirements of IMS method is attractive for the forensic analysis of the explosive materials. When fast detection of chemical warfare agents in the field is required, the IMS may be the only suitable option. This article provides a vital survey of the different IMS detection technologies. This critique review will provide the reader with a perceptive view of the main uniqueness and aspects of the IMS technique. Keywords: APCI; Explosives; Forensic Science; Post-Detonation; IMS; Terrorist

  • Renato Teodoro Ferreira de Paranaíba
  • Carlos Benigno Vieira de Carvalho
  • Jorge Marcelo de Freitas
  • Sérgio Martin Aguiar

Recently, Brazilian Federal Police used forensic chemistry and forensic botany techniques on a case. Two packets containing fragmented plant matter were seized and sent for forensic analysis. Forensic chemistry, the gold standard for evaluating plant material suspected to contain illicit substances, did not find illicit materials. Gas chromatography coupled mass spectrometry (GC-MS) identified thujone in the botanical material. Thujone is a chemical compound naturally found in many plant species, notably Artemisia absinthium. Because doubt remained, we next used plant DNA barcoding methods. Total DNA from plant tissue fragments was extracted and five different DNA regions were amplified, sequenced, and analyzed using plant DNA barcoding methods. Genetic analysis yielded 30 good quality sequences representing five taxa. Most specimens were identified as A. absinthium. Few studies focus on practical forensic applications of plant DNA barcoding methods using a case solved in a forensic laboratory with its difficulties and limitations. To the best of our knowledge, this is the first study to report an effective joint effort of forensic chemistry and botany techniques to assess plant material in Brazil. The availability of a new technical approach for the genetic sequencing of plant species will enhance many forensic investigations and inspire similar initiatives.

Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  • Phillip M. Mach
  • Guido F. Verbeck

Environmental forensics utilizes analytical scientific approaches to address the release and sources of contamination within the environment. These methods often seek to reconstruct the history of deleterious environmental events, their sources, and amounts of chemicals released into the environment. Forensic methods couple well-regarded scientific approaches within the legal framework. This due diligence provides tangible science-based results that are important in a regulatory context, including chemical identification, transport of contaminants, and determinable operational histories. Problems environmental forensics address include identifying sources of contamination, defining time frames of emission, and coupling observed conditions to potential sources of contamination.

1,3-dimethylamylamine (DMAA) is an alkylamine with stimulating properties that has been used predominantly as an additive in dietary supplements. DMAA is mostly consumed by professional athletes, and several doping cases reported since 2008 led to its prohibition by the World Anti-Doping Agency (WADA) in 2010. Adverse effects have indicated DMAA toxicity, and there is few data regarding its safety, so it was banned by regulatory agencies from Brazil and the United States. Ambient ionization methods such as Direct Analysis in Real Time Tandem Mass Spectrometry (DART-MS/MS) are an alternative for dietary supplements analysis, because they enable the analysis of samples at atmospheric pressure in a very short time and with only minimal sample preparation. Therefore, the aim of this work was to develop a methodology by DART-MS/MS to detect the presence of DMAA, ephedrine, synephrine, caffeine, sibutramine, and methylphenidate in 108 dietary supplements seized by the Brazilian Federal Police (BFP). The results show that DART-MS/MS screening was successfully employed to simultaneously detect the six substances in casework samples with rapid and reliable results and with minimum sample preparation. DMAA was present in 20% of the seized dietary supplements, being more prevalent along with sibutramine and caffeine. Out of the 108 samples, almost 50% were positive for sibutramine and 10% for methylphenidate. It appears that even after prohibition, dietary supplements and weight-loss products containing DMAA are still being commercialized.

  • Yuqin Li
  • Chaoying Xu
  • Chang Shu
  • Peng Wu

Fingerprints are unique and life-long to everyone, so they occupy very important statuses in forensic science. However, due to the limit of current imaging technologies and instruments, recognition and matching of fingerprints are mostly based on their level 2 structures (bifurcation, crossover, and etc.). Moreover, in real-world cases, fingerprints collected in the field are often incomplete or damaged, which adds further difficulty in fingerprint analysis. Quantum dots (QDs) are superior fluorescent imaging agents for latent fingerprints, which can provide both level 2 and level 3 (sweat pores) details. Here, we used red-emitting N-acetylcysteine-capped CdTe QDs as imaging agent for staining of eccrine LFPs. The numbers of level 2 and level 3 features that can be mapped are significantly larger than those obtained by cyanoacrylate fuming, a standard technique being adopted at forensic scene. Therefore, the level 2 and level 3 characteristics from QD-staining were simultaneously extracted for improved fingerprint analysis. A preliminary fingerprint matching based modified Pore Matching algorithm was thus developed based on the integration of both level 2 and level 3 characteristics. Satisfactory results of fingerprint matching were obtained, demonstrating the advantage of the QD-staining for advanced fingerprint analysis.

In the United States, sudden unexpected deaths attributable to diseases of the cardiovascular system account for almost 50% of all natural deaths with up to 600,000 deaths per year. Over the past decade, substantial developments have been made to provide definitive determinations in the diagnosis of cardiac death for adjudication in the criminal justice system and closure for decedent's families. In order to make postmortem diagnostic determinations, coordinated multidisciplinary efforts include collaboration between clinical and forensic pathologists. Forensic protocols include examination of the heart, histological sampling, toxicology testing, and molecular analyses. Lack of alternative diagnoses generally prompts pathologists to report sudden cardiac arrest as the main cause of death in many cases even though the accuracy of this finding might be in question; therefore, a forensic pathologist should examine unexplained cases of death in more depth to avoid this possible misdiagnosis.

Forensic sciences deal with the application of scientific knowledge to legal problems and are vital tools for unearthing the truth in any legal proceeding. In some subareas of forensic science, for example, in forensic botany, simple observation of plant samples collected at the crime scene could be enough for arriving at important conclusions, while in other forensic methods, such as forensic chemistry, sophisticated instrumental analytical methods are required. The most frequently encountered examples of forensic science applications are fingerprints and DNA analyses, both aiming at the identification of crime victims or criminals. Hyperspectral imaging (HSI) offers significant potential for the detection, visualization, identification, and age estimation of forensic traces, also allowing forensic analysis of document forgery. Various engineering disciplines, including mechanical, electrical, and chemical engineering, and fire science, are also involved in forensic investigations, often in civil cases, but also in criminal investigations.

