Forensic Chemistry最新文献

The intentional release of Chemical, Biological, Radiological, and Nuclear (CBRN) material in conflict situations, terrorist attacks, or criminal acts poses a significant challenge to forensic investigations. The examination of CBRN incidents necessitates specialised methodologies due to the potential contamination of forensic evidence with CBRN materials. Focusing on forensic evidence, this paper reviews studies investigating the impact of chemical agents, biological materials, and ionising radiation on their recovery and enhancement. It provides an overview of forensic challenges in CBRN incidents, emphasising the intricate relationship between evidence recovery, decontamination strategies, and the preservation of forensic integrity. As CBRN incidents continue to pose threats, advancements in forensic science are imperative for effective investigations and the pursuit of justice. This paper explores the complexities surrounding incidents involving CBRN material, emphasizing the crucial role of forensic science in elucidating the modus operandi for effective event management and reconstruction. It is intended to offer the community of interest a concise overview of the potential difficulties and risks associated with handling CBRN-contaminated evidence, while also bringing attention to potential solutions.

Ante-mortem metabolic processes are responsible for the release of volatile organic compounds, which form the primary component of human scent and are used by search-and-rescue canines in victim location efforts. Similarly, the post-mortem processes of autolysis and putrefaction produce malodourous compounds that cadaver detection dogs use to locate human remains. This review examines literature on ante-mortem and post-mortem volatiles, with a focus on studies from 2010 onwards. A total of 973 different compounds were reported over this period, from the live matrices blood (65), breath (124), fingernails (17), hair (24), saliva (343), skin (385), sweat (37), urine (80), the whole body (86), and unspecified sources (31), and during early decomposition (321), middle decomposition (49), late decomposition (102), and an unspecified timeframe (113). There are notably more studies examining the matrices from living volunteers than decedents, and methods vary significantly between studies on living and deceased individuals in sampling methodology and analytical instrumentation. To establish a profile that accurately reflects the whole human volatilome, the standardisation of methodology and further research are required. Determining the complete human odour profile will assist in victim location where living and deceased individuals are commingled (e.g. disaster sites), and will inform future technologies to aid in accelerating search-and-rescue operations.

MillerCoors (MC) sued Anheuser-Busch (AB) over a 2019 advertising campaign emphasizing that Miller Lite and Coors Light beers are made with corn syrup. Because plants using the C4 photosynthetic pathway (corn, sugar cane, millet) are isotopically enriched in ¹³C, relative to ¹²C, in plants that use the C3 pathway (rice, barley, rye, wheat), carbon isotopes can provide relevant evidence. The plaintiff, MC, asserted 1) there is no corn syrup in the final product of Miller Lite or Coors Light; 2) they never use high fructose corn syrup (HFCS); 3) AB uses corn syrup as a fermentation aid in other products; and 4) AB adds HFCS to other product lines. I measured δ ¹³C_VPDB values for 27 beers, including the eight best-selling U.S. beers covering > 50% of the U.S. market. Miller Lite (−24.6 ‰) and Coors Light (−24.5 ‰) had 0–15% carbon from C4 sources, while Bud Light (−27.3 ‰), an AB product, had little to no C4 carbon. However, other AB products use more C4 carbon sources, including Bud Light Platinum (−22.0 ‰, 27 ±5% C4), Natural Light (−22.1 ‰, 26 ±5% C4), Category 5 Malt Hurricane (−21.1 ‰, 33 ±5% C4), Rolling Rock Extra Pale (−20.7 ‰, 37 ±5% C4), and Lime-A-Rita (−11.9 ‰, 98 ±4% C4). Corn syrup and HFCS were isotopically indistinguishable. This study supports claim 3, but cannot address claims 1, 2, and 4, highlighting both the utility and limitations of δ ¹³C measurements in ingredient identification in a civil case.

