Journal of analytical toxicology最新文献

The establishment of stringent identification criteria is essential for accurate reporting of toxicological drug testing, particularly in forensic settings involving medico-legal cases. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) is widely employed for its broad analyte coverage and high mass accuracy, yet limited published and validated identification criteria pose significant challenges for its use beyond presumptive screening in low case volume settings. This study characterized, optimized and selected LC-QTOF-MS identification criteria, assessing the influence of concentration, matrix and drug class on their performance. In addition to standard identification parameters, an effective combined weight score (CWS) threshold that emphasized library score and mass error was established. Higher analyte concentrations improved spectral reproducibility, while urine matrices introduced variability in isotope ratios and library scores. Authentic casework demonstrated 99.9% efficiency, 98.9% sensitivity, and 100% specificity, indicating a highly reliable method that achieves excellent accuracy, minimizes false positives as required for confirmatory techniques, and maintains sufficient sensitivity for effective screening of casework, thereby supporting robust and defensible forensic toxicology workflows. These findings also highlight the importance of refining LC-QTOF-MS specific identification criteria to enhance consistency and reliability in forensic toxicology reporting, and allows for reproducibility across other instrumentation, workflows, and fields.

This review is intended for forensic toxicologists and cheminformaticians seeking an understanding of the past implementations and future directions of artificial intelligence (AI) and machine learning (ML) for high-resolution mass spectrometry (HRMS) data interrogation in forensic toxicology. It provides a comprehensive overview of the data processing steps required to generate valid ML inputs, including molecular representation, augmentation, tokenization, embedding, and spectral deconvolution. We examine the advantages and disadvantages of different modeling strategies and summarize existing models from forensic toxicology and related domains. Applications are grouped into spectra-to-compound, compound-to-spectra, and classification models, with attention to recent advances and the practical challenges of limited data, polysubstance use, and validation. By leveraging advances from related fields, ML can enhance forensic HRMS workflows, enabling more efficient unknown screening, structural elucidation, and classification of emerging substances. This review aims to bridge disciplinary perspectives and support the practical integration of ML into routine forensic toxicology.

Nitrous oxide (N2O), the colorless, odorless gas known as "laughing gas", has gained recent attention for its misuse as a recreational drug. As an anesthetic, N2O produces sedation, euphoric and possible hallucinogenic effects. Adverse effects may include disorientation, psychomotor retardation, hypoxia, and asphyxia. N2O misuse has grown due to its ease of availability, rapid onset of effects, and increased social media attention, leading to anticipated increases in forensic testing needs. Due to its short half-life and volatility, analytical detection can be challenging. From January 2022 through September 2025, over 1700 cases were analyzed for N2O using headspace-gas chromatography-mass spectrometry (HS-GC-MS) over a calibration range of 1.8-180 mcg/mL. Total test requests and percent positivity increased during this timeframe for both driving (DUID) and postmortem (PM)/clinical casework. Blood, brain, liver, lung, and urine yielded positive detections. Attempts at repeat testing indicate significant losses in analyte concentrations. Consideration of pre-analytical and analytical factors are critical for suspected inhalant casework. Overwhelmingly, both DUID and PM casework noted N2O canisters present at the scene. Common driver behaviors included disorientation, slow reaction times, struggling with speech, inability to follow directions, and difficulty maintaining balance. DUID blood draws should be collected as close as possible to the suspected incident. Further review of case histories and testing practices generated handling recommendations for suspected inhalant case samples: fill containers to limit headspace; glass containers and tight-fitted closures are preferred; avoid transferring volume to alternate containers; limit container ingresses; and avoid repeat testing within the same container. Multiple matrices/containers should be collected and preserved, whenever possible, with inhalant testing prioritized over other drugs and/or alcohol. Laboratories should also consider qualitative reporting and/or testing as a one-time analysis. By employing these best practices, an inhalant gas may be better collected and preserved, increasing the chances of detection.

