Contactless decontamination of hair samples: cannabinoids

Abstract

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 -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.

Reply to Restolho et al. ‘Contactless decontamination of hair samples: cannabinoids’

“…First of all, we would like to thank Drs Moosmann and Auwärter for their interest in our paper, which describes a new approach for hair decontamination prior to cannabinoids analysis. [1] Although we feel that scientific discussion regarding published work is valuable, there were some misunderstandings and incorrect assumptions concerning their interpretation [2] of our work, which we aim to clarify in this letter.…”

“…We would like to reply to a paper recently published by Restolho et al in Drug Testing and Analysis with the title 'Contactless decontamination of hair samples: cannabinoids'. [1] Although the authors present an interesting approach for trying to remove Δ9-tetrahydrocannabinol (THC) and Δ9-tetrahydrocannabinolic acid A (THCA-A) originating from external contamination by applying ionic liquids, we see ourselves obliged to respond to several imprecise and incorrect statements in the paper. In addition, from our point of view, there are some serious weaknesses in the experimental set-up of the decontamination study to be addressed.…”

Response to the letter to the editor Reply to Restolho et al. “Contactless decontamination of hair samples: cannabinoids” by Moosmann and Auwärter

“…The authors disagree with our contamination method and the 'unrealistic' THC concentrations obtained. We understand their point, and that is why we commented on this issue in our paper using the exact same words, in the Results and Discussion section [1] :…”

“…First of all, we would like to thank Drs Moosmann and Auwärter for their interest in our paper, which describes a new approach for hair decontamination prior to cannabinoids analysis. [1] Although we feel that scientific discussion regarding published work is valuable, there were some misunderstandings and incorrect assumptions concerning their interpretation [2] of our work, which we aim to clarify in this letter.…”

“…In Moosmann and Auwärter's letter, the need of more effective decontamination process is questioned, though we do not share their opinion. As we state in the introduction of our paper [1] : 'to detect THCCOOH more sensitive techniques are needed (e.g. gas chromatography-tandem mass spectrometry (GC-MS/MS), which are quite expensive and not available in most laboratories.…”