Purpose: The aim of this study is to investigate the stabilities of the 24 synthetic cannabinoid metabolites (SCMs) in blood and urine at various temperatures from - 30 to 37 ℃ stored for 1-168 days. In addition, experiments of stabilities at lower temperatures and for much longer duration have been performed as described below.
Methods: The quantification was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The blank blood and urine spiked with SCMs and non-spiked real case (authentic) specimens were incubated at 37 ℃ up to 56 days and at 22, 4 or - 30 ℃ up to 168 days. The non-spiked authentic blood and urine specimens were also stored at - 30 or - 80 ℃ for 1, 3 or 5 years to investigate stabilities during very long time frames.
Results: All the 24 SCMs were much more stable in urine than in blood at 37, 22 or 4 ℃. All 24 SCMs spiked into blood or urine were stable at - 30 ℃ for up to 168 days. The 6 SCMs in the authentic specimens exhibited long stabilities at - 30 or - 80 ℃ for 3-5 years. Some tendencies were observed according to the relation between the structures of SCMs and their stabilities.
Conclusions: The long-term stabilities of 24 SCMs in spiked samples and those of 6 SCMs in the authentic specimens were examined using LC-MS/MS. SCMs were largely very stable and usable several years after storage at - 30 or - 80 ℃.
Keywords: Blood and urine; Deep-freezing; Human authentic specimens; LC–MS/MS; Long-term stability; Synthetic cannabinoid metabolite.
© 2022. The Author(s), under exclusive licence to Japanese Association of Forensic Toxicology.