It is often necessary for a United States-based forensic laboratory to distinguish cocaine-base from cocaine hydrochloride (HCl). A technique for forensic laboratories to differentiate these two forms of cocaine is Fourier-transform infrared spectroscopy (FT-IR), but FT-IR is unable to distinguish mixtures containing both free-base and HCl, particularly at less than 10% of one or both of these forms of cocaine in a mixture. X-ray Powder Diffractometry (XRPD) overcomes this limitation by differentiating compounds by their crystalline phases, producing a diffractogram derived from each substance's crystalline structure. Additionally, XRPD is nondestructive and requires minimal sample preparation.If adulterants contain alkaline compounds such as sodium bicarbonate, then cocaine HCl has the potential to convert into cocaine free-base. Controlled experiments show that XRPD is able to detect cocaine free-base in a mixture with cocaine HCl and sodium bicarbonate, with a detection limit of 10% (w/w) cocaine free-base. Subsequently, a series of cocaine HCl samples mixed with sodium bicarbonate were analyzed over 59 weeks at both room temperature and elevated temperatures at various humidities to determine if cocaine HCl converted to free-base. After two weeks, cocaine HCl had begun to convert to free-base when stored at 55 °C and 80% humidity. Similar conversion was observed for samples stored at 55 °C and ambient humidity after 24 weeks. Samples at ambient temperature and humidity showed signs of conversion to cocaine free-base after 47 weeks of storage. Overall, experiments demonstrated that storage conditions may lead to cocaine HCl conversion to cocaine free-base when mixed with sodium bicarbonate.
Simultaneous identification and quantification of illicit drugs can substantially reduce the reliance on multiple analytical instruments and lower operational costs. This study evaluates the capability of benchtop NMR spectroscopy for integrated qualitative and quantitative drug analysis. A 60 MHz benchtop NMR spectrometer was employed to examine blind and seized casework samples suspected to contain methamphetamine (MA) or 3,4-methylenedioxymethamphetamine (MDMA). Spectral data were processed using a novel peak-matching algorithm, followed by an approach based on Wasserstein distance and a quantum mechanical spectral analysis (QMSA) framework to enable simultaneous identification and quantification. The analytical performance of benchtop NMR was benchmarked against conventional techniques, with identification compared to FT-IR and GC–MS, and quantification compared to HPLC-UV and high-field NMR. The identification algorithm reliably identified the suspected drugs in all samples and detected associated adulterants in most cases. Quantitatively, for suspected drugs, the approach based on Wasserstein distance achieved a root mean square error (RMSE) of 3.8 mg analyte/100 mg sample and QMSA achieved 1.3, compared to 1.4 for HPLC-UV and 1.6 for high-field NMR. For seized samples, RMSE values relative to HPLC-UV were 3.8 for Wasserstein distance approach and 1.5 mg analyte/100 mg sample for QMSA. These results demonstrate that benchtop NMR can provide a rapid, cost-effective, and reliable analytical approach capable of simultaneous identification and quantification of analytes without the need for compound-specific calibration standards. This integrated approach demonstrates strong potential for forensic laboratories and harm-reduction centres conducting routine drug screening.
Nutritional supplements or Dietary Supplements are a broad category of heterogeneous products with a variety of ingredients and claimed benefits that are consumed by athletes for a number of purposes. Numerous doping cases have been reported worldwide as a result of the high frequency use of supplements in sports. Among the substances prohibited by the World Anti-Doping Agency (WADA), stimulants account for a substantial proportion of adverse analytical findings. Therefore, their reliable detection in nutritional supplements requires robust analytical strategies and sensitive instrumentation. This review critically evaluates the analytical methods developed for the detection and quantification of WADA-prohibited stimulants in nutritional supplements. A comprehensive literature search was performed using PubMed, Scopus, and Google Scholar to identify relevant studies published between 2010 and 2024. Eligible studies were systematically analysed and synthesised based on the analytical techniques and methodologies reported over the past 14 years for stimulant detection in nutritional supplements. The available evidence indicates that prohibited stimulants are frequently detected in nutritional supplements, particularly in products marketed for energy enhancement and weight loss. The analytical performance of the reported methods is comparatively evaluated with respect to their forensic applicability. Finally, the review highlights the need for continued advances in sample preparation, analytical workflows, and harmonized protocols to improve the detection of prohibited stimulants and reduce the risk of unintentional doping among athletes.