Assessment of drugs of abuse in biological fluids requires thorough knowledge of stability of the drugs under various conditions, including sample collection, handling, transportation, and analysis, to ensure accurate interpretation of results. This systematic review provides an overview of the literature on the pre-analytical stability of selected clinically relevant drugs of abuse in urine. A systematic search of the PubMed and Embase databases was conducted in October 2020 and February 2024. The search strategy encompassed over 20 drugs and their relevant metabolites tested in urine, focusing on studies that examined the stability of opioids, amphetamine-like drugs (including ephedrine, cocaine and cathinone), and cannabis using mass spectrometry. A total of 2,688 records were identified, and 71 studies met the inclusion criteria. These studies evaluated storage conditions including room temperature, refrigeration, freezing, and deep freezing, as well as the effects of freeze-thaw cycles. Most drugs demonstrated stability for months when refrigerated or frozen, and deep freezing and freeze-thaw cycles generally had minimal impact on stability. However, storage at room temperature showed limited stability, with cathinone, cannabis, morphine, codeine, and cocaine being particularly prone to degradation under different conditions. This review offers valuable insights into the storage stability of a wide range of drugs of abuse in urine, serving as a practical resource for healthcare professionals and others working with these substances in laboratory settings.

Purpose: This study aimed to develop a highly sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of propranolol and its metabolites in human biological samples. By analyzing their presence in urine, postmortem biological fluids, and various solid tissues, the study could be of reliable forensic toxicological use for investigations in propranolol poisoning cases. In this study, the Standard Addition Method (SAM) was used for quantification, and its validation was mixed with one of the analyte's concentrations.

Methods: A 0.1 mL aliquot of each body fluid sample or 0.1 g each of homogenized solid tissue was mixed with one of the analyte concentration standards, extracted with methanol, spiked with an internal standard (IS) using the SAM, and purified using magnesium sulfate and sodium sulfate. Following centrifugation and filtration, samples were analyzed via LC-MS/MS. Urine samples underwent enzymatic hydrolysis with sulfatase and β-glucuronidase to measure conjugated metabolite forms prior to analysis.

Results: Phase I metabolites (propranolol, 4-hydroxypropranolol, propranolol glycol, N-desisopropylpropranolol, 1-naphthylenyloxyacetic acid, and 1-naphthol) and phase II metabolites (sulfate and glucuronide conjugates) were identified in urine. Among postmortem samples, propranolol was highest in the bile, followed by the lung tissue. Naphthoxylactic acid could be consistently detected in all samples except for the brain, suggesting its potential as a good biomarker for propranolol exposure.

Conclusion: A validated LC-MS/MS method for determining propranolol and its metabolites in forensic samples was established, and it could also be applied to the authentic human samples obtained from a propranolol poisoning case. The findings could offer substantial and reliable support for investigating propranolol-related fatalities and contribute to the comprehensive understanding of the metabolism of propranolol in the human body.

Delta-8-tetrahydrocannabinol (Δ8THC) has been growing in popularity across the United States due to its reported therapeutic benefits, including pain relief, euphoria, and relaxation, and mild psychoactive effects, especially in areas where sale of delta-9-tetrahydrocannabinol (Δ9THC) is illegal. Currently, much debate surrounds Δ8THC regarding its regulatory status and whether this compound is safe and similar in pharmacokinetics to Δ9THC. To address the latter issue, a single-dose oral (7.5 mg/kg) and intravenous (IV; 1.25 mg/kg) pharmacokinetic study was performed in male Sprague-Dawley rats. A bioanalytical method was developed and validated following the FDA M10 guidelines in rat plasma to detect Δ8THC and its metabolites, 11-hydroxy-delta-8-tetrahydrocannabinol (11OH-Δ8THC) and 11-carboxy-delta-8-tetrahydrocannabinol (11COOH-Δ8THC). This method was then applied to analyze the plasma samples collected during the preclinical pharmacokinetic studies. The plasma concentration-time profiles were subjected to non-compartmental analysis (NCA) to obtain pharmacokinetic parameters. When administered intravenously, Δ8THC had a clearance of 5.6 ± 0.4 L/h/kg, a volume of distribution of 108.4 ± 8.9 L/kg, and elimination half-life of 13.9 ± 2.0 h. Δ8THC pharmacokinetic parameters following oral administration, exhibited a Cmax (peak plasma concentration) of 13.4 ± 0.9 ng/mL with a Tmax (time to reach Cmax) of 0.5 ± 0.1 h, and an oral bioavailability of 3.0 ± 0.3%. The clearance of Δ8THC when dosed IV is higher than rat hepatic blood flow (4.8 L/h/kg), indicative of extrahepatic clearance. Δ8THC also had a large volume of distribution, indicating extravascular distribution. Overall, Δ8THC had very low oral bioavailability, while the clearance and volume of distribution values indicate extensive tissue distribution with contribution of extrahepatic clearance.

