Journal of analytical toxicology最新文献

Liquid chromatography-mass spectrometry (LC-MS) methods for detection of multiple drugs of abuse (DoA) in oral fluid (OF) samples are being implemented in many clinical routine laboratories. Therefore, there is a need to develop new multianalyte methods with simple sample pretreatment and short analysis times. The purpose of this work was to validate a method detecting 58 DoA to be used with two different OF sampling kits, the saliva collection system (SCS) from Greiner Bio-One and Quantisal from Immunalysis, using the same sample pretreatment and analytical method. A set of 110 samples collected with the SCS kit was further compared to an high-resolution mass spectrometry (LC-HRMS) method in another laboratory. The method was successfully validated, with precision and accuracy of ≤15% and z-scores of <2 for external controls. Using a sensitive LC-MS-MS instrument, the detection limits were <1 µg/l in neat oral fluid. In the comparative study between the LC-MS-MS and LC-HRMS methods using SCS samples, a good agreement was observed. Discrepancies were limited to lower concentration ranges, attributable to differences in cut-off thresholds between the methods. This work contributes to the development of LC-MS multianalyte methods for OF samples, which are suitable for clinical routine laboratories.

This study focused on the simultaneous detection of amphetamine, 3,4-methylenedioxy methamphetamine, morphine, benzoylecgonine, and 11-nor-9-carboxy-tetrahydrocannabinol in whole blood and dried blood spot (DBS). It is aimed to select a solvent mixture for liquid-liquid extraction technique employing liquid chromatography-tandem mass spectrometry (LC-MS-MS). The obtained DBS results were compared with the whole blood samples results. A simple, rapid, and reliable LC-MS-MS method was developed and validated for all analytes in whole blood and DBS. LC was performed on a Hypersil Gold C18 column with an initial gradient of 0.01% formic acid, 5 mM ammonium format buffer in water, and acetonitrile at 0.3 ml/min with 7.5 min runtime. A methanol:acetonitrile (40:60 v/v) mixture was selected for both matrices. Limit of quantitation (LOQ) values were 10-25 ng/mL; linear ranges were LOQ-500 ng/ml for all analytes; correlation coefficients were greater than 0.99, and all calibrator concentrations were within 20%. Analytical recovery in blood and DBS ranged from 84.9% to 113.2% of the expected concentration for both intra- and inter-day. Analytes were stable for 1, 10, and 30 days after three freeze/thaw cycles. It was determined that the variances of the results obtained with the two matrices in the comparison study were equal for each analyte, and the results were highly correlated (r = 0.9625). A sensitive, accurate, and reliable chromatographic method was developed to determine amphetamine, 3,4-methylenedioxy methamphetamine, morphine, benzoylecgonine, and cannabis, by performing the same preliminary steps with whole blood and dried blood spots. It was observed that the results obtained in these two matrices were compatible and interchangeable when statistically compared.

The long-term stability of drug concentrations in human plasma samples, when stored under normal laboratory conditions over several years, is important for research purposes and clinical re-evaluation, and forensic toxicology. Fifty human plasma samples from a former clinical trial were re-analyzed after storage at -20°C for 11 years. Plasma samples were extracted using solid-phase extraction. Isotope labeled sufentanil-d5 was used as internal standard. Sufentanil plasma concentrations were determined by ultra-performance liquid chromatography with gradient elution, followed by tandem mass spectrometry with electrospray ionization. The linear dynamic range was 25-2500 pg/mL, the limit of detection was 10 pg/mL, and the lower limit of quantification was 25 pg/mL. Intra- and inter-assay error did not exceed 6%. The deviation of the measured sufentanil plasma concentrations between the re-analysis and the first analysis was -63 ± 14% (mean ± SD). Therefore, sufentanil concentrations in human plasma were not stable in samples frozen at -20°C over 11 years.