Medical devices benefit from the recent growth of wireless technology for measuring physiological signals for both implantable and wearable systems. Implantable biomedical devices are made wireless in order to increase patient comfort as well as to make the implanted device robust. There is considerable demand for the development of miniaturized, low power, and energy efficient wireless telemetry systems for biomedical sensing and recording devices.

  • Adrien Bessaguet

La nature représente une source d'inspiration inépuisable pour les scientifiques. Depuis de nombreuses années, les chimistes se sont attaqués à la synthèse totale de produits naturels de plus en plus complexes. Ces efforts ont conduit non seulement à la préparation d'analogues artificiels possédant des propriétés inédites, mais également à la découverte de nouvelles réactions.Bien que de nombreuses générations de chimistes aient été inspirées par la structure des produits naturels, l'imitation des processus utilisés par la nature pour la synthèse des composés organiques a reçu beaucoup moins d'attention. Afin de préparer les molécules essentielles à leur survie, les systèmes vivants utilisent des réseaux moléculaires hautement sophistiqués, constitués de composants interconnectés comme l'ADN, l'ARN, les protéines et les petites molécules. Ces réseaux moléculaires fabriquent des produits naturels extrêmement complexes en contrôlant la formation et la rupture de liaisons chimiques de manière très efficace. Au cours de ces processus, les systèmes vivants utilisent souvent des machines moléculaires fonctionnant de manière processive. Par exemple, des machines moléculaires naturelles telles que la polycétide synthase, l'ADN polymérase ou le ribosome sont intégrées dans des réseaux biochimiques conçus pour la construction itérative de macromolécules naturelles tels que les biopolymères. De plus, ces processus de synthèse sont principalement régulés par des stimuli externes (ATP, pH, enzymes…) qui permettent de contrôler rigoureusement le processus de synthèse.La conception de réseaux moléculaires artificiels, pouvant rivaliser avec les processus naturels de synthèse, pourrait apporter un nouveau paradigme en chimie organique. Ainsi, l'objectif de ces travaux de recherche est de développer des réseaux moléculaires bio-inspirés et programmés pour la synthèse itérative de molécules organiques. Dans ce projet de recherche fondamentale, nous proposons d'étudier un réseau moléculaire polyvalent dédié à la préparation d'une large gamme de composés organiques. Ce dernier sera constitué (1) d'un amplificateur catalytique à base de caténane et (2) d'une machine moléculaire artificielle à base de rotaxane imitant la processivité des polymérases naturelles.

In forensic analysis, a small quantity of a particular material (hairs, fibers, soils, glasses, paints, among others) can be important to elucidate the sequence of events in a crime scene or to establish the relationship among subjects and facts. There are several examples of cosmetics used as forensic evidences, such as lipsticks and nail polishes. The composition of nail polishes varies according to brand, color and purpose of the product. In this work, the separation of Brazilian nail polishes according to their brand was evaluated using a portable energy dispersive X-ray fluorescence spectrometer (EDXRF) and principal component analysis (PCA). The nonsupervised classification of five brands indicates that the proposed methodology may be a quick, low cost and green alternative to discriminate brands and other characteristics related to a nail polish sample, as possible evidence in crime scenes.

  • Piotr Konieczka Piotr Konieczka

One of the main developmental trends in chemical analytics is the determination of analytes at ever decreasing detection levels in samples with increasingly complex matrices. This is an extremely difficult and complicated task therefore it poses a great challenge to analytical chemists, and it requires that appropriate attention be paid to the Quality Assurance and Quality Control (QA/QC) of the obtained measurements. In this article QA/QC system is described. Following topics are discussed: (1) measurement uncertainty, (2) traceability of analytical results, (3) reference materials, (4) interlaboratory comparisons and (5) method validation. The problems and challenges during method validation process are presented.

The product resulting from the reaction between 1,2-indanedione and ethylene glycol under acidic catalysis is 2,5,7,10-tetraoxapropellane and not 1,2-dispirane as previously reported. Similar reactions also occur with 2-mercaptoethanol and 1,2-ethanedithiol, which form analogous propellanes and not corresponding thioacetals. This explains the difficulty of removing the protective groups under acidic conditions. These findings were corroborated by quantum chemical calculations. Under similar conditions, the longer-chain diol, 1,3-propyleneglycol and its thiol-analogue, 1,3-propanedithiol, form only mono-acetals, even when a 3-fold excess of the diol is applied. The nucleophilic attack, however, takes place at different positions: while propanedithiol forms the acetal at c-1, propylene glycol forms the acetal at c-2.

Ninhydrin is an essential tool in the analysis of amino acids, peptides, and proteins, and the preferred reagent for the detection of latent fingerprints on porous surfaces. The goal of this investigation was to prepare ninhydrin analogs with enhanced chromogenic and fluorogenic properties. Target compounds included structures with extended conjugation and (or) with the presence of sulfur-containing moieties. We have devised general convergent routes for novel heterocyclic and aryl-substituted ninhydrin analogs for use as reagents for amino acid detection.Key words: ninhydrin analogs, synthesis, ketals, Suzuki cross-coupling reactions, Stille cross-coupling reactions.

A study focusing on the ability to utilize isotopic analysis of Pb used in small arms projectiles from varying geographic origin was undertaken using the GV Instruments Isoprobe multicollector inductively coupled plasma mass spectrometer. With the exception of two classes of ammunition, these samples were able to be distinguished from one another. Also, following rigorous normalization and mass bias correction, these data were compared to data collected by geochemists in localities corresponding to projectile manufacture. This comparison was successful when projectiles in certain economically isolated countries were analyzed. Pb isotopic analysis with MC−ICPMS is shown to be useful as a tool for distinguishing between ammunition of various manufacturing origins.

  • M. L. Patchett
  • Y. Minoshima
  • Peter B Harrington Peter B Harrington

Several γ-hydroxybutyrate (GHB) samples were analyzed using a commercial ion mobility spectrometry (IMS) instrument operated in negative mode, which is designed for explosive detection. The positive mode was primarily used for drug detection and the negative mode was used for explosive detection. In positive-ion mode, the instrument uses a nicotinamide reagent ion, which is also used as an internal calibrant for calculating reduced mobilities. In negative-ion mode, the instrument used chloride reagent ions furnished by hexachloroethane and methyl salicylate serves as an internal standard for calculating reduced mobilities.