Forensic drug-testing laboratories worldwide are faced with the challenge of identifying a diverse and continuously changing collection of psychoactive substances. In the Netherlands, cathinone-type drugs are frequently encountered by the police. Since the ban on 3-methylmethcathinone (3-MMC) in 2021, the chlorinated analogs 3-chloromethcathinone (3-CMC) and 4-chloromethcathinone (4-CMC) increased in occurrence. In line with many ring-isomeric drugs, their identification is cumbersome due to similarities in their mass spectrum and typically require additional spectroscopic analysis for unambiguous identification. Although only three different isomeric forms exist, spectroscopic analysis by FTIR and NIR revealed four different spectral signatures. The fourth spectrum was attributed to a hydrated form of 4-CMC HCl that existed in parallel with its anhydrous form. This was confirmed by transformation experiments and chemometric modelling of mass spectra. The isomer 3-CMC was only observed in its anhydrous form, while 2-CMC was never observed in actual casework. Finally, MS-based differentiation of the three CMC-isomers was achieved by both a PCA (principal component analysis) and an LDA (linear discriminant analysis) model built from the 70 eV electron ionization mass spectral data. The LDA model correctly predicted the isomeric form of 50 casework samples by retrospective analysis of the recorded mass spectra. These findings show that chemometric modelling is an important tool to extract additional information from laboratory data that already was generated for routine analysis.

A known method of smuggling drugs into prisons is by infusing papers with these illicit substances, and sending them to prisoners through the mail. During the preparation of these drug-infused samples, there is potential for direct contact between the hands and paper, leading to the deposition of fingerprints. These fingerprints would not be visible to the naked eye, but can easily be rendered visible using the ninhydrin method for latent fingerprint detection. This reaction is well known to produce a visible purple coloured fingerprint on the surface of the material in a well-documented, consistent manner. This research, however, demonstrates variations of this reaction in the presence of illicit drugs on the surface of the paper being analyzed. The fingerprints have been demonstrated to vary in shade and intensity of colour in the purple/blue/grey region following the ninhydrin process when different drugs have been infused in the paper material. This phenomenon has the potential to be used as a presumptive indicator of any drugs that may be present in infused papers.

Use of immunoassay test strips for the detection of fentanyl in drug samples has become commonplace in harm reduction, law enforcement, public health, customs, and forensic science settings for testing drug product. With the recent increase of xylazine in the drug supply, use of xylazine test strips has also increased. As use of test strips expands, a desire to implement them for other drugs may emerge. However, since these strips are designed for urine testing, it is important to understand their applicability to testing drug product. In this work, we investigate the utility of seven types of urine immunoassay test strips – amphetamine, benzodiazepine, cocaine, methamphetamine, nitazene, opiate, and xylazine – for drug checking applications. Reproducibility, sensitivity, cross-reactivity, and the effect of prolonged exposure to elevated temperatures were studied. Generally, the tests were found to be reproducible, able to detect trace (µg/mL) levels of the analyte of interest, and minimally affected by prolonged storage at elevated temperatures. Nearly all tests showed cross-reactivity with compounds other than the analyte of interest, highlighting the need to better understand these limitations prior to implementation in a drug checking scenario. The viability of expired cocaine, fentanyl, and methamphetamine test strips was also interrogated, and little to no change in sensitivity was found even though the tests were multiple years expired.

Δ⁹-Tetrahydrocannabinol (Δ⁹-THC) is known to be the component of the cannabis plant responsible for the psychoactive effects generated by the activation of the endocannabinoid receptor 1 (CBR1). Following extensive structure–activity relationship (SAR) studies on Δ⁹-THC, new molecules with increased CBR1 affinity were designed and synthesized over the last decades. The knowledge arising from the pharmacological and synthetic investigations has been extensively used in the recent past by the industry of substances for recreational use also thanks to the 2018 Farm Bill Act in the USA and the incentive for low-THC cannabis (hemp) cultivation in Europe, which have boosted the availability of hemp derived precursors.

As a result, new semi-synthetic natural and pseudo natural cannabinoids related to the most famous Δ⁹-THC and often not subjected to legal restrictions are now available in the online market in a broad array of retail products with no preventive study on their pharmacodynamics and pharmacokinetics.

Some of these products (gummies, cannabis flower and a vape cartridge), all declared to contain the most potent among all the known cannabinoids, Δ⁹-Tetrahydrocannabiphorol (Δ⁹-THCP), were bought from an online shop and tested through LC-HRMS to determine the effective amount of Δ⁹-THCP and of other cannabinoids.