In this study, the impact of reducing the spacer group length from propyl to ethyl in our previously synthesized tellurium-containing fluorophore on its sensitivity and selectivity for detecting trinitrophenol (TNP) is investigated. This chain length modification significantly enhanced the performance of the fluorophore L, achieving detection up to around ∼207 ppb level. The fluorescence quenching study further revealed a notable shift from static to dynamic quenching, which could be attributed to the shorter spacer length facilitating more efficient collisional interactions during the excitation of L at 380 nm. The ethyl-spacer fluorophore L exhibited over 91% fluorescence quenching efficiency that indicates further enhancement of the host guest interaction between L and TNP. Contrary to this, L maintained its multi-mechanism based “turn-off” sensing, which includes photo-induced electron transfer (PET), electrostatic interactions, intermolecular hydrogen bonding, and the inner filter effect (IFE). Furthermore, L coated sensing strips is also developed to consider the practical applicability for on-site TNP detection, showcasing clear, concentration-dependent fluorescence detection. This study underscores the importance of spacer length in tuning quenching mechanisms and sensor performance, and positioning the ethyl-spacer fluorophore to obtain a highly sensitive and selective probe for TNP detection in real-world scenarios.
Reliable, targeted sampling and detection of chemical warfare agent (CWA) residues following explosive dissemination remains a critical challenge in forensic chemistry and chemical incident response. This study integrates controlled detonation experiments with quantitative residue and statistical analysis, demonstrating the importance of matrix-specific and complementary sampling approaches for accurate residue detection. Two physicochemically diverse CWA simulants, methyl salicylate and malathion, as analogues for sulfur mustard (HD) and VX, were applied to steel ball bearings using cotton-polyester fabric or cotton wool across three deposition methods to evaluate their influence on simulant retention following detonation. Residues were quantified by high-performance liquid chromatography (HPLC) to assess both retention and secondary transfer. Results show matrix-dependent residue behaviour, with fabric consistently exhibiting the highest retention of methyl salicylate (up to 6 mg/L), while non-porous materials such as ball bearings and plastic fragments generally retained minimal residues. Container fragments selectively retained malathion more effectively, consistent with differences in physicochemical properties. Secondary transfer was confirmed by the detection of residues on initially uncontaminated fragments. Statistical significance of retention and transfer trends was evaluated using binary logistic regression. Findings demonstrate that matrix characteristics, deposition method, and simulant physicochemistry strongly govern post-blast residue patterns of CWAs. Importantly, residual contamination on fragments remained sufficient to pose transdermal and/or inhalation hazards, given the extreme acute toxicity of VX, which exhibits an oral LD50 of 0.04 mg/kg. Overall, the study provides novel, quantitative insight into post-detonation behaviour, informing forensic sampling strategies, hazard management, and chemical, biological, radiological, and nuclear (CBRN) incident response.
Potassium chlorate is a common oxidiser that can be illicitly synthesised using everyday consumer products. Its prevalence in homemade explosive (HME) formulations makes it a recurring concern for forensic and investigative authorities. Despite this, limited research exists on the forensic characterisation of homemade potassium chlorate and the potential for source attribution based on the synthesis route. This study aims to address this gap by synthesising potassium chlorate from a range of hypochlorite-based products as well as safety matches, followed by a comprehensive analytical characterisation of the resulting products. Yields varied considerably depending on the source material, while chemical analysis revealed differences in impurity profiles. Techniques including ATR-FTIR spectroscopy, Raman spectroscopy, X-ray diffraction, and SEM-EDS were utilised to assess chemical composition. The findings demonstrate that homemade potassium chlorates may carry traces of their precursor materials and synthesis routes, highlighting the potential for these markers to assist in forensic comparison and source attribution. Future work will explore the application of chemometric approaches and ICP-MS analysis to further enhance discrimination based on trace elemental and multivariate patterns, with the ultimate goal of strengthening forensic intelligence capabilities related to chlorate-based HMEs.