A reference standard for γ-hydroxybutyric acid (GHB) free acid is not commercially available, making its analysis in forensic exhibits more difficult. GHB free acid is typically encountered in aqueous solution and in the presence of the lactone, γ-butyrolactone (GBL), presenting difficulty in Fourier transform infrared (FT-IR) analysis. The strong infrared (IR) absorptivity of the GBL carbonyl band, the shifting of the GBL carbonyl band in aqueous solutions, and the position of the O–H bend for water can mask the main carbonyl band for GHB free acid. Model solutions of β-hydroxybutyric acid (BHB) and GBL were studied in order to further understand the masking of the GHB free acid carbonyl band in FT-IR analysis. The use of second derivative FT-IR spectroscopy was shown to provide resolution of the free acid carbonyl band, and a presumptive test for GHB free acid was developed and applied. An extension of this work included preparing, for use as a standard reference material, small amounts (≤10 mg) of GHB free acid. Preparation was based on the instantaneous reaction of GHB's sodium salt with a stoichiometric amount of hydrochloric acid in aqueous solution, and subsequent isolation of the free acid in neat liquid form. Both FT-IR and proton nuclear magnetic resonance spectra of the neat reference material were obtained and used to verify its identity. The isolation of GHB free acid from actual forensic exhibits is also presented, with identity confirmation using FT-IR.

Recent advances in analytical techniques have enabled the detection of drugs and drug metabolites in oral fluid specimens. Although GC-MS is still commonly used in practice, many laboratories have developed and successfully validated methods for LC-MS(-MS) that can detect a large number of compounds in the limited sample volume available. In addition, several enzyme immunoassays have been commercialized for the detection of drugs of abuse in oral fluid samples, enabling the fast screening and selection of presumably positive samples. A number of concerns are discussed, such as the variability in the volume of sample collected and its implications in terms of quantitative measurements, and the drug recoveries of the many different specimen collection systems on the market. Additional considerations that also receive attention are the importance of providing complete validation data with respect to analyte stability, matrix effect, and the choice of collection method.

  • Alan Izenman Alan Izenman

Prosecuting those arrested for the unlawful possession, distribution or importation of illicit drugs, such as powder cocaine, crack cocaine, heroin and LSD, is usually both time­consuming and expensive, primarily because of the need to determine "beyond a reasonable doubt" the total amount of drugs seized in each case. Accuracy is important since penalties (imprisonment or fines) depend upon the quantity seized. Substantial backlogs in processing drug cases often develop as a result. In some jurisdictions, complete testing and analysis of all substances seized froma defendant are customary in support of a case, while in other jurisdictions randomsampling of drugs and the subsequent presentation of an estimate of the total amount seized have been used for many years. Due to pressure from crime laboratories and prosecutors, who point to major increases in their caseloads as well as a trend toward decreasing funding and staffing for the crime laboratories, jurisdictions which currently carry out a complete census of all seized evidence are now seriously considering a change in their methodology with a view to instituting new guidelines for the scientific sampling of evidence. In this article, we discuss the statistical and legal issues that have arisen in cases involving illicit drugs.

A thorough review of the application of solid-phase microextraction (SPME) combined with gas chromatography for the analysis of forensic specimens is presented, including experimental results for several recent applications. The SPME applications covered in this comprehensive review include ignitable liquid residues (also referred to as accelerants), explosive traces, drugs and poisons from biological specimens, and other forensic applications. Recently developed SPME methods are also presented, including the analysis of ignitable liquid residues on human skin, odor signatures, and several drug applications such as free-fraction antipsychotic drug levels, blood alcohol casework, drink-tampering analysis, and gamma-hydroxybutyrate identification without the need for derivatization. SPME is shown to be an inexpensive, rapid, and sensitive method for the analysis of a variety of forensic specimens.

Background: Carbon isotope ratio methods are used in doping control to determine whether urinary steroids are endogenous or pharmaceutical. Methods: Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) was used to determine the δ13C values for 5β-androstane-3α,17β-diyl diacetate (5βA), 5α-androstane-3α,17β-diyl diacetate (5αA), and 5β-pregnane-3α,20α-diyl diacetate (5βP) in a control group of 73 healthy males and 6 athletes with testosterone/epitestosterone ratios (T/E) >6. Results: The within-assay precision SDs for 5βA, 5αA, and 5βP were ± 0.27‰, ± 0.38‰, and ± 0.28‰, respectively. The between-assay precision SDs ranged from ± 0.40‰ to ± 0.52‰. The system suitability and batch acceptance scheme is based on SDs. For the control group, the mean δ13C (SD) values were −25.69‰ (± 0.92‰), −26.35‰ (± 0.68‰), and −24.26‰ (± 0.70‰), for 5βA, 5αA, and 5βP, respectively. 5βP was greater than 5βA and 5αA (P <0.01), and 5βA was greater than 5αA (P <0.01). The means − 3 SD were −28.46‰, −28.39‰, and −26.37‰ for 5βA, 5αA, and 5βP, respectively. The maximum difference between 5βP and 5βA was 3.2‰, and the maximum 5βA/5βP was 1.13. Three athletes with chronically elevated T/Es had δ13C values consistent with testosterone administration and three did not. Conclusions: This GC-C-IRMS assay of urine diols has low within- and between-assay SDs; therefore, analysis of one urine sample suffices for doping control. The means, SDs, ±3 SDs, and ranges of δ13C values in a control group are established. In comparison, testosterone users have low 5βA and 5αA, large differences between 5βA or 5αA and 5βP, and high 5βA/5βP and 5αA/5βP ratios.

Ninhydrin developed fingerprints can be enhanced by treatment with a zinc or cadmium salt. The resulting fingerprint luminescence has been attributed to the induced coplanarity of the bicyclic indanedione rings of Ruhemann's purple due to complexation with the metal ions. This paper explores whether this effect also occurs in the 1,8-diaza-9-fluorenone (DFO)-amino acid adduct (1), formed from the reaction of DFO with amino acids. Molecular modeling studies of (1) indicate a relatively small out-of-plane angle of 24 degrees. 1H NMR studies indicate (1) is asymmetric about the C2 axis in contrast to what has been previously reported. Little, if any, enhancement of luminescence was observed with Zn, Cd, Ru or Eu treated DFO developed latent fingerprints. This lack of enhancement was also borne out by solution luminescence studies. Given this lack of enhancement of luminescence, solutions of (1) and the four metal ions above were analyzed by electrospray mass spectrometry (ESMS). This indicated the formation of predominantly 1:1 complexes of (1) with both Zn and Cd, and the 2:1 complex with ruthenium. No evidence of a Eu complex was found by ESMS.

