Quantitative screening for benzodiazepines in blood by dual-column gas chromatography and comparison of the results with urine immunoassay.
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A dual-column retention index method is described for quantitative gas chromatographic (GC) screening of 26 benzodiazepine drugs and metabolites in the blood using DB-5 and DB-17 capillary columns and electron capture detection. The method involves a one-step, small-scale liquid-liquid extraction with ethyl acetate and derivatization with N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide with 1% tert-butyldimethylsilyl chloride. The results from the GC screening of 514 postmortem blood samples were compared to those obtained from urine immunoassay (Syva ETSplus with a 200-ng/mL cutoff). Both methods gave a negative result in 284 cases and a positive result in 149 cases. In 48 cases, urine was negative by immunoassay but blood was positive by GC. The opposite situation (blood negative, urine positive) was detected only in four cases. In 29 cases, an invalid result was obtained by urine by immunoassay: 26 blood samples of those cases were negative and three samples positive by GC. In postmortem forensic toxicology, the present GC method seems to be a good alternative to the common combination of urinary immunoassay followed by quantitative analysis of blood by chromatography. (+info)
Cocaine, cocaine metabolite, and ethanol concentrations in postmortem blood and vitreous humor.
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The use of postmortem cocaine and metabolite concentrations is a complex subject. This study was undertaken to determine (1) the usefulness of vitreous humor as a specimen, compared with blood, to quantitate cocaine and cocaine metabolites; (2) whether there is a preferential site of disposition for cocaethylene between vitreous humor and blood; and (3) if the presence of cocaethylene influences the concentration of benzoylecgonine in postmortem specimens. Cocaine, benzoylecgonine, and cocaethylene were quantitated in blood and vitreous humor by gas chromatography-mass spectrometry, and ethanol was quantitated by gas chromatography in 62 medical examiner cases. No differences were found between mean concentrations of vitreous cocaine 0.613 mg/L (standard deviation [SD] 0.994 mg/L), cocaethylene 0.027 mg/L (SD 0.59 mg/L), and ethanol 0.092 g/dL (SD 0.13 g/dL) compared to blood cocaine 0.489 mg/L (SD 1.204 mg/L), cocaethylene 0.022 mg/L (SD 0.055 mg/L), and ethanol 0.058 g/dL (SD 0.91 g/dL), respectively. However, a statistical difference was found between mean benzoylecgonine concentrations in vitreous 0.989 mg/L (SD 1.597 mg/L) and blood 1.941 mg/L (SD 2.912 mg/L) (p = 0.0004). Regression analysis demonstrated that linear relationships were present between concentrations of vitreous and blood cocaine (r = 0.854) and benzoylecgonine (r = 0.763). However, the correlation coefficients were lower for cocaethylene (r = 0.433) and ethanol (r = 0.343). There were variations between the concentrations of cocaine and metabolites both in terms of magnitude and also direction of change. Mean concentrations of benzoylecgonine in blood and vitreous were higher in cases where ethanol was absent, 2.593 mg/L (SD 3.195 mg/L) and 1.431 mg/L (SD 2.021 mg/L), compared to when ethanol was present, 1.199 mg/L (SD 2.396 mg/L) and 0.469 mg/L (SD 0.553 mg/L). This study demonstrates that vitreous humor may be used to quantitate cocaine and cocaine metabolites; however, because the concentrations of cocaethylene in vitreous humor and blood were not well correlated, vitreous humor may not be a reliable specimen for measuring cocaine and cocaine metabolite concentrations. (+info)
Use of solid-phase microextraction (SPME) for the determination of methadone and its main metabolite, EDDP, in plasma by gas chromatography-mass spectrometry.
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A simple, rapid method for the determination of methadone and its metabolite 2-ethylene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in plasma using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry is proposed. A 100-microm polydimethylsiloxane film fiber was exposed by immersion for 30 min in a diluted plasma solution (1:4 with buffer pH 9) containing both compounds and an internal standard (proadifen). Calibration curves were linear over the concentration range 50-2000 ng/mL. The analysis time was 45 min per sample. The determination of methadone and EDDP was subject to no interference. The performance of SPME was compared with that of liquid-liquid extraction, obtaining lower limits of detection for EDDP. The method using the two extraction procedures was applied to 10 plasma samples from methadone-treated patients. (+info)
Toxicological screening in trauma.