All the three samples were found to contain Δ⁹-THCP in amounts significantly different from those declared by the producer. Moreover, the application of an untargeted metabolomics approach (cannabinomics) enabled the identification of other cannabinoids including the emerging semi-synthetic hexahydrocannabinol (HHC) and tetrahydrocannabidiol (H4-CBD) together with byproducts of synthetic origin.

Condom lubricants have been shown to contain polydimethylsiloxane (PDMS) in over 95% of cases, but PDMS is difficult to analyze using standard GC–MS or LC-MS due to their size, apolarity and issues with solvents and plasticizers. Py-GC–MS was established as one of the more relevant analytical techniques for PDMS evidence analysis. However, different pyrolysis units and various GC columns are available for use Py-GC–MS. These two parameters are likely to significantly affect the repeatability, reproducibility and sensitivity of the analysis and, as such, affect the recovery of condom traces in casework. This work employed a resistively heated filament pyrolyzer and an isothermal oven pyrolyzer to investigate differences in the profiles generated by the pyrolysis units in the analysis of 4 condom lubricants. Similar experiments were performed using different columns, with the same pyrolyzers, to determine which gave optimal compound separation. This enabled assessment of the combinations in terms of the qualitative and semi-quantitative repeatability, allowing recommendations for optimized condom residue analysis. Results indicate that the use of a HP-5MS column, coupled to an isothermal oven pyrolyzer, is the optimal instrument configuration for condom residue analysis, based on repeatability, reproducibility and sensitivity of PDMS analysis.

A liquid chromatography ultraviolet (LC-UV) method, which used methanol as the organic solvent for both extraction and separation, was developed for hemp compliance testing. While published methods occasionally used methanol for separation, all of them used gradient elution which would cause baseline drifts and a subsequent high limit of quantification (LOQ), and only eight or less cannabinoids were included. Our method was characterized by a baseline separation of Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and Δ⁹-tetrahydrocannabinolic acid (Δ⁹-THCA) among nineteen cannabinoids in ten minutes and a calibration between 0.04 to 50 µg/mL, making it the most effective method validated so far. However, a reproducible separation of Δ⁹-THCA could not be achieved with the common formate buffer system, presumably due to its adsorption onto the C18 column which could be prevented by either using acetonitrile in the organic solvent that was widely undertaken by published methods or adding 0.1 % (v/v) trifluoroacetic acid in the aqueous solvent that was achieved only in this study. While similar problems were not reported by published methods, it was speculated that the problem could be common for all C18 columns, more or less, as the stationary phase in this study was di-isobutyl-n-octadecyl-silane without any polar imbedded moieties. Additionally, while quantification of Δ⁹-THC at 230 nm achieved good specificity, quantification of Δ⁹-THCA required 269 nm for acceptable specificity, which was verified by electrospray ionization time-of-flight mass spectrometry (ESI/TOFMS), indicating no false quantification and identification of Δ⁹-THC and Δ⁹-THCA, despite the observation of ten matrix peaks in the LC-UV chromatograms and identification of three untargeted/unknown cannabinoids by ESI/TOFMS in ten samples.

Human remains detection dogs (HRDDs) play vital roles in forensic investigations and search and rescue missions by detecting decomposing human remains. However, there is a lack of standardized training protocols globally. This study evaluates various ethically sourced HRDD training aids, including amputated limbs, blood, and teeth used by the Ontario Provincial Police (OPP). Expanding on prior research, this study assesses amputated limbs stored outdoors, bone, tissue, blood, and teeth. The volatile organic compound (VOC) profiles of these aids are compared to cadavers decomposing at the Research in Experimental and Social Thanatology (REST) facility. The results highlighted that the combined VOC profile from all HRDD training aid types demonstrates a 68% similarity to REST cadavers, emphasizing the potential benefit of exposing HRDDs to a diverse range of training aids. This is because the similarities in VOC profiles of individual training aid types (amputated limbs stored indoors, bone, blood, tissue, amputated limbs stored outdoors, teeth) with REST cadavers were lower than 68%. Teeth (without organic matter) were identified as the least ideal training aid for enabling dogs to detect cadavers based on VOC profiles and HRDD responses. However, training on teeth may be required for operational needs, particularly when HRDDs need to locate teeth during field searches. This study also highlights the effectiveness of using amputated limbs and blood together as they comprise a majority of the 68% VOCs found similar to the REST cadavers and elicit desirable HRDD responses to decomposition odor.