Simultaneous Analysis of 15 Synthetic Cannabinoids in Human Urine by Using Liquid-Chromatography Tandem-Mass Spectrometry

LC-MS/MS method for synthetic cannabinoids

Abstract

Synthetic cannabinoids became popular since 2004 among mind-altering drugs, called as “legal highs”, “designer drugs”, or "herbal highs”. They are sprayed on plants and used by smoking, vaporizing or inhalation. They act on the same receptors (CB1 and CB2) as Δ-9-THC (delta-9-tetrahydrocannabinol) and are much more potent on brain cells than THC. To overcome the legal obstacles new analogues of synthetic cannabinoids are produced continuously by changing their chemical formulas. Immunochemical methods for detecting cannabinoids are difficult to develop due to their substantial structural variety and cross-reactivity. Therefore, independent confirmation methods are usually required such as gas- or liquid-chromatography-mass spectrometry technics.

We developed a validated LC-MS/MS method for the analysis of 15 synthetic cannabinoids simultaneously in human urine and applied it to routine clinical and forensic toxicology cases. We studied the linearity, limit of detection and quantification, accuracy of repeatability and reproducibility, recovery and carry-over as validation parameters. We assessed all results in acceptable ranges. Bias and RSD values were less than ± 15% and below 15% respectively. Calibration curve was linear (r2=0.999) in the range of 1-20 ng/mL. LOD and LOQ were found between 0.7 - 1.07 and 2.19 – 3.56 ng/mL respectively.