[Simultaneous determination of 102 synthetic cannabinoids in electronic cigarette oil by liquid chromatography-tandem mass spectrometry].

ABSTRACT

Synthetic cannabinoids (SCs), which are among the most widely abused new psychoactive substances, are much more potent and have greater efficacy than natural cannabis. SCs can be disguised in various ways and are commonly sold in the form of electronic cigarette oil. SCs belong to a large family with structures consisting of a core with substituents, linker, ring with substituents, and tail. New SCs can be developed by adding substituents, such as halogen, alkyl, and alkoxy groups, to the aromatic ring system or by changing the alkyl chain length. Since the emergence of so-called first-generation SCs, subsequent developments have led to eighth-generation indole/indazole amide-based SCs. As of July 1, 2021, the entire category of SCs was added to the list of controlled substances, but implementation requires urgent improvements in detection technologies. Typically, each method is limited to a few SCs. Owing to the vast number of chemically diverse SCs and their fast update speed, the determination and identification of various types of SCs using a single method is challenging. Therefore, rapid, sensitive, and accurate quantitative methods that includes various types of SCs must be developed to meet the demand for the qualitative and quantitative analysis of new SCs in seized electronic cigarette oil. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of 102 SCs in electronic cigarette oil. The mass spectrometry and liquid-phase conditions influencing SC separation and determination were optimized. Using the external standard method, 102 SCs were successfully identified in electronic cigarette oil. The samples were extracted using methanol. Target analytes were separated on a Shimadzu Shim-pack GIST-HP C18 AQ column (100 mm×2.1 mm, 1.9 µm) at a column temperature of 40 ℃. The mobile phases consisted of (A) 0.1% formic acid aqueous solution and (B) methanol-acetonitrile (1∶1, v/v). The gradient elution conditions were as follows 0-8 min, 55%A-15%A; 8-15 min, 15%A; 15-16 min, 15%A-55%A; 16-18 min, 55%A. The flow rate was 0.4 mL/min and the injection volume was 1 µL. Operating in the multiple reaction monitoring mode, the 102 SCs were identified within 18 min. Each SC exhibited a good linear relationship in the range of 1-100.0 µg/L with a correlation coefficient (r)≥0.9915. The limits of detection were 0.01-0.30 µg/L and the limits of quantification were 0.04-0.99 µg/L, which meet the requirements for analyzing SCs in actual samples. Precision was determined using standard solutions with 2, 10, and 50 µg/L of the SCs. The precisions (n=6) were 0.3%-6.0%. The recoveries of the 102 SCs, as evaluated by spiking electronic cigarette oil at low (2 µg/mL), medium (10 µg/mL), and high (50 µg/mL) levels, were 80.1%-119.8%. Good performance was observed for the analysis of real samples. The developed method is accurate, rapid, sensitive, and effective for the determination of the 102 SCs in electronic cigarette oil, satisfying the requirements for practical qualitative and quantitative analysis.