A blind quality control (BQC) program in blood alcohol analysis was implemented at the Houston Forensic Science Center (HFSC) in September 2015. By mimicking authentic toxicology blood evidence, the laboratory can perform a concurrent evaluation of their technical and administrative casework procedures and test the accuracy and reliability of their volatile analysis method in a format that is blinded to the analyst. From September 2015 to November 2023, HFSC's Quality Division submitted 1228 antemortem whole-blood samples: 292 ethanol-negative samples and 936 ethanol-positive samples at 16 target concentrations (0.051, 0.080, 0.100, 0.110, 0.120, 0.130, 0.150, 0.160, 0.170, 0.180, 0.190, 0.200, 0.230, 0.240, 0.250, and 0.260 g/dL). A second, unopened blood tube in 168 of the 1228 BQCs was also analyzed after 721-1140 days: 24 ethanol-negative samples and 144 ethanol-positive samples at 5 target concentrations (0.080, 0.100, 0.130, 0.180, and 0.240 g/dL). All 316 ethanol-negative samples remained negative. After 42-758 days, the average (median, range) change in ethanol concentration of the 936 positive samples was -1.4% (-1.3%, -12.0% to +8.4%) with a statistically significant difference (P < .001) observed for the gradual decline in blood alcohol concentration (BAC) over time. The average BAC percentage differences per target concentration, ranged from -6.4% (-0.008 g/dL) to +5.7% (+0.011 g/dL), were within HFSC's current measurement uncertainty (9.4% at k = 3), showing no apparent correlation between the change in ethanol and the theoretical target concentration. As the analysis time between the two blood specimens from the same evidence kit extended, the loss in ethanol significantly increased (P < .001).

Background - Alcohol is the most abused substance in Western society, resulting in major economic losses and negative health consequences. Therefore, there is a need for a selective and robust detection method for alcohol consumption in various clinical and forensic settings. This study aimed to validate a mass spectrometry method for quantifying phosphatidylethanol (PEth) and perform retrospective data analysis from the patient population of a national reference laboratory.

Methods: Quantification of phosphatidylethanol in whole blood was accomplished using an LC-MS/MS assay. Isotopically labeled internal standard for the two PEth homologues was added to the whole blood specimen, followed by protein precipitation with a mixture of acetonitrile and isopropyl alcohol. After centrifugation, an aliquot of the supernatant was buffered with ammonium acetate before LC-MS/MS analysis on an Agilent 6470 triple quadrupole mass spectrometer coupled to an Agilent 1260 Infinity II LC system. This LC-MS/MS assay was validated for clinical use in accordance with CLSI guidelines.

Results: The analytical measurement range, 10 - 2000 ng/mL, was linear with R2 of 0.999. The within-run and total imprecision was < 5% CV for the low (20 ng/mL), medium (200 ng/mL), and high QC (1000 ng/mL). Results from accuracy and method comparison experiments met the bias criteria of ±15%. Retrospective data analysis showed ~27% of patients had PEth concentrations greater than 20 ng/mL. Males and females had similar positivity rates for PEth and the positivity rate of women of reproductive age (15-44 years old) was 35% in comparison to 25% in women 45-89 years old.

Conclusions: This study's LC-MS/MS method showed acceptable analytical performance in quantifying PEth as a sensitive and specific biomarker for evaluating alcohol consumption. Results from this study may provide an opportunity to educate women of reproductive age on drinking during pregnancy and the long-term effects of alcohol use.

In postmortem forensic investigation cases where the bladder is voided or dehydrated prior to autopsy, it is possible to wash the bladder with saline and collect the 'bladder wash' and any residual urine for toxicological analysis. While not conventional, this study aims to determine the use of bladder washes as alternative specimens in postmortem forensic toxicology. Comprehensive drug and alcohol analysis was performed on blood, urine, vitreous humor and bladder wash samples. Control studies consisted of matched bladder wash and urine samples for comparison. Authentic applicability studies were performed on bladder wash samples in cases where only blood or no urine samples were available. Bladder wash testing via the routine urine methodology were shown to have the appropriate sensitivity and specificity to serve as an alternative specimen. Specificity of the applicability studies was further improved when comparisons were corrected by evaluating individual analytes jointly with their related parent drug or metabolites. Individual and corrected sensitivity and specificity rates of above 99% were typically observed in both comparisons against urine and blood paired samples. Following drug analysis of 31 cases in which only a bladder wash was available, 57 detections from 23 different analytes were detected that otherwise would have not been obtained. This study demonstrates that standardized collection of the easily accessible bladder wash for postmortem toxicological analysis serves forensic toxicologists and pathologists with invaluable information where urine or other biological specimens are not available.