  • María Colón
  • Gloria Rodríguez
  • Ramón Orlando Díaz

The value of a scientific analysis and the significance of the results are influenced by the degree to which the sample analyzed reflects the composition of the material or population under study. An appropriate methodology will result in representative sampling. Formulae for representative sampling protocols were evaluated, and an optimal formula to be used in a sampling plan for 'street' drug exhibits with a large number of units was selected. The selected formula was applied to choose a number of sample units for routine chemical analysis of controlled substances, with the analytical result considered to be representative of the entire lot of powdered drug units in the exhibit. The results obtained during the research demonstrate that adoption of the formula n = 20 + 10% (N = 20) [where n = sample size, N = total population (N ≥ 20)] can be used for selection of an appropriate representative sample from powdered street-drug exhibits. This sampling procedure results in forensic analyses of controlled substances which are supportable to a reasonable scientific certainty, and which are obtained in an efficient manner.

  • Richard S Frank
  • Sidney W Hinkley
  • Carolyn G Hoffman

Exhibits of illicit drugs in a large number of containers are frequently submitted to crime laboratories. The forensic chemist often needs to select randomly and then examine a number of these containers to provide information regarding the composition of the overall exhibit which is sufficient to support the requirements of the criminal justice system. Although various methods of sampling can be shown to provide samples that will allow statistical inferences to be made with a high degree of confidence, no procedure has been identified that specifically meets the sampling objectives associated with an exhibit of this sort. The authors have addressed this sampling problem by applying the probability theory of the hypergeometric distribution to the sampling of drug exhibits contained in multiple containers. The resulting model will permit strong probability statements to be made regarding the presence of the controlled substance in a predetermined quantity of the exhibit, thereby supporting the prosecution and sentencing of violators of controlled substance laws.

  • K. Srogi

The analysis of human hair is useful in monitoring the level of certain trace elements and drugs in humans. In this work specific problems of hair sampling and hair sample preparation have been presented. Also, application of hair analysis has been illustrated and discussed on the basis of examples from clinical and environmental chemistry. This paper covers an updated review of techniques utilized for hair analysis, including spectrometry and more sophisticated methodologies, with special emphasis put on gas chromatography-mass spectrometry and liquid chromatography.

  • Masataka Sakayanagi Masataka Sakayanagi
  • Jun Komuro
  • Yaeko Konda
  • Yoshihiro Harigaya

Destructive identification of ballpoint pen ink was performed using field desorption mass spectrometry (FDMS) to determine the basic dyes in ballpoint pen ink. Seven different brands of black, blue, and red ballpoint pen inks (total: 21 samples) were examined in this study. A 1-mm section was cut from an ink line drawn on paper and used as the sample. Extraction was performed with methanol. Analysis of each extract by FDMS showed the molecular ion peak of each dye and the black, blue, and red inks were then classified into 6, 6, and 6 types, respectively, based on the ions detected. The results indicated that it was possible to distinguish between manufacturers of ballpoint pens. This analysis of ballpoint pen inks was found to be effective and the method was applied to the analysis of an actual forensic sample.

The 1990s saw incredible progress in the synthesis, characterization, and the beginnings of applications for quantum dots. Dramatic improvements in particle dispersity and quantum efficiency of emission have brought the notion of authentic devices based on these materials closer to fruition. Nonetheless, there is still a need for better synthetic methods for making these materials on a large scale, with less toxic precursors.

The knowledge of the robustness/ruggedness of analytical processes is an essential feature in the analytical validation. The definitions and the different aims of such studies are given. A dual general procedure for checking robustness/ruggedness in both intrinsic and extrinsic validation is presented and the different steps are discussed. The denomination of "inertia study" is introduced to designate this methodology in extrinsic validation and precision and trueness tests are proposed inside the inertia study. Several experimental designs, depending on the goal of robustness/ruggedness study and the type of variables (quantitative or qualitative) are considered.

  • Christopher G. Worley Christopher G. Worley
  • S. Wiltshire
  • Thomasin C. Miller
  • Vahid Majidi

Numerous methods are available to forensic scientists for detecting fingerprints in which the prints are treated with various agents to enhance the visual contrast between the print and the surface. In the present work, the spatial elemental imaging capabilities of micro-X-ray fluorescence (MXRF) were used to visualize fingerprint patterns based on inorganic elements present in the prints. A major advantage of using MXRF is that the prints are left unaltered for other analyses such as DNA extraction or for archiving. Most of the fingerprints which were examined were imaged from the potassium and chlorine present in the print residue. Among the various prints studied, lower count rates were also observed in the elemental maps of Ca, Al, Na, Mg, Si, P, S, and the X-ray source scatter. A sebaceous oily fingerprint left by one subject was successfully imaged by MXRF, but sebaceous prints left by a different person were undetectable, indicating print elemental composition may be person and/or diet dependent. Prints containing substances that might be found in real world cases were also visualized including sweat, lotion, saliva, and sunscreen.

  • Catherine Murphy Catherine Murphy

Although there is a great deal of fundamental physics and chemistry to discover in nanomaterials, quantum dots can be used for fluorescence, photonics, and electrochemical applications

  • Mengxia Zhao B.Sc
  • Sichun Zhang
  • Chengdui Yang B.Sc
  • Xinrong Zhang Xinrong Zhang

A direct and sensitive method for the detection of methyl centralite (MC) and ethyl centralite (EC) as gunshot residues (GSRs) has been developed. This method uses desorption electrospray ionization (DESI)-tandem mass spectrometry and directly desorbs and detects analytes from surfaces without any sampling process. Typical transitions for MC and EC, m/z 241 to m/z 134 and m/z 269 to m/z 148, respectively, were used to improve the assay sensitivity. It has been shown that MC and EC can be detected on various surfaces, with detection limits of 5–70 pg/cm2. Interferences, detection time after shooting and the number of times hands were washed after shooting were also evaluated. None of the materials interfered with the results and the detection window for organic GSRs was up to 12 h and hands could be washed at least six times. Further samples were analyzed to confirm the reliability of this method, and showed that it could discriminate shooters from nonshooters. This method should be of significance in forensic science, especially in analyzing GSRs, because of its simplicity, high throughput, and the direct detection of MC and EC on suspects' hands, clothes, and hair.

  • Giampietro Frison
  • L Tedeschi
  • Sergio Maietti
  • Santo Davide Ferrara

A new method for the qualitative and quantitative analysis of γ-hydroxybutyric acid (GHB) in plasma and urine samples is described. It involves the conversion of GHB to γ-butyrolactone (GBL), its subsequent headspace solid-phase microextraction (SPME), and detection by gas chromatography/positive ion chemical ionization mass spectrometry (GC/PICI-MS), using D6-GBL as internal standard. The assay is linear over a plasma GHB range of 1–100 µg/mL (n = 5, r = 0.999) and a urine GHB range of 5–150 µg/mL (n = 5, r = 0.998). Relative intra- and inter-assay standard deviations, determined for plasma and urine samples at 5 and 50 µg/mL, are all below 5%. The method is simple, specific and reasonably fast. It may be applied for clinical and forensic toxicology as well as for purposes of therapeutic drug monitoring. Copyright © 2000 John Wiley & Sons, Ltd.

