Contactless decontamination of hair samples: cannabinoids

Room temperature ionic liquids (ILs) have already been shown to provide efficient extraction media for several systems, and to capture volatile compounds, namely opiates. In this work, a novel, contactless, artefact‐free extraction procedure for the removal of Δ 9 ‐tetrahrydrocannabinol (THC) from the surface of human hair is presented. To prepare in vitro cannabinoids‐contaminated hair, samples were flushed with hashish smoke for 7 h. The decontamination experiments were carried at 100 °C for 24 h, according to the procedure previously described. Fifty‐three ILs were screened and presented decontamination efficiencies ranging from 0 to 96 %. Although the majority of the ILs presented efficiencies above 90%, the 1‐ethanol‐3‐methyl tetrafluoroborate (96%) was chosen for further process optimization. The Design of Experiments results demonstrated that all studied variables were significant for the process and the obtained optimum conditions were: 100 °C, 13 h and 175 mg of IL. In the work of Perrotin‐Brunel et al . ( J . Mol . Struct . 2011, 987 , 67), it is demonstrated that, at 100 °C, full conversion of tetrahydrocannabinolic acid (THCA) into THC is obtained after 60 min. Since our decontamination takes place over 13 h at 100 °C, full conversion of THCA into THC is expected. Additionally, our method was compared with the method proposed by Cairns et al . ( Forensic Sci . Int . 2004, 145 , 97 ), through the analysis of 15 in vitro contaminated hair samples. The results demonstrated that with our method a mean extraction efficiency of 11 % higher was obtained. Copyright © 2016 John Wiley & Sons, Ltd.