Thermo Fisher Scientific has produced an application note describing a sensitive and simple LC-MS/MS method for quantitative analysis of THC and THCCOOH in oral fluid for forensic toxicology laboratories.
Introduction
The goal of this study was to develop a sensitive and efficient method for simultaneous determination of THC and THCCOOH in oral fluid.
Results and Discussion
Limits of quantitation (LOQs) were defined as the lowest concentrations that had back-calculated values within 20%, RSD for five QC replicates within 20%, and the ion ratio between quantifying ion and confirmation ion within 20%. Using these criteria, the limit of quantitation was 10 pg/mL for THCCOOH and 0.5 ng/mL for THC in oral fluid.
Conclusion
A sensitive and efficient LC-MS/MS method for the simultaneous quantification of THCCOOH and THC in forensic toxicology laboratories was demonstrated. Both analytes were extracted from oral fluid using a simple and fast SPE method (no pre-conditioning, no evaporation, or reconstitution). The LOQ for THCCOOH was 10 pg/mL with ion ratio confirmation. Quantification of both analytes provides the opportunity to improve interpretation of cannabinoid OF results by eliminating the possibility of passive inhalation and providing markers of recent cannabis smoking.