The reliability of analytical data is very important to forensic and clinical toxicologists for the correct interpretation of toxicological findings. This makes (bio)analytical method validation an integral part of quality management and accreditation in analytical toxicology. Therefore, consensus should be reached in this field on the kind and extent of validation experiments as well as on acceptance criteria for validation parameters. In this review, the most important papers published on this topic since 1991 have been reviewed. Terminology, theoretical and practical aspects as well as implications for forensic and clinical toxicology of the following validation parameters are discussed: selectivity (specificity), calibration model (linearity), accuracy, precision, limits, stability, recovery and ruggedness (robustness).

  • Cecilia Rustichelli Cecilia Rustichelli
  • V Ferioli
  • F. Vezzalini
  • G Gamberini

This paper reports the use of liquid chromatography for the separation and determination of the major cannabinoids extracted from hashish samples. The direct coupling to the mass spectrometer enables the selective identification both of neutral and acidic cannabinoids. The developed method does not require any preliminary derivatization and should, therefore, be of interest in forensic analysis for simple and unequivocal determination of hashish constituents.

In the past decade, capillary-electrophoresis (CE) techniques have been demonstrated to offer promising, effective and economic approaches for the separation of a large variety of substances, including those encountered in forensic analysis. Reliable, automated CE instruments have become commercially available and have advanced methods in forensic sciences. This article reviews applications of CE in the field of forensic analytical chemistry, covering the literature since the first publication appeared in the early 1990s and focusing on two applications: (i) explosive compounds and gunshot residues; and, (ii) inks and dyes.

  • Nicole Anastos
  • Neil W Barnett
  • Simon W Lewis Simon W Lewis

This paper reviews recent applications of capillary electrophoresis to forensic drug analysis and covers the literature since 2001. A brief overview of capillary electrophoresis is followed by a discussion of analytical applications which have been categorized into two sections: (i) drug seizures and non-biological samples, and (ii) forensic toxicology and biological samples.

  • H. G. M. Edwards H. G. M. Edwards
  • Joanna S. Day

The enhancement of latent fingerprints by controlled exposure to cyanoacrylate vapour in fuming cabinets is now an established technique for artefacts recovered from forensic crime-scene investigations. The basis of the method involves the deposition of the monomeric cyanoacrylate under warm, moist conditions onto the object following which the resulting polymerisation produces a white film which renders the fingerprint visible. In this Raman spectroscopic study we have investigated the presence of several bands in the spectra of polymerised ethyl-2-cyanoacrylate which indicate the presence of residual monomer and species formed by reaction of the polymerising material with the atmosphere. The possible effects of the presence of unreacted monomer and other impurities in the polycyanoacrylate films upon the spectral analytical identification of exogenous particles which are trapped on the latent fingerprint is highlighted. The possibility of reaction between functional groups in, for example, drugs of abuse and the reactive monomer sites which will hinder the unambiguous identification of these materials on the fingerprint surface is discussed in terms of the information obtained from the Raman spectra.

  • Masahisa Takatsu Masahisa Takatsu
  • Osamu Shimoda
  • Kyoko Onishi
  • Naoki Oguri

Optimization of a light emitting diode (LED)-based excitation system for the detection of pretreated fingerprint fluorescence is described. Fluorescent ridges can usually be excited by irradiation with forensic light sources such as xenon arc lamps or quartz-halogen lamps with high-power output and suitable filters. However, they are too expensive for many crime laboratories in smaller organizations. We concentrated on LEDs which have advantages over conventional light sources in that they are simpler and of lower cost, but the power output and quality of each individual LED unit is not sufficient for the detection of weak fluorescent ridges. To resolve this subject, blue and green LED arrays composed of ninety LED units were adopted and suitable low pass filters for them were designed. An experimental system, consisting of blue and green LED arrays with the suitable low pass filters for illumination, high pass filters for viewing, a digital camera and a computer, was tested. The fluorescent images of cyanoacrylate ester fumed/rhodamine 6G stained fingerprint on white polyethylene sheet and weak fluorescent ridges of ninhydrin/indium chloride treated fingerprint on white paper were successfully detected and photographed. It was shown that the improvement of LED beam in intensity and quality can compensate the disadvantages, resulting in well-contrasted images.

Current drug discovery involves a highly iterative process pertaining to three core disciplines: biology, chemistry, and drug disposition. For most pharmaceutical companies the path to a drug candidate comprises similar stages: target identification, biological screening, lead generation, lead optimization, and candidate selection. Over the past decade, the overall efficiency of drug discovery has been greatly improved by a single instrumental technique, liquid chromatography/mass spectrometry (LC/MS). Transformed by the commercial introduction of the atmospheric pressure ionization interface in the mid-1990s, LC/MS has expanded into almost every area of drug discovery. In many cases, drug discovery workflow has been changed owing to vastly improved efficiency. This review examines recent trends for these three core disciplines and presents seminal examples where LC/MS has altered the current approach to drug discovery.

16 pages, 6 figures, 2 tables.-- Printed version published Jun 2007.-- Issue title: Pharmaceutical-residue analysis. In the literature, many analytical methods have been described for the determination of illicit drugs in biological fluids. Urine is one of the preferred matrices for control of drugs of abuse because its analysis is considered non-invasive and the concentration of the compounds and their metabolites, as well as the volume of sample available, are higher than in other biological fluids. For the analysis of drugs of abuse in urine, liquid chromatography coupled to mass spectrometry (LC-MS) or tandem mass spectrometry (LCMS2) has become a powerful technique. Its main advantages are its selectivity and sensitivity, reduced need for sample preparation, absence of need for derivatization and reliability of results. In addition, when two selected reaction monitoring (SRM) transitions are recorded per compound, this technique provides the four identification points required by the European Union for identification and confirmation of illicit substances. For preconcentration or clean up of samples, specific procedures, such as those using mixed-mode solid phases, have allowed good recoveries and low limits of detection, and helped reduce ion suppression in LC-MS2. This review discusses methods published in 2000–2006 to determine the drugs of abuse consumed most (namely, amphetamines, methamphetamines, cannabinoids, cocaine, LSD and opiates) and their metabolites in urine, particularly by LC-MS2. This work has been supported by EU projects AQUATERRA [GOCE 505428] and MODELKEY (SSPI-CT-2003-511237-2) and by the Spanish Ministry of Education and Science through the project EVITA (CTM2004-06265-C03-01/TECNO). Tânia Mara Pizzolato gratefully acknowledges CAPES-Brazil for a post-doctoral grant. Peer reviewed

