P16: Hair analysis for synthetic cannabinoids: A study on the issue of passive contamination by side-stream smoke

Abstract

Introduction As hair analysis is often used for abstinence control it is crucial to consider contamination by passive exposure, particularly when drugs are smoked. In this study, the composition of main-stream and side-stream smoke of herbal mixtures containing synthetic cannabinoids was investigated and put into the context of head hair concentrations of samples collected from individuals repeatedly exposed to side-stream smoke. Methods To study the smoke composition a cigarette containing the synthetic cannabinoids JWH-018, JWH-122 and JWH-210 was smoked in a burning chamber by pulls of a piston syringe (puffvolume 35 mL/3 s, intervals 30 s). A constant air-flow of 1 L/min was applied to collect the side-stream smoke. The ethanolic solutions of main-stream and side-stream smoke condensates collected in gas wash bottles were analyzed by GC-MS. Hair contamination was studied with three volunteers who exposed their hair to the side-stream smoke of a synthetic cannabinoid cigarette five days a week during three consecutive weeks. Hair samples were obtained on a weekly basis during the exposure period and the following three weeks. Hair samples and wash solutions (water, acetone and petrol ether) were analyzed for synthetic cannabinoids by LC-MS/MS. Results Similar amounts of the synthetic cannabinoids were found in main-stream and in side-stream smoke condensates. The concentrations in hair increased with time during the exposure period (maximum concentrations were measured after the third week of exposure in a distal hair segment: 71 pg/mg JWH-018, 260 pg/mg JWH-122 and 600 pg/mg JWH-210). The concentrations decreased after the end of exposure, but most segments were still positive three weeks after the end of exposure. Regarding the washing solutions, only the acetone washings were tested positive and the analyte amounts were equal or less when compared with the amounts detected in the hair extracts. The concentration ratios of synthetic cannabinoids in hair were in good agreement with the concentration ratios in the mixture used for the exposure experiment with side-stream smoke. Conclusion Amounts of synthetic cannabinoids reaching the sidestream smoke are about as high as the amounts inhaled during smoking. Thus, hair contamination by side-stream smoke is very likely to occur and was confirmed by our smoke exposure study. The concentrations in hair after exposure are in the middle to high range compared to typical concentrations in forensic samples. Therefore, when utilizing hair analysis for abstinence control, candidates should be provided with information on the risks of external contamination. In forensic cases, utmost care has to be taken to prevent wrong conclusions when interpreting positive findings of synthetic cannabinoid in hair.