In hair analysis, identification of 11-nor-9-carboxy-Δ 9 -tetrahydrocannabinol (THC-COOH), one of the major endogenously formed metabolites of the psychoactive cannabinoid tetrahydrocannabinol (THC), is considered unambiguous proof of cannabis consumption. Due to the complex hair matrix and low target concentrations of THC-COOH in hair, this kind of investigation represents a great analytical challenge. The aim of this work was to establish a fast, simple, and reliable LC-MS 3 routine method for sensitive detection of THC-COOH in hair samples. Furthermore, the LC-MS 3 method developed also included the detection of derivatized 11-hydroxy-Δ 9 -THC (11-OH-THC) as an additional marker of cannabis use. Hair sample preparation prior to detection of the two THC metabolites was based on digestion of the hair matrix under alkaline conditions followed by an optimized liquid-liquid extraction (LLE) procedure. Sample preparation by LLE proved to be more suitable than solid-phase extraction (SPE) due to less laborious and time-consuming steps while still yielding satisfactory results. A significant improvement in analytical detection was introduced by multistage fragmentation (MS 3 ), which led to enhanced sensitivity and selectivity and thus low limits of quantification (0.1 pg/mg hair). The MS 3 method included two transitions for THC-COOH (m/z 343 ! 299 ! 245 and m/z 343 ! 299 ! 191) encompassing the quantifier (m/z 245) and the qualifier ion (m/z 191). The method was fully validated, and successful application to authentic toxicology case samples was demonstrated by the analysis of more than 2000 hair samples from cannabis users with THC-COOH concentrations determined ranging from 0.1 to >15 pg/ mg hair.

Since their first appearance in 2008, synthetic cannabinoid receptor agonists (SCRAs) remain the most popular new psychoactive substances (NPS) in the EU. Following consumption, these drugs and their metabolites are urinary excreted and enter the sewage system enabling the application of wastewater‐based epidemiology (WBE). Knowing the fate of target analytes in sewage water is essential for successful application of WBE. This study investigates the stability of several chemically diverse SCRAs and selected human metabolites under sewage conditions utilizing a combination of liquid chromatography–tandem mass spectrometry and high‐resolution mass spectrometry (HRMS). Target analytes included SCRAs with indole (5F‐PB‐22, PB‐22 pentanoic acid), indazole (AMB‐FUBINACA, 5F‐ADB, 5F‐ADB dimethylbutanoic acid), carbazole (MDMB‐CHMCZCA, EG‐018), and γ‐carboline (Cumyl‐PeGaClone) chemical core structures representing most of the basic core structures that have occurred up to now. Stability tests were performed using wastewater effluent containing 5% activated sludge as inoculum to monitor degradation processes and formation of transformation products (TPs). The majority of investigated SCRAs, excluding the selected human metabolites, was recalcitrant to microbial degradation in sewage systems over a period of 29 days. Their stability was rather controlled by physico‐chemical processes like sorption and hydrolysis. Considering a typical hydraulic in‐sewer retention time of 24 h, the concentration of AMB‐FUBINACA decreased by 90% thus representing the most unstable SCRA investigated in this study. Among the 10 newly identified TPs, three could be considered as relevant markers and should be included into future WBE studies to gain further insight into use and prevalence of SCRAs on the drug market.

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