Simultaneous quantification of 11 cannabinoids and metabolites in human urine by liquid chromatography tandem mass spectrometry using WAX-S tips.

A comprehensive cannabinoid urine quantification method may improve clinical and forensic result interpretation and is necessary to support our clinical research. A liquid chromatography tandem mass spectrometry quantification method for ∆(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), ∆(9)-tetrahydrocannabinolic acid (THCAA), cannabinol (CBN), cannabidiol (CBD), cannabigerol (CBG), ∆(9)-tetrahydrocannabivarin (THCV), 11-nor-9-carboxy-THCV (THCVCOOH), THC-glucuronide (THC-gluc), and THCCOOH-glucuronide (THCCOOH-gluc) in urine was developed and validated according to the Scientific Working Group on Toxicology guidelines. Sample preparation consisted of disposable pipette extraction (WAX-S) of 200 μL urine. Separation was achieved on a Kinetex C18 column using gradient elution with flow rate 0.5 mL/min, mobile phase A (10 mM ammonium acetate in water), and mobile phase B (15 % methanol in acetonitrile). Total run time was 14 min. Analytes were monitored in both positive and negative ionization modes by scheduled multiple reaction monitoring. Linear ranges were 0.5-100 μg/L for THC and THCCOOH; 0.5-50 μg/L for 11-OH-THC, CBD, CBN, THCAA, and THC-gluc; 1-100 μg/L for CBG, THCV, and THCVCOOH; and 5-500 μg/L for THCCOOH-gluc (R (2) > 0.99). Analytical biases were 88.3-113.7 %, imprecisions 3.3-14.3 %, extraction efficiencies 42.4-81.5 %, and matrix effect -10 to 32.5 %. We developed and validated a comprehensive, simple, and rapid LC-MS/MS cannabinoid urine method for quantification of 11 cannabinoids and metabolites. This method is being used in a controlled cannabis administration study, investigating urine cannabinoid markers documenting recent cannabis use, chronic frequent smoking, or route of drug administration and potentially improving urine cannabinoid result interpretation.
Competing Interests: The authors declare no conflicts of interest.