Methamphetamine is the most trafficked synthetic drug, with a significant proportion of its production originating from the precursor ephedrine/pseudoephedrine. Ephedrine/pseudoephedrine have their own production pathways, with novel synthetic routes appearing in reports. An investigation into chiral and stable isotope profiling of a novel synthesis to ephedrine via a carbamate protection-methylation pathway involving a lithium aluminium hydride reduction of carbamate protected phenylpropanolamine was performed. The combination of S13C and S2H values may allow for discrimination from other reported ephedrine-based routes. Likewise, the combination of S13C and S2H values may allow for discrimination from another recently reported novel ephedrine/pseudoephedrine carbamate protectionmethylation pathway. The S13C values were not as negative compared to the previously reported carbamate protection-methylation pathway. An investigation into the fractionation of 13C found a smaller negative shift during the methylation step which may reflect the source of the carbon group that carries out the methylation. Diastereomeric analysis confirmed ephedrine is formed and no presence of pseudoephedrine. Chiral analysis confirmed reduction of the ephedrine formed racemic methamphetamine.
Latent fingerprints on fabrics constitute critical forensic evidence in crimes involving physical contact, such as sexual assaults, yet their development on porous and structurally complex textiles remains challenging. Although 1,2-indanedione is an effective reagent for fabric substrates, its performance is strongly dependent on specific fabric morphology and time since deposition (TSD). To address the limited quantitative and mechanistic understanding of these effects, this study systematically investigated 1,2-indanedione-based latent fingerprint development on cotton fabric with different yarn counts, focusing on how fabric structure and TSD-dependent residue dynamics affect reagent-residue interactions and visualization quality. The results demonstrated that fabric thickness, yarn diameter, fabric density, and TSD significantly affect development outcomes. A textile-specific modulation factor (omega) was established to describe the combined influence of fabric structural parameters, parameterize the influencing factors, and simplify the analytical complexity. Building on this, a mathematical correlation was developed that integrates fabric properties, TSD, and development performance. To validate the modulation factor identified by our parametric model, a machine learning classifier was developed for rapid fingerprint assessment, achieving 89.43% accuracy. Shapley additive explanations analysis further demonstrated that this predefined factor was the most influential feature, confirming its predictive power. This study establishes a quantitative research framework to evaluate the efficacy of 1,2-indanedione for developing latent fingerprints on fabrics and advances traditional fingerprint development methods toward a more predictable and optimizable forensic analytical paradigm.
The attribution of conflict-driven environmental contamination to specific military actions presents significant scientific and legal challenges. This paper establishes forensic geochemistry as a framework that integrates geochemical, isotopic, toxicological, and spatial data to establish direct causal links between warfare and environmental degradation. Soils in semi-natural geosystems serve as the primary environmental records of the transport and accumulation of war-related pollutants. We evaluate key groups of forensic markers, including nitroaromatic and nitramine explosives, heavy metals and metalloids (HM) from munitions and armor, and specific radionuclide anomalies. Furthermore, we demonstrate how targeted chemical analyses can be coupled with remote sensing, GIS-based battlefield reconstructions, and process-based conceptual models to identify the sources, pathways, and timing of contamination. By adapting indicator frameworks such as the DPSIR (DriverPressure-State-Impact-Response) model and environmental liability frameworks, this approach organizes complex geochemical patterns into admissible evidence for war-crime investigations and reparations. Drawing on contemporary examples from the Russia-Ukraine war, we outline practical strategies to differentiate military contamination from pre-existing industrial backgrounds. Ultimately, we propose strict evidentiary criteria and identify research priorities to strengthen the role of forensic geochemistry in international environmental law and post-conflict remediation.
