Forensics, Narcotics

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Collection of black fingerprints made with ink, isolated on a white background. Human fingerprint. | Image Credit: © domnitsky - stock.adobe.com

Scientists have developed a new method for predicting and assessing the source of black inks using direct analysis in real-time mass spectrometry. By applying dimensionality reduction techniques and likelihood ratio analysis, the researchers achieved high accuracy in identifying ink sources, demonstrating the potential of this approach in forensic ink analysis.

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The dried blood spot (DBS) sampling technique has been around for decades, predominantly for small molecules and mainly in newborn screening. Although determination of proteins after DBS sampling is usually performed with immunometric assays, the combination with mass spectrometry (MS) is gaining interest. This article provides an overview of DBS sampling for mass spectrometry-based protein analysis. The first part will focus on clinical applications for DBSs and on sampling other biological matrices apart from whole blood, including dried matrix spots (DMSs). The second part will explore the new frontiers of the DBS sampling technology, including novel sampling materials/devices, and novel combinations with mass spectrometry. Examples of use in both qualitative and quantitative protein analysis are highlighted as well as examples using both bottom-up and top-down proteomics approaches.

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LCGC Europe spoke to Leon Barron and Matteo Gallidabino to discuss novel nontargeted approaches to analyze explosive materials using ion chromatography (IC) with high resolution mass spectrometry (HRMS), and the challenges and solutions analysts can encounter when developing nontargeted methods.

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The detection of drugs or other toxic substances can be crucial to forensic investigations. However, if the investigation involves a heavily decomposed, skeletonized, or missing corpse, that information can be difficult to obtain, and may require the skills of a unique branch of forensic toxicology-entomotoxicology. To explain the role of chromatography in this field, The Column spoke to Paola A. Magni from Murdoch University, in Perth, Australia.

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A fully automated method for the effective drug screening of large populations based on dried blood spot (DBS) technology is presented. DBSs were prepared, scanned, then spiked with deuterated standards, and directly extracted, before they were transferred online to an analytical liquid chromatography (LC) column and then to the electrospray ionization tandem mass spectrometry (ESI-MS/MS) system. The method was applied to DBS samples from two patients with back pain; codeine and oxycodone could be identified and quantified accurately below the level of misuse of 89.6 ng/mL and 39.6 ng/mL, respectively.

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GC–MS is considered the gold standard in forensic trace evidence analysis because of its ability to chromatographically separate and analyze components in mixtures. Although GC×GC–MS has been used extensively in the oil and petroleum and flavour and fragrance industries, it has not been fully explored in the forensic sector. However, forensic scientists often encounter highly complex samples that would benefit from the capabilities of GC×GC–MS, such as, sexual lubricants, automobile paints, and tyres. GC×GC–MS analysis can allow for the deconvolution of coeluted components while providing increased sensitivity of minor components to help benefit any forensic laboratory.

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This article discusses the use of emerging technologies that are complementary to established techniques, to significantly reduce these shortcomings for both synthetic cannabinoids and synthetic cathinones. In this vein, the utility of recently reported approaches including ultrahigh performance supercritical fluid chromatography (UHPSFC)–photodiode array (PDA) ultraviolet (UV)–MS, and GC–vacuum UV is discussed. To increase the specificity of analysis, multiple chromatographic techniques are commonly used. For the analysis of emerging drugs, a combination of GC and UHPSFC is recommended. The utility of a previously unreported coupled-columns approach for UHPSFC to significantly enhance resolution of synthetic cathinones is presented.

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Analyzing drugs of abuse (DoA) in human bodily fluids is crucial for clinical research and forensic toxicology. In these routine analyses, a large number of samples must be investigated, with a potentially high laboratory cost for each sample. As such, a reliable and affordable method is required for analysis. In this article, a fast, robust, and reliable method is presented for routine, high-throughput drug screening of urine samples.

The isotopic profile of a material refers to the ratios of the stable isotopes of elements contained within, such as 2H/1H, 13C/12C, and 18O/16O. Biological, chemical, and physical processes cause variations in the ratios of stable isotopes; analysis of a material for its distinctive isotopic signature can thus be used to reveal information about its history. Isotope ratio mass spectrometry (IRMS) is a technique used to measure the relative abundance of isotopes in materials. Forensic investigators have used IRMS to measure a variety of materials, such as drugs, explosives, food, and human remains. In a recent web seminar, Lesley Chesson, the president of IsoForensics, Inc., explained how IRMS works and discussed the use of IRMS in forensic science, illustrating her discussion with several case examples.

This installment describes several commonly used microextraction sample preparation techniques and their applications to forensic toxicology analysis. Solid-phase microextraction (SPME), microextraction by packed sorbent (MEPS) and different types of liquid-based microextraction (LPME), including single-drop microextraction (SDME), hollow-fiber supported LPME, three-phase LPME, and dispersive liquid-liquid microextraction (DLLME), are discussed. Examples of application of these techniques to determine illicit drugs and drugs of abuse from various biological specimens are provided as well.

Populations worldwide are exposed to polychlorinated biphenyls (PCBs) that can be harmful to human health. LCGC spoke to David Megson from Ryerson University in Toronto, Canada, about recent developments in assessing human exposure to PCBs and chiral enantiomer fractions (EFs) in the workplace.

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With the ever-growing market for new drugs to enhance performance of horses, analysts are continually battling to develop new analytical methods to beat doping. LCGC spoke to Karen Y. Kwok from The Hong Kong Jockey Club in Hong Kong, China, about her work in this area.

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Populations worldwide are exposed to polychlorinated biphenyls (PCBs) that can be harmful to human health. The Column spoke to David Megson from Ryerson University in Toronto, Canada, about recent developments in assessing human exposure to PCBs and chiral enantiomer fractions (EFs) in the workplace.