Simultaneous determination of ketamine, tramadol, methadone, and their metabolites in urine by gas chromatography-mass spectrometry.

An automated solid-phase extraction procedure combined with gas chromatography-mass spectrometry methodology, without derivatization, has been developed for the identification and quantitation of ketamine, norketamine, tramadol, methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, and 2-ethyl-5-methyl-3,3-diphenylpyrroline in urine. The analytical approach is simple and rapid, yet reliable. Good linearity (r(2) > 0.995 over the concentration range of 30 to 600 ng/mL), sensitivity (limits of quantitation 15-30 ng/mL), accuracy (81.0-109.9%), precision (RSD < 13.8%), and recovery (> 79.6% in average) were achieved for all analytes. Ninety-one urine specimens from suspected drug users and 21 clinical urine specimens from methadone substitution therapy patients were analyzed to validate the method compatibility and stability. Results have demonstrated that this GC-MS method is a good confirmation and quantitation test scheme for the six target compounds in urine.

GC-MS quantification of ketamine, norketamine, and dehydronorketamine in urine specimens and comparative study using ELISA as the preliminary test methodology.

An automated solid-phase extraction procedure combined with the gas chromatography-mass spectrometry (GC-MS) methodology, without derivatization, has been developed for the determination of ketamine (K), norketamine (NK), and dehydronorketamine (DHNK) in urine. The analytical approach is simple and rapid, yet reliable, achieving good linearity (r(2)>0.999 over the concentration range of 30 to 1000 ng/mL), sensitivity (limits of quantification = 15, 10, and 20 ng/mL for K, NK, and DHNK, respectively), accuracy (90-104%), and precision (RSD<8.1%) for all analytes. Two hundred and six urine specimens collected from suspected drug users were analyzed by this protocol and also screened by Neogen ELISA method to evaluate the efficiency as well as the compatibility of these two methods. Neogen ELISA showed high efficiency (98.1%), high sensitivity (90.9%), high specificity (98.9%), low false-positive rate (1.1%), and moderate false-negative rate (9.1%), adopting 10 ng/mL K as the cutoff. Neogen ELISA screening followed by GC-MS analysis appeared to be a good screening-confirmation test scheme for the analysis of K in urine. Twenty of the 22 positive urine specimens contained all three analytes simultaneously, with DHNK showing the highest and K the lowest concentrations.

Performance characteristics of DRI, CEDIA, and REMEDi systems for preliminary tests of amphetamines and opiates in human urine.

Arrestee urine specimens (930) were tested with DRI, CEDIA, and REMEDi; those that tested positive for amphetamines and opiates (616 and 414, respectively) were then confirmed by gas chromatography-mass spectrometry. The performance characteristics of these three preliminary systems were evaluated using the following commonly used parameters: true positive, true negative, false positive, and false negative. The sensitivity, specificity, and efficiency of these methods were also calculated. Data derived from this study indicated DRI and CEDIA adapted by this study generated acceptable preliminary test results for amphetamine/methamphetamine and morphine/codeine, but not for MDA/MDMA and REMEDi has lower sensitivity than DRI and CEDIA, but with better specificity and efficiency, supporting its use under emergency room settings where drug concentrations in overdose cases are expectedly at high levels.