Opioids are widely prescribed pain medications that have the potential for misuse and abuse. As part of a routine procedure, our laboratory frequently encounters questions from clients/Medical Review Officers (MROs) regarding opioid hair concentrations in relation to the amount of opioid taken as part of a prescription. In this manuscript, we have analyzed a large number of real-world examples of opioid hair concentrations following self-reported consumption of an opioid prescription regimen. This dataset provides a reference point of opioid hair concentrations after an extensive aqueous wash that likely correspond to consumption of an opioid prescription regimen. Practitioners in the field could use this reference to make decisions on the opioid concentration of a hair sample in relation to a client-provided prescription.

Novel psychoactive substances (NPS) have historically been difficult compounds to analyze in forensic toxicology. The identification, detection and quantitation of these analytes and their metabolites has been difficult due to their rapid emergence, short life span and various potencies. Advancements in analytical instrumentation are fundamental to mitigating these NPS challenges by providing reliable identification and sensitivity. This review discusses the pros and cons of various analytical instruments that have played a pivotal role in NPS analysis. As analytical technology advanced, the ability to analyze for NPS became easier with high resolution mass spectrometry; however, traditional immunoassays are still beneficial for some NPS classes such as benzodiazepines. Over 200 articles from 2010-2023 were reviewed, and 180 were utilized for this review. Journal articles were categorized according to the technology used during analysis: immunoassay, gas chromatography mass spectrometry, liquid chromatography mass spectrometry-low resolution, and liquid chromatography mass spectrometry-high resolution to allow for quick references based on a laboratory's technologies. Journal articles were organized in table format to outline the authors, NPS drug classes, and instrumentation used, among other important information.

Carbon monoxide (CO) is a common gaseous toxin that causes severe poisoning symptoms. Accurate detection of the formation of carboxyhemoglobin (COHb) in the blood is very important for the identification of CO poisoning. In this review, the effects of exogenous toxins, including dichloromethane (DCM), nitrite and hydrogen sulfide, on the determination of COHb by spectrophotometry were summarized by comparing epidemiological data, case studies and analytical methods. The mechanism of the effects of these exogenous poisons on COHb detection is described, and the extent of their influence on the clinical diagnosis and forensic identification of CO poisoning is discussed. We suggest that emergency medicine and forensic science practices need to improve the understanding of these toxins, and optimize clinical diagnosis and evaluation strategies to address the effects of toxins on the determination of COHb.

As cocaine (COC) is not only incorporated into hair via blood following ingestion but also by external contamination, hair samples are commonly tested for COC metabolites to prove ingestion. However, COC metabolites can also be present as degradation products in typical street COC samples. The present study investigates minor hydroxycocaine (OH-COC) metabolites p- and m-OH-COC together with p- and m-hydroxybenzoylecgonine (OH-BE) in seized COC (n = 200) and hair samples from routine case work (n = 2389). Analytical results of hair samples were interpreted using an established decision model for the differentiation between actual use and external contamination using metabolic ratios (metabolite to COC). They were further examined concerning background of request, hair color, body site of sample collection, sex, and metabolic ratios of the main metabolites [benzoylecgonine (BE), norcocaine (NC), and cocaethylene (CE)]. All seized COC samples were positive for p- and m-OH-COC with a maximum percentage of 0.025% and 0.052%, respectively; p- and m-OH-BE were detected in 55% and 56% of samples with a maximum percentage of 0.044% and 0.024%, respectively. Analytical results of 424 hair samples (17.7%) were interpreted as being predominantly from contamination; the majority of these samples were from traffic medicine cases (83.7%). Metabolic ratios of minor OH-COC metabolites were significantly higher in hair samples interpreted as originating from use than in samples interpreted as caused by contamination. Metabolic ratios for OH-COCs were significantly higher in forensic cases compared to abstinence controls and also in black hair compared to blond/gray hair. However, this was not the case for OH-BE metabolic ratios. No statistical difference was observed with regard to the donor's sex. OH-COC metabolic ratios increased significantly with increasing ratios of NC and CE to COC, respectively. The study demonstrates that OH-COC metabolites (including thresholds for their metabolic ratios) must be used for a reliable interpretation of positive COC results in hair samples.