Forensic Chemistry最新文献

With the lack of standardized validation protocols across the forensic chemistry community, validation of instrumentation can be a challenging and time-consuming task. However, this process is crucial to understanding the associated capabilities and limitations, especially for nascent technologies. Rapid GC–MS is one such emerging analytical technique being increasingly implemented in forensic laboratories due to its fast and informative screening capabilities. However, a full validation for forensic samples has yet to be published since its debut. This work presents the results of a comprehensive validation of a rapid GC–MS system for seized drug screening through the assessment of nine components: selectivity, matrix effects, precision, accuracy, range, carryover/contamination, robustness, ruggedness, and stability. Single- and/or multi-compound test solutions of commonly encountered seized drug compounds were used to assess method and system performance. Results met the designated acceptance criteria for a majority of components. For example, retention time and mass spectral search score % RSDs were ≤10 % for precision and robustness studies. Limitations were identified for components that did not meet the acceptance criteria (e.g., inability to differentiate some isomers). The study design is part of a larger validation package developed for rapid GC–MS that includes a validation plan and automated workbook. The template, available for adoption by laboratories, ultimately aims to reduce the barrier of implementation for rapid GC–MS technology.

Nitazene analogs are among the most recent and potent additions to the novel synthetic opioid (NSO) market, and new analogs continue to emerge. Seized drug analysis commonly utilizes gas chromatography-electron ionization-mass spectrometry (GC-EI-MS), so it is therefore imperative to understand how nitazene analogs behave under EI-MS conditions, and how substitution at various sites on the molecule may impact the resulting EI mass spectra. This study characterizes the EI fragmentation behavior of 20 representative nitazene analogs that contain differing substitutions and proposes rational mechanisms to explain the observed behavior.

A general EI fragmentation pathway for nitazene analogs was proposed, with the most common nitazene fragment ions being observed at m/z 86, m/z 107, m/z 58, and m/z 77. Characteristic ions were determined for different substitution groups, enabling the identification of diethyl, desethyl, pyrrolidine, and piperidine substitutions at the amine moiety, and different alkoxy chain lengths at the aromatic ring of the benzyl group. Mechanisms for the formation of these characteristic ions were proposed with the aid of isotopically labeled standards and high-resolution mass spectrometry measurements. To help with the interpretation of EI mass spectra for nitazene analogs, decision trees were developed that encompass the characteristic fragment ions observed for substitutions to the amine moiety and benzyl group, with additional criteria provided for substitutions to the benzimidazole moiety. This study summarizes the fragmentation patterns and characteristic fragment ions in the EI mass spectra of 20 representative nitazene analogs, which will aid the seized drug community in identifying novel nitazene analogs.

A variety of types and brands of pre-mixed small engine fuels (SEFs) were analyzed by gas chromatography-mass spectrometry (GC–MS) to determine their ignitable liquid composition. Additionally, many of these brands and fuel mixes were tested six years apart, first in 2018 and again in 2024, to determine if any formulation changes had occurred. All tested products were comprised of a range of isoparaffinic content, and most also contained at least one aromatic compound. One product marketed as a fuel treatment to fix ethanol-related issues contained 2-butoxyethanol. To determine Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) ignitable liquid detection canine (ILDC) response to the specific combination of ignitable liquids in these products, ILDC teams searched representative samples of the SEFs with no detection difficulty shown for the vast majority of these products. Reporting the ignitable liquid classification of SEFs would be dependent upon individual forensic science service provider (FSSP) protocols and the appearance of the ignitable liquid in casework data. The classification possibilities for these mixtures are discussed, including a case example of data resembling an SEF.

In forensic toxicology, scopolamine remains as one of the most challenging alkaloid in terms of analytical detection. Given its rapid elimination, the detection window in common matrices is short. Taking advantage of a real case of Brugmansia intoxication, a metabolic study was carried out. We report the real case of a 16-year-old boy admitted to an Emergency Unit after consumption at high school of a beverage made of Brugmansia dried flowers. The medical staff noticed agitation, mydriasis and tachycardia. Scopolamine and atropine were positively detected in biological fluids using liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS/MS). To better characterize the intake and identify metabolic biomarkers, we developed a data mining workflow specific to tropane alkaloids and applied it to the urine sample. This metabolic profile may be useful in providing analytical methods with a wider detection window particularly in drug-facilitated crimes (DFC). Scopolamine and atropine metabolites were predicted in silico with GLORYx freeware to assist in metabolite identification. The previously published metabolic pathways for scopolamine and atropine in mammals were studied as well. A total of fifteen phase I and II metabolites were tentatively identified for scopolamine, while one metabolite was detected for atropine. In addition, we identified some tropane alkaloids from the plant that were also metabolized. These metabolites can be used as biomarkers of exposure to Solanaceae plants and may also be useful to distinguish between natural product use and clinical therapy.

The most common method for the synthesis of synthetic cannabinoids with an indazole core utilizes methyl indazole-3-carboxylate as a starting material. However, this method commonly suffers from poor selectivity and low yield. In the current work, a method using indazole-3-carboxylic acid as the starting material was developed and successfully applied in the synthesis of nine synthetic cannabinoids and six of their metabolites. The method provided selective alkylation at the N1-position and resulted in overall yields in the range of 51–96 %. Five of the synthetic cannabinoids have not been reported in the literature and were synthesized in a proactive attempt to predict future SCs. All of the synthesized metabolites have previously been encountered in either in vitro studies or authentic urine samples. Hence, the method proved to be useful for production of SC metabolites, which are relevant for forensic toxicology. All synthesized compounds were characterized with NMR and LC-QTOF-HRMS.

Methamphetamine is one of the most abused drugs worldwide. Forensic laboratories have developed various methods to analyze methamphetamine for identifying and comparing seizures. These methods basically focus on the physicochemical properties of the methamphetamine molecule. Because methamphetamine is commonly distributed in its hydrochloride salt form, information on the crystalline state of methamphetamine could give new insight for forensic drug analysis. To grasp this information, we applied low-frequency Raman spectroscopy to methamphetamine hydrochloride. A laboratory-built low-frequency Raman microspectrometer was used for measuring low-frequency Raman spectra of optically pure and racemic methamphetamine hydrochloride. A mixture of methamphetamine hydrochloride with dimethyl sulfone, which is frequently added as a diluent to illicit methamphetamines, was also measured. An ab initio calculation was performed to assign peaks in the low-frequency spectra. The phonon modes of methamphetamine hydrochloride, and their changes induced by impurities are discussed. To the best of our knowledge, this is the first reported application of low-frequency Raman spectroscopy technique to methamphetamine hydrochloride.