  • Meiqin Zhang
  • Hubert H Girault Hubert H Girault

An efficient strategy for visualizing human fingerprints on a poly(vinyldene difluoride) membrane (PVDF) by sanning electrochemical microscopy (SECM) has been developed. Compared to a classical ink fingerprint image, here the ink is replaced by an aqueous solution of bovine serum albumin (BSA). After placing the ''inked'' finger on a PVDF membrane, the latent image is stained by silver nitrate and the fingerprint is imaged electrochemically using potassium hexachloroiridate (III) (K3IrCl6) as a redox mediator. SECM images with an area of 5 mm · 3 mm have been recorded with a high-resolution using a 25-lm-diameter Pt disk-shaped microelectrode. Pores in the skin (40–120 lm in diameter) and relative locations of ridges were clearly observed. The factors relevant to the quality of fingerprint images are discussed.

  • Alan Izenman Alan Izenman

While many European justice systems distinguish between possession of and trafficking in illicit drugs, sentencing in drug cases in those countries tends not to depend (at least formally) upon the quantity of drugs seized from a defendant, but rather on the circumstances in which the defendant was found with drugs. Courts in the United States, on the other hand, penalize those convicted of drug crimes through an elaborate system of sentencing rules and guidelines. These sentences depend only upon the amount of drugs (possibly adjusted for circumstances) and the defendant's criminal history. Because of the enormous amount of work needed to determine drug type and quantity in each case, sampling the evidence and estimates of drug quantity have been accepted in most courts in the United States. During the last two years, several major developments in U.S. federal sentencing have taken place. It all started in June 2000 with the Supreme Court case Apprendi v. New Jersey, in which Justice O'Connor, in dissent, termed a "watershed in constitutional law". Prior to Apprendi, a judge would sentence a convicted drug trafficker to imprisonment using the preponderance standard of proof on the quantities of drugs seized. The affect of Apprendi is to make more juries decide the quantity of drugs by the reasonable doubt standard. Although Apprendi had nothing to do with illicit drugs, the implication now is that all federal sentencing protocols are under revision. Since Apprendi was decided, huge numbers of cases involving convicted drug traffickers have relied upon its reasoning on appeal, with the result that a ruling from the Supreme Court on further clarification of this issue is expected. This article discusses the impact so far of Apprendi on statistical issues involved in estimating total drug quantity and considers possible future directions under the changing protocols.

  • Demian R Ifa
  • Nicholas E Manicke
  • Allison L Dill
  • R. Graham Cooks

Latent fingerprints (LFPs) potentially contain more forensic information than the simple identification of the subject; they may contain evidence of contacts with explosives or substances of abuse. Chemical information can also be useful in resolving overlapping LFPs from different individuals. We used desorption electrospray ionization mass spectrometry in an imaging mode to record compound-specific chemical fingerprints.

  • Kenneth S. Webb
  • Peter B. Baker
  • Nicholas P. Cassells
  • Stephen A. White

A forensic procedure for the screening and confirmation of the presence of lysergide (lysergic acid diethylamide, LSD) in urine is described together with the evaluation of a novel enzyme immunoassay (EIA) and immunoaffinity extraction procedure. Following initial screening using either an established radioimmunoassay (RIA) or a novel EIA procedure, a quantitative estimate is established using a conventional high performance liquid chromatography-fluorescence (HPLC) technique following solid phase extraction. Final confirmation and quantitation, without derivatization, is established using HPLC in combination with electrospray ionization (ESI) mass spectrometry using methysergide as an internal standard. The detection limit of LSD in urine is 0.5 ng/mL. A blind trial confirmed the validity of the results. The choice of internal standard is discussed. Consideration is given to the photosensitivity of LSD solutions. A study of potential interferants in the HPLC-MS confirmation of LSD is presented and shows that for the wide range of compounds studied, there are none that would interfere with this confirmation technique. A comparison is shown between solid phase and immunoaffinity extraction/clean up procedures, and between RIA and EIA screening procedures.

  • C. Hartmann
  • Johanna Smeyers-Verbeke Johanna Smeyers-Verbeke
  • D.L. Massart
  • R.D. McDowall

A strategy is discussed for the validation of chromatographic methods that are developed to quantify drugs in biological matrices. Both the validation terminology and the hypothesis testing are briefly reviewed. The emphasis is on the design of the experiments required to allow a reliable conclusion about acceptance or rejection of the bioanalytical method. In particular, it is explained how to evaluate the calibration line, devise experiments to estimate precision and bias and how to determine the stability of the analyte between the time of the sample collection and the analysis of the processed sample.

  • Karsten Balon
  • Bernd Riebesehl Bernd Riebesehl
  • Bernd W Müller

Drug partitioning to liposomes has been suggested as a model for partitioning to biomembranes but has been lacking a rapid analytical assay useful for drug screening. A fast pH-metric titration method for the determination of liposome partitioning of ionizable drugs using small unilamellar phosphatidylcholine vesicles prepared by sonic homogenization has been successfully developed, enabling the use of high lipid-to-drug ratios. Liposome-water partition coefficients of diclofenac and propranolol were determined to study the impact of varying titration parameters, temperature, equilibration time, lipid, and liposome types on the partitioning. To validate this method, the results were compared to literature values generated with different techniques and to pH-metric titration results with large unilamellar vesicles. The rapid pH-metric assay gave liposome partitioning data for the two model compounds which were consistent with other analytical techniques and liposome types.