Δ9-tetrahydrocannabinol (Δ9-THC)-dominant cannabis use can cause impairment and risks to workplace safety, which makes the detection of Δ9-THC in oral fluid (OF) important for workplace drug testing. However, cannabidiol (CBD)-dominant cannabis sold as legal hemp products (≤0.3% Δ9-THC) often contain some Δ9-THC. In the present study, participants self-administered 1.5 mL medium-chain triglyceride (MCT) oil containing 100 mg CBD and either 0, 0.5, 1.0, 2.0, 2.8 or 3.7 mg Δ9-THC twice daily for 14 days (n = 10/Δ9-THC dose condition), followed by a 7-day washout period. OF CBD, 7-hydroxy-cannabidiol (7-OH-CBD), 7-carboxy-cannabidiol (7-COOH-CBD), Δ9-THC, 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-Δ9-THC), and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (Δ9-THC-COOH) were measured by LC-MS/MS (cutoff 0.025 ng/mL). Median CBD peaked at 2,198 ng/mL 0.5 h after dosing, which likely reflects a high amount of direct oral cavity deposition, followed by a rapid decline. CBD pharmacokinetics were unaffected by the co-administration of Δ9-THC. CBD and Δ9-THC metabolite concentrations were low (<2 ng/mL), with some accumulation observed for 7-COOH-CBD with twice-daily exposure. After dosing with 100 mg CBD + 0.5 mg Δ9-THC, 1/10 participants had a positive OF test (≥2 ng/mL Δ9-THC) 1.5-6 h after a single acute dose. The rate of positive test results increased as Δ9-THC doses increased to 8/10 participants testing positive after acute doses of 100 mg CBD + 2.8 or 3.7 mg Δ9-THC. A consumer of hemp products might be unaware of the risk of a positive drug test as many products do not specify that they contain Δ9-THC. One positive sample was obtained at baseline, possibly due to direct oral cavity deposition of environmental contamination. Five samples in the CBD alone group, collected 0.5 h after dosing, were positive, likely due to minimal (0.02-0.15%) conversion of CBD to Δ9-THC during analysis. Laboratories are advised to take action to identify specimens where OF Δ9-THC results could be influenced by these factors.

Synthetic cathinones are a class of New Psychoactive Substances (NPS) with 3-chloromethcathinone (3-CMC) accounting for over 46% of NPS-related seizures in 2023. Sold as a racemate, 3-CMC exhibits enantioselective metabolism and pharmacological effects, making enantioselectivity a critical factor in evaluating its toxicokinetics and toxicodynamics. This study aimed to evaluate the enantiomeric biodistribution, metabolic profile, and toxicity of 3-CMC racemate in Wistar rats following acute exposure. For this purpose, a gas chromatography-mass spectrometry (GC-MS) method was validated for quantifying 3-CMC in biological matrices and for characterizing its biodistribution in vivo. Rats were intraperitoneally administered with saline (control) or 3-CMC (10 or 20 mg kg-1, b.w.). Animals were sacrificed 24 h after administration, and plasma, urine, and tissues were collected for biodistribution, biochemical, and histopathological analyses. 3-CMC was exclusively detected in the urine, along with three additional pairs of enantiomeric metabolites. Both 3-CMC and its metabolites exhibit enantiomeric fractions (EF) different from 0.5, indicating enantiomeric enrichment. Administration of 3-CMC significantly decreased plasma levels of creatine kinase-MB, alkaline phosphatase, and aspartate aminotransferase, along with increased levels of glucose and urea. In the urine, decreased levels of albumin were observed. Oxidative stress and energy biomarkers were altered in the brain, lungs, and kidneys. Histopathological analysis revealed morphological alterations in the brain, liver, and lungs at both doses, and in the kidneys at the highest dose. However, no significant alterations were observed in the other tissues. Taken together, our findings suggest enantioselective metabolism and indicate that, although rapidly eliminated by the kidneys, 3-CMC still causes significant toxicity in target organs, such as the brain, liver, lungs, and kidneys. This highlights the high toxicity of the drug or its metabolites, even over short-term exposure.