Method Development for a Sensitive and Reliable Quantification of 39 Total Cannabinoids and Their Metabolites by UPLC-MS/MS

The global expansion of medicinal and recreational cannabis use has increased interest in the occurrence, metabolism, and environmental fate of cannabinoids. Most analytical methods, however, target Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and only a limited subset of related compounds. In this study, a rapid UPLC-MS/MS method was developed and evaluated in standard solutions for the simultaneous determination of 39 cannabinoids and cannabinoid metabolites. Chromatographic and mass-spectrometric conditions were optimized, and calibration performance, bias, precision, carryover, detection capability, and chromatographic selectivity were assessed with reference to relevant elements of ANSI/ASB Standard 036. Thirty-eight analytes produced calibration coefficients of determination (R2) ≥ 0.990; 7-OH-CBD produced R2 = 0.975 and was retained as a provisionally characterized analyte because its bias and precision remained acceptable, although its calibration performance and LOQ (0.500 ng/mL) were inferior to those of the other analytes. Most critical isomeric pairs achieved baseline separation, whereas Δ9-THCV/Δ8-THCV was only partially resolved (Rs = 1.12). The present results establish a broad-panel method-development foundation in standard solutions. Matrix effects, extraction recovery, stability, dilution integrity, and internal-standard correction must be evaluated before quantitative application to biological, forensic, wastewater, or environmental samples.