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OBJECTIVES: To determine the prevalence and patterns of alcohol and drug use in patients with major trauma. METHODS: Consecutive trauma patient enrollment, 24 hours a day, was envisaged with anonymised patient data on gender, age band, and mechanism of injury collected. The study group had surplus plasma quantitatively analysed for ethanol concentration, and urine samples were initially screened, via immunoassay, for opiates, cannabinoids, amphetamines, benzodiazepines, cocaine, and methadone. Confirmation and specification of individual positive results was then performed using thin layer or gas-liquid chromatography. Drugs of treatment given in the resuscitation room, if subsequently detected in the urine samples, were excluded from the final results. RESULTS: There were 116 eligible trauma patients assessed and treated in the resuscitation room over a six month period, of which 93 (80%) were enrolled. Altogether 27% of this trauma population had plasma ethanol concentrations greater than 80 mg/dl. There was a significantly higher prevalence of alcohol intoxication in the group not involved in a road traffic accident (RTA) compared with the group who were involved in a RTA. Initial screening of urine for drugs revealed a prevalence of 51%. After 12 exclusions due to iatrogenic administration of opiates, the final confirmed prevalence was 35% in this trauma population. The individual drug prevalence was 13% for cannabinoids, 11% for codeine, 8% for morphine, 6% for amphetamine, 6% for benzodiazepines, 3% for cocaine, 1% for dihydrocodeine, and 1% for methadone. CONCLUSIONS: There is a notable prevalence of drug and alcohol use in this British accident and emergency trauma population. A significantly higher prevalence for alcohol intoxication was found in the non-RTA group compared with the RTA group. The patterns of drug usage detected reflect local influences and less cocaine use is seen compared with American studies. The association between alcohol, drugs, and trauma, together with ethically acceptable methods of screening, are discussed. (+info)
Detection of drug misuse--an addictive challenge.
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It is now accepted that drug misuse is a large and growing problem in the United Kingdom, some estimates of the number of regular illicit drug users being as high as three million. The aim of this paper is to provide insight into the methods used to detect drug misuse. The strategy adopted by one laboratory is described and methods of screening for, and identification of, a wide range of compounds are provided. No claim is made that this is the best approach or that the list of drugs detected is comprehensive; the range of drugs encountered is always increasing and the lists are constantly updated. It is hoped that users of toxicology laboratory services will gain an appreciation of the capabilities and limitations of the techniques available; and that those who may wish to provide such a service will find the necessary information in a readily accessible format. (+info)
Rapid confirmation/quantitation of cocaine and benzoylecgonine in urine utilizing high performance liquid chromatography and tandem mass spectrometry.
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A rapid, but sensitive and selective method for confirmation and quantitation of benzoylecgonine (BZE) and cocaine (COC) in urine by fast-gradient liquid chromatography/tandem mass spectrometry (LC/MS/MS) is described. The chromatographic separation was performed on a reversed phase column employing fast-gradient techniques. Matrix prepared standards, blanks, and QC's were filtered then aliquots were transferred into a 96 well plate. Injection volumes of 25 microL were made onto the analytical column, with the flow diverted from the atmospheric pressure ionization source for the first 0.5 min of the analysis. Simultaneous multiple reaction monitoring (MRM) of three discrete transitions for each compound were used to identify BZE and COC. Quantitation was achieved utilizing the most prominent parent-daughter transition and internal standard calibration techniques. The coefficients of variation (CV) for the analysis of these drugs ranged from 0.6% to 6.8% at a concentration of 150 ng/mL (n = 155). This method suggests that fast-gradient LC/MS/MS may be suitable for routine confirmation of immunoassay cocaine-positive samples. (+info)
Analysis of underivatized amphetamines and related phenethylamines with high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.
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Amphetamine, methamphetamine, illicit designer phenethylamines (MDA, MDEA, MDMA, MBDB, and BDMPEA), and other phenethylamines (benzyl-1-phenylethylamine, cathinone, ephedrine, fenfluramine, norfenfluramine, phentermine, 1-phenylethylamine, phenylpropanolamine, and propylhexedrine) were extracted from serum using a solid-phase extraction procedure. The extracts were examined with high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS). The drugs were separated on ODS column in acetonitrile/50 mM ammonium formate buffer (pH 3.0) (25:75) as a mobile phase. Full-scan mass spectra of drugs examined by means of APCI with collision-induced dissociation showed protonated molecular ions and fragments typical for particular drugs. LC-APCI-MS allowed an unequivocal differentiation of all drugs involved. The quantitation was performed using selected ion monitoring of protonated molecular ions and fragments of drugs involved and their deuterated analogues. The limits of detection ranged from 1 to 5 microg/L serum, and the recoveries ranged from 58 to 96%. A linear response was observed for all drugs in the range from 5 to 500 microg/L. The method was applied for routine determination of amphetamine, MDMA, MDA, and MDEA in one run. Solid-phase extraction used assured simultaneous isolation of various groups of basic drugs of forensic interest (opiates, cocaines, phenethylamines, and benzodiazepines) from biofluids. (+info)
Fatal poisoning with a new phenylethylamine: 4-methylthioamphetamine (4-MTA).
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There has been much publicity in the United Kingdom regarding a new phenylethylamine-based compound called 4-methylthioamphetamine (4-MTA), also known as para-methylthioamphetamine (p-MTA), MTA or "Flatliner". Chemically, 4-MTA is an amphetamine derivative and is a non-neurotoxic potent serotonin-releasing agent and reversible inhibitor of rat monoamine oxidase-A. Analysis of postmortem blood and urine specimens in a case implicating 3,4-methylenedioxymethamphetamine revealed the presence of 4-MTA at a concentration of 4.6 mg/L in femoral blood and 87.2 mg/l in the urine. The concentration of 4-MTA in perimortem blood was measured at 4.2 mg/L. This is the first reported case of death involving 4-MTA in the United Kingdom and the first case known to involve 4-MTA only. (+info)