Abstract:
In recent years, the misuse of synthetic cannabinoids has garnered significant societal attention. To evade regulation, synthetic cannabinoids are often illicitly mixed into e-cigarette liquids to create "heady e-cigarettes". The complex matrix of e-cigarette liquids poses a substantial challenge to the detection and regulation of synthetic cannabinoids, necessitating the development of methods suitable for rapid on-site detection of these substances in such products. A miniature ion trap mass spectrometer, with its high sensitivity, fast detection, and portability, is an ideal tool for detecting synthetic cannabinoids in e-cigarette liquids. In this study, a rapid detection method for synthetic cannabinoids in e-cigarette liquids was established based on acetone-assisted photoionization miniature ion trap mass spectrometry. The study revealed that the complex matrix present in e-cigarette liquids can mask the detection signals of synthetic cannabinoids, thereby significantly reducing detection sensitivity. Furthermore, matrix residues were found to cause severe contamination of the mass spectrometry instrument, resulting in an extended instrument recovery time of up to 360 min following contamination. To address this issue, a micro-heating desorption pre-separation module was proposed to achieve pre-separation of synthetic cannabinoids and e-cigarette liquid matrix components by exploiting the boiling point difference between them. Using 5F-EMB-PICA as a representative compound, the effects of temperature and heating time of the micro-heating desorption on the detection signal intensity were investigated. The optimal temperature was found to be 150 ℃, and the optimal heating time was 5 min. Under these conditions, the heating pre-separation strategy successfully minimized the interference from e-cigarette matrix components, achieving optimal detection sensitivity while reducing instrument contamination. The instrument recovery time was reduced to only 1 min. To demonstrate the universality of the method, three typical synthetic cannabinoids (e.g., 5F-EMB-PICA, 4F-ABUTINACA, and 4F-MMB-BUTINACA) in different flavors of e-cigarette liquids were investigated, all of which were accurately and rapidly detected. In addition, the method exhibits high sensitivity for detecting all three synthetic cannabinoids at concentrations as low as 5 mg/L. This detection limit is significantly lower than the typical synthetic cannabinoid concentration range (0.58%-2.71%) found in "heady e-cigarettes", thereby fully covering the potential content of illicit additives in e-cigarette products. This method not only offers excellent detection performance, but also features fast response, low cost and short instrument recovery time, making it suitable for on-site identification of illicitly added synthetic cannabinoids in e-cigarette liquids. With the continuous expansion of the e-cigarette market and the growing severity of related drug crimes, this method is expected to provide important support for the on-site detection of synthetic cannabinoids in e-cigarette liquids.