Quantitative detection of ketamine, norketamine, and dehydronorketamine in urine using chemical derivatization followed by gas chromatography-mass spectrometry
JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
Authors: Huang, MK; Liu, C; Li, JH; Huang, SD
Abstract
A repeatable and highly sensitive analytical method using gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring mode (SIM) is developed for the simultaneous detection of ketamine (KT), norketamine (NK), and newly introduced dehydronorketamine (DHNK) in urine. The test specimen along with the deuterium analogues as internal standards (IS): d(4)-KT for KT and d(4)-NK for NK/DHNK, was extracted on an automatic solid-phase extraction (SPE) apparatus. The extracted eluate then was dried and derivatized with N-methyl-bis(trifluoroacetamide) (CF3CONCH3COCF3, MBTFA). Finally, the cooled derivatized solution was directly injected into the GC-MS system for analysis. The proposed process achieves high sensitivity for the detection of KT, NK, and DHNK. Correlation coefficients derived from typical calibration curves in the range of 20-200ng/mL are 1.000 for KT and NK, 0.999 for DHNK. The limits of detection (LODs) and limits of quantitation (LOQs) are 0.5-1.0 and 1.5-3.0, respectively. The overall method recoveries of KT, NK, and DHNK are 82.2-93.4. The intra- and inter-day run deviations are smaller than 5.0%. The analytical scheme was also applied to the determination of KT, NK, and DHNK in 20 KT suspected urine specimens, and the results reconfirm that DHNK is a main metabolite of KT. (c) 2005 Elsevier B.V. All rights reserved.
A high-throughput method based on microwave-assisted extraction and liquid chromatography-tandem mass spectrometry for simultaneous analysis of amphetamines, ketamine, opiates, and their metabolites in hair
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
Authors: Chang, Yuan-Jhe; Chao, Mu-Rong; Chen, Su-Chin; Chen, Chih-Hong; Chang, Yan-Zin
Abstract
A total sample-preparation and analysis time of 50 min is required for the high-throughput method of hair analysis proposed in this paper. The method is applicable to analysis of drugs commonly used in Asia, and their metabolites-methamphetamine (MA), amphetamine (AMP), methylenedioxymethamphetamine (MDMA), methylenedioxyamphetamine (MDA), ketamine (K), norketamine (NK), dehydronorketamine (DHNK), 6-acetylmorphine (6-AM), morphine (MOR), and codeine (COD). Cut and weighed hair (10 mg) was incubated for 3 min with methanol-trifluoroacetic acid (TFA) during microwave-assisted extraction (MAE) at 700 W. The incubation solution was evaporated, the residue was reconstituted in deionized water-methanol, 99: 1 (v/v), and 20 mu L was injected on to a core-shell column (50x4.6 mm, 2.6 mu m particle size) for liquid chromatographic-tandem mass spectrometric (LC-MSMS) analysis. Gradient elution separation was performed in 8 min at a flow rate of 1 mL min(-1). No signal interfering with any of the analytes was found in fourteen blank hair samples from different sources. The limits of detection and quantification were 0.5 pg mg(-1) and 2.0 pg mg(-1), respectively, for MA, AMP, MDMA, MDA, K, NK, and DHNK, and 2.0 pg mg(-1) and 5.0 pg mg(-1), respectively, for 6-AM, MOR and COD. The linear range was between the LOQ and 1000 pg mg(-1), and the correlation coefficients were all greater than 0.999. Investigation of matrix effects revealed that all the analytes were suppressed by less than 20 % and the standard deviation (SD) was always less than 7 %. Recovery was always greater than 90 % and the SD for each compound was less than 6 %. Precision and accuracy for each analyte were within 15 %. Eight authentic hair specimens from known drug abusers were successfully analyzed. Compared with traditional overnight incubation methods, the rapid 3-min extraction time achieved similar or greater extraction yields. Sample preparation by MAE was a reliable procedure for extraction of the analytes from hair but substantially simpler and faster than other methods.