Method for Postmortem Quantification of Δ9-Tetrahydrocannabinol and Metabolites Using LC-MS-MS

Abstract

A specific, sensitive, fast and simple method for analysis of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-THC (THC-OH) and 11-nor-Δ9-THC-9-carboxylic acid (THC-COOH) in routine postmortem cases using LC-MS-MS was developed and validated. Prior to solid phase extraction, urine, stomach contents and bile were pretreated using alkaline hydrolysis, while blood and vitreous humor were pretreated with protein precipitation. The distribution of THC, THC-OH and THC-COOH were investigated in 31 postmortem cases that tested positive for cannabinoids. This revealed new information regarding the distribution of THC in stomach contents and vitreous humor. Alkaline hydrolysis was sufficient for the deglucuronidation of THC-COOH-glucuronide to its free form, THC-COOH, in urine, bile and stomach contents. However, the THC-OH concentration in bile reported in this study is considerably high compared to that of previous studies. In conclusion, including THC and its metabolites (THC-OH and THC-COOH) is crucial for any forensic toxicology detection method to most accurately determine the role of cannabinoids in deaths.