This work reports on the background levels of organic and inorganic traces relevant to forensic explosives investigations in 127 civilian cars from Germany, the Netherlands, the United Kingdom, Belgium, Switzerland, Norway, and the United States of America, and in 16 Dutch police cars. Extracts were analysed with liquid chromatography – tandem mass spectrometry to detect and quantify six organic explosives: RDX, HMX, NG, TNT, ETN, and PETN. Ion chromatography – mass spectrometry was used to identify and quantify sixteen inorganic ions: chloride, nitrite, thiocyanate, nitrate, chlorate, phosphate, sulfate, perchlorate, lithium, ammonium, magnesium, potassium, calcium, sodium, strontium, and barium. Organic explosives are generally absent in both civilian and police cars, similar to the broader environment. Background levels of most inorganic ions were also consistent with those previously found in the environment and on human hands. Perchlorate, however, was detected in more than half of the investigated cars (67%), in vehicles from each participating country, and at relatively high levels of up to 123.9 μg per sample. The traces may originate from PVC stabilisers used in the upholstery of the car. Driving a new car can transfer similar amounts of perchlorate to the hands (>10 μg) as the handling of a Super COBRA 6 flash banger. Suspect contamination of perchlorate from flash powder in a police car is also possible, albeit at low levels (<1 μg) in realistic scenarios. These results warrant careful investigative procedures and forensic interpretation, especially when evidence is retrieved from, or has been in contact with a car.
Strontium isotope (87Sr/86Sr) analysis has become an important tool in forensic science for constraining human geographical origin and reconstructing mobility patterns. Human hair provides a unique isotopic archive due to its incremental growth and short-term temporal resolution. However, despite significant methodological advances, the forensic application of hair Sr isotope analysis remains limited by interpretative and practical challenges. This review critically evaluates recent developments in analytical techniques, isoscape construction, and integrative modeling approaches, while highlighting persistent issues related to exogenous contamination, behavioral variability, and incomplete reference datasets. Although advances in high-resolution techniques such as LA-MC-ICP-MS have improved analytical precision, the reliability of forensic interpretations continues to depend on effective pretreatment protocols and the quality of environmental baselines. Importantly, Sr isotope compositions in hair reflect the combined influence of multiple environmental and dietary Sr sources and therefore should be interpreted as indicators of integrated exposure rather than deterministic geographic fingerprints. Future progress will require standardized methodologies, expanded multi-isotope datasets, and probabilistic modeling frameworks that explicitly incorporate uncertainty. Under these conditions, hair Sr isotope analysis can develop into a more reliable tool in forensic investigations.
Disposable pencil graphite electrodes (PGE) were evaluated as an unmodified disposable platform for voltammetric determination of fentanyl (FEN) in human serum and urine. Square-wave voltammetry (SWV) and differential-pulse voltammetry (DPV) provided reproducible signals with low background current. The analytical response was optimized by screening buffer media over pH 4.00-10.00, where the highest peak current observed in phosphate buffer at pH 8.00. Under the optimized conditions, calibration plots were linear over 8.00 & times; 10-7-1.00 & times; 10-4 M, with limits of detection of 9.41 & times; 10-8 M (SWV) and 2.63 & times; 10-7 M (DPV). For biological sample applicability, separate calibration lines were constructed for both human serum and urine, confirming strong linearity and sensitivity. The method showed a moderately green profile and was practically suitable for repeated use in standard analytical workflows. Greenness assessment revealed strong precision and linearity in human serum but indicated matrix-related challenges in urine samples. To rationalize the pH-dependent electrochemical behavior, density functional theory calculations were performed for neutral and protonated fentanyl using the omega B97X-D/def2-TZVP level with a polarizable continuum model for water. Molecular docking (Auto-Dock Vina) indicated favorable binding to human serum albumin (HSA; PDB ID: 2BXD) with a predicted affinity of-9.01 kcal/mol, supporting potential matrix-related interactions. This proposed approach enables submicromolar FEN determination using a simple disposable electrode while providing computational insight that complements the experimental optimization.
