Journal of analytical toxicology最新文献

There is a growing interest for quantification of drugs in capillary blood. Phosphatidylethanol (PEth) is a biomarker for alcohol intake measured in whole blood, thus making it a candidate for capillary sampling. Our laboratory has been running a method for PEth quantification in venous blood since 2016 and we aimed to expand this method to also include capillary dried blood spot (DBS) samples. Two 10 µL volumetric absorptive microsampling (VAMS) devices, Capitainer®B Vanadate and Mitra® were included in the method development and validated. Calibrators and quality controls were spiked during the automatic sample extraction without the VAMS devices present, making it possible to extract and analyze both types of VAMS samples in the same set-up. With the Mitra device all pre-established validation criteria were fulfilled in the measuring range 0.03-4.0 µM (21-2812 ng/mL), including method comparison with our venous blood method. Capitainer fulfilled all validation criteria, except for the accuracy of samples with PEth levels ≥ 0.5 µM (≥ 352 ng/mL) (deviation -17.1 to -20.5%). The correlation analysis between Capitainer and the venous blood results showed no constant bias, but an acceptable small proportional mean difference of -7.6%. Overall, the method validation results for both Capitainer and Mitra were considered acceptable. Both devices were found suitable for the analyses of PEth.

Identification of N,N-dimethylpentylone (DMP) in counterfeit "Ecstasy" and "Molly" tablets poses risk to public health due to its adverse effects. Little information is available regarding the pharmacological activity or relevant blood or tissue concentrations of DMP, and even less is known about other structurally related beta-keto methylenedioxyamphetamine analogues on recreational drug markets, such as N-propyl butylone. Here, a novel toxicological assay utilizing liquid chromatography-tandem quadrupole mass spectrometry (LC-QQQ-MS) was developed and validated for the quantitation of DMP and five related synthetic cathinones (eutylone, pentylone, N-ethyl pentylone (NEP), N-propyl butylone, and N-cyclohexyl butylone), with chromatographic resolution from isomeric variants and quantitation performed by standard addition. A forensic series of 125 cases is presented for DMP and related analogs, along with pharmacological activity assessments using monoamine transporter and mouse behavioral assays. The blood concentration range for DMP in postmortem forensic cases was 3.3-4,600 ng/mL (mean: 320±570 ng/mL, median: 150 ng/mL), whereas pentylone, the primary N-desmethyl metabolite of DMP, was identified in 98% of cases with a concentration range 1.3-710 ng/mL (mean±SD: 105±120 ng/mL, median: 71 ng/mL). N-Propyl butylone, a newly identified synthetic cathinone, was quantitated in seven cases (mean±SD: 82±75 ng/mL, median: 50 ng/mL, range: 1.7-200 ng/mL). DMP displayed potent uptake inhibition at the dopamine transporter (IC50=49 nM), with 100-fold weaker potency at the serotonin transporter (IC50=4990 nM). DMP was a locomotor stimulant in mice (ED50=3.5 mg/kg) exhibiting potency relatively similar to eutylone, N-ethyl pentylone, and pentylone. Our results show that DMP is a psychomotor stimulant associated with adverse clinical outcomes leading to death. Forensic laboratories must continue to update testing methods to capture emerging drugs, with specific emphasis on resolution and identification of isomeric species. Following the scheduling of DMP in early-2024, there could be an anticipated market shift towards a new unregulated synthetic stimulant to replace DMP.

Natural toxins present an ongoing risk for human exposure that requires a rapid and accurate diagnosis for proper response. In this study, a qualitative liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method was developed and validated for the detection of a large, diverse selection of natural toxins. Data-dependent acquisition was performed to identify compounds with an in-house mass spectral library of 129 hazardous toxins that originate from plants, animals, and fungi. All 129 compounds were spiked into human urine, extracted, and evaluated for spectral library matching. Of these, 92 toxins met the quality criteria and underwent validation in urine matrix based on American National Standards Institute guidelines. A generalized workflow for method expansion was developed and enables the rapid addition of relevant compounds to the established method. This LC-HRMS method achieves efficient detection of natural toxins in urine, and the created workflow can rapidly increase compound coverage via method expansion.

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.