Simultaneous determination of Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in oral fluid using isotope dilution liquid chromatography tandem mass spectrometry.

The detection and confirmation of cannabinoids in oral fluid are important in forensic toxicology. Currently, the presence of Δ(9)-tetrahydrocannabinol (THC) is used for the detection of cannabis in oral fluid. A low concentration of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THC-COOH) is found in oral fluid, which suggested a convenient and low-sensitivity confirmation assay can be used in a routine forensic laboratory. In this study, a highly sensitive isotope dilution liquid chromatography-tandem mass spectrometry method following dansylation was successfully developed for simultaneous determination of THC and THC-COOH in oral fluid. The dansylated derivatives dramatically demonstrated and enhanced the sensitivity of THC and THC-COOH. To avoid signal influenced by the matrix, a 5-min liquid chromatography gradient program was evaluated and optimized, which reduced the sample diffusion and caused sharp peaks (less than 12 s) and thus helped to achieve detection at a low level. The sensitivity, accuracy, and precision were also evaluated, and high quantitative accuracy and precision were obtained. The limit of quantitation of this approach was 25 pg/mL for THC and 10 pg/mL for THC-COOH in oral fluid. Finally, the method was successfully applied to eight suspected cannabis users. Among them, in six oral fluid samples THC-COOH was determined at a concentration from 13.1 to 47.2 pg/mL.

Development of a rapid and sensitive LC-MS/MS assay for the quantification of commonly abused drugs in Asia in a micro-segment of a single hair using microwave-assisted extraction and dansyl chloride derivatization.

A high-throughput method using microwave-assisted extraction, chemical derivatization and liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) was developed for the simultaneous analysis of illicit drugs and their metabolites, including amphetamine (AMP), methamphetamine (MA), methylenedioxy- amphetamine (MDA), methylenedioxy-methamphetamine (MDMA), morphine (MOR), 6-acetylmorphine (6-AM), ketamine (K), and norketamine (NK) in a micro-segment of a single hair (0.4 mm). In order to elevate the throughput and sensitivities of selected compounds, 3 min microwave-assisted extraction and 10 min derivatization with dansyl chloride (DC) were employed. After derivatization, all compounds except ketamine and norketamine were derivatized and enhanced the sensitivities significantly. Derivatives showed intense fragment ions and low background noise on DC-MOR, DC-6-AM, and four DC-amphetamine-type stimulants. The total sample preparation and analysis time was 50 min. The calibration range was from LOQ to 5000 pg/mg, the coefficient of determination was better than 0.997. Intra-assay precision and accuracy were generally less than 15%. Limits of detection ranged from 15 to 50 pg/mg, limits of quantitation ranged between 45 and 125 pg/mg. The matrix effect was better than 90%. The method was successfully applied to the analysis of actual hair samples collected from multi-drug abusers. This advanced method showed practicality in hair analysis and was suitable for the extremely insufficient sample.