Synthetic drugs pose a growing threat to public health and safety due to their rapid diversification, low production costs, and the ease of access to chemical precursors and reagents. Understanding the underlying synthetic processes is essential to support chemical intelligence and interventions targeting clandestine laboratories. While traditional targeted profiling relies on prior knowledge of substances and synthesis routes, untargeted approaches are crucial for emerging compounds whose synthetic pathways remain unknown. This study presents an untargeted analytical workflow integrating solid-phase microextraction headspace gas chromatography-mass spectrometry (SPME-HS-GC-MS) and liquid chromatography coupled to Orbitrap highresolution mass spectrometry (LC-HRMS) for comprehensive impurity profiling of seized drug samples. Data were processed using Compound Discoverer, enabling automated feature annotation through integrated databases (mzCloud, HighResNPS) and FISh Scoring for structural elucidation. Applied to three seized nitazene samples, the workflow highlighted differences in impurity profiles that are consistent with variations in synthetic conditions and processes. In addition to the main active compounds, several intermediates, oxidation products, and trace-level new psychoactive substances (NPS), including cychlorphine, were putatively identified. The latter finding is notable given recent international alerts concerning orphine-type opioids associated with severe intoxications. Overall, the proposed strategy demonstrates the capability of untargeted LC-HRMS profiling to identify crossproduction phenomena and previously unreported impurities, offering a data-driven tool for early detection of NPS and forensic chemical attribution of seizures.
Buried explosive devices have been a source of danger present in wars throughout history and in modern conflicts today. Efforts are continuously made to explore and improve upon various explosive detection methods to mitigate these devices. A common method employs detection canines, which are able to sniff out devices based on their emission of volatile organic compounds (VOCs), even at minute levels. When an explosive device is buried, VOCs travel through the soil to the surface. This process introduces sources of vapor loss, notably sorption to the soil, limiting vapor availability. However, there is a lack of quantitative evidence from studies on the influence of soil types in different environmental conditions. This study considers the impact of various burial conditions on the simulated burial of two explosive-related compounds: 2,4-dinitrotoluene (DNT), a degradant and contaminant from TNT, and 2,3-dimethyl-2,3-dinitrobutane (DMNB), a common taggant in C-4. Headspace solid phase microextraction (HS-SPME) was used to measure free volatiles at varying heights along a simulated burial temporally, providing quantitative evidence of the gaseous diffusion process. A driving force of vapor transport was confirmed to be evapotranspiration, as conditions with moisture and sunlight resulted in higher concentrations of analyte present. Additionally, stronger adsorption to soil indicated that environments with a higher sand content are likely to have more successful detection of buried explosives. Complementary canine olfactory trials were conducted for comparison to the laboratory study. This work points to environments where detection of a buried explosive device is more likely to be successful or limited.
The 2018 Agriculture Improvement Act provides the distinction between illicit marijuana and legal hemp based on a 0.3% O9-tetrahydrocannabinol (O9-THC) threshold. Consequently, forensic laboratories and regulatory agencies must implement analytical methods capable of qualitative identification and quantification of O9-THC. Analysis is further complicated by the complex matrix of Cannabis sativa L., which contains various cannabinoid isomers. While liquid chromatography-mass spectrometry (LC-MS) precludes cannabinoid decarboxylation and cannabinoid conversion limitations inherent to gas chromatography-mass spectrometry (GC-MS), O9-THC isomers remain nearly indistinguishable in both full scan and product ion mass spectra. This study characterizes 11 Cu-phosphine complexes to assess their ability to differentiate common cannabinoids found in cannabis plant material, as well as O9-THC isomers that may be sprayed onto plant material, based on the formation of characteristic precursor or product ions. Specifically, the preferential binding affinity of cannabinoids to [Cu (PPh3)2(ACN)2]BF4, in combination with oxidative products generated through Cu-catalyzed O2 activation, facilitates the formation of a characteristic ion at nominal m/z 915 for O9-THC and no observable complex for CBD, enabling full scan isomer differentiation and eliminating potential CBD interference for O9-THC quantitation. Similar behavior was observed for [Cu((R)-BINAP)(ACN)2]BF4 and [Cu(dppf)(ACN)2]BF4. A methanolic extract of an authentic cannabis sample was analyzed using the optimal Cu-phosphine complexes to evaluate applicability to real-world samples. By demonstrating the potential of Cu-phosphine ion complexation and introducing a novel approach to eliminate CBD interference, this study establishes the foundation for future research distinguishing illicit marijuana from legal hemp, potentially strengthening the capabilities of marijuana identification within forensic laboratories.
