Is the mere absence of dimethyltryptamine in hair evidence of ayahuasca non-exposure? Development of an LC-MS/MS method for the comprehensive quantification of β-carbolines and tryptamines in hair

Aim

Ayahuasca is a hallucinogenic drink consumed during shamanic rituals for spiritual and curative purposes. In recent years, the use of this beverage was no longer restricted to the Amazon rainforest but has spread all over the world and notably in Europe. The internationalisation of Ayahuasca raises risks associated with its consumption during rituals performed by individuals lacking in knowledge of the psychotropic ingredients and who could abuse the situation of an emotional and a physical vulnerability. To document exposure to ayahuasca, hair analysis could be very helpful, with application in both clinical and historical contexts to evidence the consumption of this substance. This can also be done on archaeological specimens.

Method

In this study, the hair of a subject suspected of ayahuasca consumption were analysed using an original LC-MS/MS method. Unfortunately, as a private expertise, there is no information about the case history. The head hair sample (dark brown in colour, 3.5 cm in length) was decontaminated twice with 5 mL dichloromethane for 2 minutes and dried. The hair strand was cut in 0–1, 1–2 and 2–3.5 cm and 20 mg of each segment, cut into very small fragments, were incubated in 1 mL buffer borate pH 9.5 for 16 h at 40° C, in the presence of 1 ng of MDMA-D5 used as IS. Then, 5 mL of a mixture of ether/dichloromethane/hexane/isoamyl alcohol (50: 30: 20: 0.5) was added. After agitation for 15 min and centrifugation (15 min, 3000 rpm), the organic phase was collected and evaporated to dryness under a nitrogen flow on a plate heated at 50° C. The residue was reconstituted in 30 μL of 5 mM ammonium formate buffer adjusted to pH 3.

Results

For the analysis of β-carbolines and tryptamines, a method was developed and validated with LOD and LOQ at 0.1 and 1 pg/mg respectively for all the analytes. The three β-carbolines harmine (2.5–1300 pg/mg), harmaline (30–89,700 pg/mg) and tetrahydroharmine (2.2–2.5 pg/mg) and the tryptamines 5-OH-DMT (2-62 pg/mg) and 5-MeO-DMT (< LOQ) tested positive. Dimethyltryptamine tested negative.

Conclusion

For the first time, values of all β-carbolines and 5-OH-DMT in hair are displayed in the literature. The absence of dimethyltryptamine in the hair proves that the analytical strategy to be used to evidence ayahuasca consumers should not be directed at the single research of DMT. Since there is not a single ayahuasca recipe, it will be necessary to test not only DMT but also the other ayahuasca alkaloids such as β-carbolines (harmine, harmaline and THH) and other tryptamines (5-OH-DMT and 5- MeO-DMT) to fully document exposure.