Quantification of (9R)- and (9S)-hexahydrocannabinol (HHC) via GC-MS in serum/plasma samples from drivers suspected of cannabis consumption and immunological detection of HHC and related substances in serum, urine, and saliva.

The semisynthetic cannabinoid hexahydrocannabinol (HHC) is currently getting a lot of media attention because the legal status in many countries is not clearly specified. In this study, a GC-MS method for the quantification of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) was extended to (9R)- and (9S)-HHC. The applicability was proven by serum/plasma samples from drivers suspected of cannabis consumption. Limit of detection (LOD) and lower limit of quantification (LLOQ) were 0.15 and 0.25 ng/mL, respectively. Within-run imprecision was <6.5% and between-run imprecision was <10.0%. Inter-injection stability, processed sample stability (3 days), freeze-thaw stability (three cycles), and storage stability (1 week room temperature; 1 month 4°C, -20°C) could be proven. Both HHC diastereomers could be detected in 17 (5.3%) out of 321 analyzed samples from traffic controls in Western Saxony. The mean ratio between (9R)- and (9S)-HHC was 1.99 (CV = 14.6%). Quantification resulted in concentrations between <LLOQ and 35.35 ng/mL for (9R)-HHC and <LLOQ and 21.76 ng/mL for (9S)-HHC. Additionally, cross-reactivities of HHC, 11-hydroxy-hexahydrocannabinol (11-OH-HHC), 11-nor-9-carboxy-hexahydrocannabinol (HHC-COOH), hexahydrocannabiphorol (HHC-P), hexahydrocannabinol acetate (HHC-O), and tetrahydrocannabidiol (H4-CBD) were evaluated in five immunological screening tests for serum, urine, and saliva. Urine test strips and ELISA tests for the detection in serum seem to be beneficial to detect HHC consumption in comparison with saliva tests. HHC analogs and H4-CBD showed no cross-reactivity with any of the tests.