  • Colin Aitken

It is thought that, in a consignment of discrete units, a certain proportion of the units contain illegal material. A sample of the consignment is to be inspected. Various methods for the determination of the sample size are compared. The consignment will be considered as a random sample from some super-population of units, a certain proportion of which contain drugs. For large consignments, a probability distribution, known as the beta distribution, for the proportion of the consignment which contains illegal material is obtained. This distribution is based on prior beliefs about the proportion. Under certain specific conditions the beta distribution gives the same numerical results as an approach based on the binomial distribution. The binomial distribution provides a probability for the number of units in a sample which contain illegal material, conditional on knowing the proportion of the consignment which contains illegal material. This is in contrast to the beta distribution which provides probabilities for the proportion of a consignment which contains illegal material, conditional on knowing the number of units in the sample which contain illegal material. The interpretation when the beta distribution is used is much more intuitively satisfactory. It is also much more flexible in its ability to cater for prior beliefs which may vary given the different circumstances of different crimes. For small consignments, a distribution, known as the beta-binomial distribution, for the number of units in the consignment which are found to contain illegal material, is obtained, based on prior beliefs about the number of units in the consignment which are thought to contain illegal material. As with the beta and binomial distributions for large samples, it is shown that, in certain specific conditions, the beta-binomial and hypergeometric distributions give the same numerical results. However, the beta-binomial distribution, as with the beta distribution, has a more intuitively satisfactory interpretation and greater flexibility. The beta and the beta-binomial distributions provide methods for the determination of the minimum sample size to be taken from a consignment in order to satisfy a certain criterion. The criterion requires the specification of a proportion and a probability.

  • Della A. Wilkinson Della A. Wilkinson

This paper describes the study of the reaction between 1, 8-diazafluoren-9-one (DFO) with the amino acid L-alanine in methyl alcohol. Particular interest was paid to the possible role of the solvent which appears to react with the DFO to form a hemiketal that is the reactive species. A potential reaction pathway is proposed based on the current data collected. The reaction intermediates and products were identified by a variety of spectroscopic methods including mass spectrometry (MS), nuclear magnetic resonance (NMR) spectroscopy, and X-ray crystallography.

  • Steve M. Savoy
  • Sydney J. Ulvick
  • Mark R. Sudduth
  • E. R. Menzel

The concept of utilizing photoluminescent semiconductor nanocrystals for latent fingerprint detection, especially in concert with phase-resolved imaging for background fluorescence suppression, is reduced to practice with CdS nanocrystals that are capped with dioctyl sulfosuccinate. The nanocrystals are dissolved in heptane or hexane and are applied in much the same way as staining with fluorescent dye, on articles that have been pre-fumed with cyanoacrylate ester and also on the sticky side of electrical tape without pre-fuming. Since CdS can form a photoluminescent nanocomposite with dendrimers, a feasibility examination of dendrimer tagging of fingerprints has also been conducted.

CdS/dendrimer nanocomposites with a range of concentrations of the photoluminescent semiconductor nanocluster and the dendrimer are prepared in methanol and 1:9 methanol:water solutions. The solutions are utilized for detection of cyanoacrylate ester fumed and unfumed fingerprints on polyethylene and aluminum foil.

The ability of 1,2-indanedione and 5,6-dimethoxy-1,2-indanedione to detect latent prints on porous surfaces, as compared to DFO and ninhydrin, has been evaluated. Comparisons of prints developed under various conditions determined the optimum development conditions for the new reagents. The indanediones tested were found to have lower detection limits for glycine. The carrier solvent used was found to affect the quality of the prints developed. In Arklone, the new reagents developed prints that displayed superior luminescence to those developed with DFO. In HFE 7100, 1,2-indanedione and 5,6-dimethoxy-1,2-indanedione gave superior luminescence to DFO after zinc salt treatment and cooling with liquid nitrogen, both of which improve the luminescence of prints developed with 1,2-indanediones. 1,2-Indanediones could offer less expensive but effective alternatives to DFO. With further optimization, the new reagents may supersede DFO as the method of choice for the detection of latent fingerprints on porous surfaces.

  • Marc A LeBeau
  • Madeline A Montgomery
  • Mark L Miller
  • Steve Burmeister Steve Burmeister

The past few years have seen a dramatic increase in the abuse of gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) in the United States. The abuse stems primarily from their euphoric and sedative properties, but these substances are also misused by bodybuilders as steroid alternatives. Recently there has been an alarming increase in the use of GHB and GBL in crimes of drug-facilitated sexual assault. A rapid and sensitive procedure was developed for the analysis of biofluids containing GHB and GBL. Two separate aliquots of a biological specimen were spiked with an alpha-methylene-gamma-butyrolactone internal standard solution. One of the aliquots was treated with concentrated sulfuric acid for cyclization of GHB to GBL and the other remained untreated. Both aliquots were extracted with methylene chloride and concentrated. Extracts were screened using automated headspace gas chromatography-flame-ionization detection (GC-FID). Qualitative findings were quantitated and confirmed in a manner similar to the GC-FID procedure with some modifications. A calibrated solution of GHB-d6 (or GBL-d6, when warranted) was added to the aliquots at a concentration approximating the level determined by the GC-FID screen. The extraction was as described with conversion of GHB to GBL, but analysis was by full-scan gas chromatography-mass spectrometry (El). Quantitation was performed by comparison of the area of the molecular ion of the parent drug (m/z 86) to that of the calibrated deuterated analogue (m/z 92). This analytical procedure allows for the rapid detection of GHB and GBL in biofluids. Its sensitivity has proven useful for the toxicological investigation of cases of drug-facilitated sexual assault.

  • Maciej Bogusz Maciej Bogusz

The applications of LC-API-MS in routine forensic toxicological casework were presented. This technique has been used for routine determination of several groups of drugs: opiate agonists (like morphine, codeine, dihydrocodeine and their glucuronides, methadone, buprenorphine) cocaine and its metabolites (benzoylecgonine and ecgonine methyl ester), amphetamine and other psychoactive phenethylamines, like MDMA, MDE or MDA, benzodiazepine derivatives (flunitrazepam and metabolites, triazolam, bromazepam), hallucinogens (LSD, psilocybin, psilocin) and olanzapine, A common solid-phase extraction procedure for all drugs (with exception of LSD) has been developed. Among two ionization sources, atmospheric pressure chemical ionization appeared more universal and assured generally higher sensitivity. Only in the case of very polar drugs (e.g. psilocin or psilocybin) electrospray ionization was more sensitive. LC-API-MS became a very powerful and flexible method for dedicated analyses of substances of forensic interest. The use of this technique for general, broad applicable screening depends on the establishing of interlaboratory database of standardized mass spectra.