Automotive vinyl wraps are an increasingly more common vehicle surface material that may be encountered as trace evidence in investigations. Despite their growing prevalence, no framework for the examination of vinyl wrap materials by vibrational spectroscopy has been established. This study used attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy in combination with partial least squares discriminant analysis (PLS-DA) to classify automotive vinyl wrap samples. Vinyl backing and adhesive layers were examined from commercial vinyl wrap samples representing various manufacturers, colors, and surface finishes. Principal component analysis demonstrated complete inter-class separation for ATR-FTIR backing spectra while Raman spectroscopy provided complementary discrimination driven primarily by inorganic pigment composition. PLS-DA roll level classification models achieved overall accuracies of 77%, 73%, 70%, and 45% for the ATR-FTIR adhesive, ATR-FTIR backing, Raman backing, and Raman adhesive models, respectively. Misclassifications were predominantly confined to within-class roll-level confusions rather than between product classes. Sequential examination of all four confusion matrices revealed that the combined analytical workflow reduced the number of indistinguishable sample pairs to a single within-class misclassification.
Naked-eye detectable reversible colorimetric method for latent fingerprints visualization was developed by utilizing base-responsive organic compounds, tetraphenylethylene (TPE) and triphenylamine (TPA) functionalized mono-quaternized 4,4 '-bipyridinium derivatives, 1-(2-oxo-2-(4-(1,2,2-triphenylvinyl)phenyl)ethyl)-[4,4 ' bipyridin]-1-ium bromide (TPE-MQ) and 1-(2-(4-(diphenylamino)phenyl)-2-oxoethyl)-[4,4 '-bipyridin]-1-ium bromide (TPA-MQ). TPE-MQ and TPA-MQ structures contains acidic methylene group, which showed high reactivity with base (ammonia (NH3)), resulting in the formation of increased it-conjugated enol structure. The formation of enol structure with increased conjugation transformed the colorless TPE-MQ and TPA-MQ to intense blue color both in solution and solid-state. The enol structure and intense color self-reversed to colorless keto form with time. The robust generation of color by base exposure were employed to detect latent fingerprints on various porous and non-porous surfaces using the powder dusting method. The colorless TPE/TPA-MQ powders were spread uniformly on the fingerprint marks. The exposure of ammonia vapor onto fingerprint marks produced naked-eye detectable distinct purple color. The digital colorimetric images clearly revealed information up to level two, including loops, lakes, short ridges, spurs, dots, and pores of fingerprint marks. Interestingly, the purple color of fingerprint marks disappeared within 30 min and becomes colorless. The re-exposure of ammonia generates fingerprint marks with purple color again, which indicated the possibility of concealment of information and read when it required. The facile naked-eye detectable and hideable colorimetric latent fingerprints method may be of potential interest in forensic science and criminology.
The castor bean plant, Ricinus communis, grows wild throughout many regions of North Africa. The seeds of the plant contain the Schedule I chemical agent ricin, which is a type II ribosome-inactivating protein. Currently, there is significant forensic interest in these seeds to enable source attribution. In this study, Liquid Chromatography-High Resolution Mass Spectrometry (LC-MS/HRMS) was used to analyze seeds collected from five regions across three North African countries, along with four known and well-characterized cultivars. The data were further processed using multivariate statistical analysis, which led to the identification of potential provenance specific ions. The approach was rigorously validated through both internal cross-validation and external blind testing. Extracts from blind specimens were included as a prediction set and were correctly classified by provenance and cultivar, even when different ricin extract preparation methods were used, achieving 100% overall prediction accuracy. This work confirms the relevance of LC-MS/HRMS-based metabolite fingerprinting for forensic attribution and demonstrates that such an approach, when supported by a proper chemometric workflow with internal and external validation, can achieve high classification performance. It also emphasizes the importance of further inter-laboratory efforts to validate specific marker ions and improve geographic representativeness.