  • Ute Ramminger
  • Ulrich Nickel
  • Bernd Geide

A study of the reaction between ninhydrin and alanine has been carried out taking into account that, adhered on the surface of a dry porous medium such as paper, a quasi-heterogeneous reaction has to take place. Instead of amino acids released from human sweat glands, aqueous solutions of alanine were taken to deliver a given amount of amino acid to the sample. The dye density, obtained after using a standard development process, could noticeably be increased by setting a drop of water on the dye dot, thus indicating that not all the alanine had been used for dye formation during the usually applied process. The incomplete reaction can be explained by the problem of bringing the reactants into contact with each other when both are in the solid phase in the porous surrounding. The temporary presence of water allows a reorientation of the insoluble reactants. With fingerprints an increase in both the rate of development and the final dye density could be obtained when the sample was post treated after the developing process with the blank solvent, thus also the background coloration could be decreased. The ideas presented in this paper may form the basis for a modification of developing processes with ninhydrin in order to increase the proportion of amino acids present (in the sample) used in dye formation without data loss.

The present study describes a novel approach for utilizing liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) in qualitative screening analysis. An LC/TOFMS method was developed for screening toxicologically relevant substances in urine samples. After solid phase extraction and LC separation, the method included full spectrum acquisition followed by automatic internal calibration, searching against a target library, and reporting positive identifications. The target library, containing 433 toxicologically relevant substances in the mass range of 105-734 Da, was created simply by entering the elemental formulas of substances into the instrument software for the calculation of their respective monoisotopic masses. In addition to parent drugs, the library contained selected urinary drug metabolites, based on their structures available in the literature. Identification was based on the exact masses of the compounds. The LC/TOFMS method provided 5-10 ppm mass accuracy for a majority of identified compounds in authentic urine samples. Compared with established thin-layer and gas chromatographic methods, the LC/TOFMS method produced similar findings in urine with the additional advantage of metabolite identification without actual reference substances.

  • Kathryn S Kalasinsky
  • Marcie M. Dixon
  • Gregory Alan Schmunk Gregory Alan Schmunk
  • Stephen J. Kish

Despite the increasing incidence of illicit use of gamma-hydroxybutyrate (GHB), little information is available documenting levels of the drug in GHB fatalities. We measured GHB levels in postmortem blood, brain and hair specimens from a suspected overdose case by gas chromatography/mass spectrometry (GC/MS) following solid phase extraction (SPE) and derivatization with bis(trimethyl-silyl) trifluoroacetamide (BSTFA). Examination found 330 microg/mL GHB in femoral blood and 221 ng/mg GHB in frontal cortex brain tissue, values higher than those typically reported in the literature. The hair shaft was negative for GHB whereas the plucked root bulbs with outer root sheath attached (2,221 ng/mg) and root bulbs after washing and removal of the outer root sheath (47 ng/mg) contained the drug. Our results are consistent with an acute single dose of GHB and, as the toxicology screen was negative for other drugs of abuse, emphasize the significant danger of this drug.

  • Sheryl Blair Sheryl Blair
  • Meansup Song
  • Brad J. Hall
  • Jennifer S. Brodbelt

A simple method of detection was developed for gamma-hydroxybutyrate (GHB). The method involves the derivatization of GHB using a hexyl-chloroformate procedure in aqueous media (such as water or urine), extraction of the derivatization product directly from the sample using solid-phase microextraction, and subsequent separation and detection with gas chromatography quadrupole ion trap mass spectrometry. The deuterated form of GHB (GHB-D6) is used as an internal standard for quantitation. The method was linear for GHB-spiked pure water samples from 2 to 150 microg/mL GHB with a detection limit of 0.2 microg/mL. Spiked urine samples showed linearity from 5 to 500 microg/mL GHB with a detection limit of 2 microg/mL. The SPME-GC/MS method is applied to actual case samples, and the results are compared to those values obtained using a conventional GC/MS method. Sensitivity and linearity are comparable to those seen using traditional methods of separation, yet the SPME method is superior due to the simplicity, speed of analysis, reduction in solvent waste, and ability to differentiate between GHB and gamma-butyrolactone (GBL).

  • Francesco Saverio Romolo Francesco Saverio Romolo
  • Pierre Margot

A review of the scientific papers published on inorganic gunshot residue (GSR) analysis permits to study how the particle analysis has shown its capability in detection and identification of gunshot residue. The scanning electron microscope can be the most powerful tool for forensic scientists to determine the proximity to a discharging firearm and/or the contact with a surface exposed to GSR. Particle analysis can identify individual gunshot residue particles through both morphological and elemental characteristics. When particles are detected on the collected sample, the analytical results can be interpreted following rules of a formal general interpretative system, to determine whether they come from the explosion of a primer or from other possible sources. The particles on the sample are compared with an abstract idea of "unique" GSR particle produced by the sole source of the explosion of a primer. "Uniqueness" is not the only problem related to GSR detection and identification for a forensic scientist. With "not-unique" particles interpretation of results is extremely important. The evidential strength of "not-unique" particles can increase with a more fruitful interpretative framework based on Bayes rule. For the assessment of the value of a GSR in linking a suspect and a crime, it is important to compare two hypothesis: the first can be that of the evidence if the suspect has been shooting in a specific situation, the second that of the evidence if the suspect was not involved in this shooting. This case specific or case-by-case approach is closer to what the court is interested in. The authors consider that a "case-by-case" approach should be followed whenever possible. Research of models and data such as those developed in other trace evidence material (fibres, glass, etc.) using a Bayesian approach is suggested in the interpretation of GSR.

The multivariate curve resolution method SIMPLe to use Interactive Self-Modeling Mixture Analysis (SIMPLISMA) was applied to Fourier and wavelet compressed ion-mobility spectra. The spectra obtained from the SIMPLISMA model were transformed back to their original representation, that is, uncompressed format. SIMPULSMA was able to model the same pure variables for the partial wavelet transform, although for the Fourier and complete wavelet transforms, satisfactory pure variables and models were not obtained. Data were acquired from two samples and two different ion mobility spectrometry (IMS) sensors. The first sample was thermally desorbed sodium gamma-hydroxybutyrate (GHB), and the second sample was a liquid mixture of dicyclohexylamine (DCHA) and diethylmethylphosphonate (DEMP). The spectra were compressed to 6.3% of their original size. SIMPLISMA was applied to the compressed data in the Fourier and wavelet domains. An alternative method of normalizing SIMPLISMA spectra was devised that removes variation in scale between SIMPLISMA results obtained from uncompressed and compressed data. SIMPLISMA was able to accurately extract the spectral features and concentration profiles directly from daublet compressed IMS data at a compression ratio of 93.7% with root-mean-square errors of reconstruction < 3%. The daublet wavelet filters were selected, because they worked well when compared to coiflet and symmlet. The effects of the daublet filter width and compression ratio were evaluated with respect to reconstruction errors of the data sets and SIMPLISMA spectra. For these experiments, the daublet 14 filter performed well for the two data sets.