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Synthetic cannabinoids (SCs) are a series of structurally related analogs continually created to evade surveillance and sanction, which pose more severe hazards compared with traditional marijuana. Currently, synthetic cannabinoids have become the most diverse and widely abused classes of new psychoactive substances (NPS). Considering the serious threat posed by these substances, our country has regulated all categories of synthetic cannabinoids since July 1, 2021, which means that the establishment of rapid screening strategies of synthetic cannabinoids shall be further promoted. Here, a method of ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of 112 synthetic cannabinoids in hair. The hair samples were firstly extracted with methanol, and the supernatant was taken for injection. Then 0.1% formic acid aqueous solution and 0.1% formic acid acetonitrile solution were used as mobile phase, and the ACQUITY UPLC BEH C18 chromatographic column was used for separation. The samples were analyzed under the scheduled MRM mode through two or three ion channels specially selected for each compound with optimized collision energy. A major challenge in this experiment is the differentiation of isomers or synthetic cannabinoids with a similar mass number especially for the mass spectrometry, so the optimization of chromatographic conditions was thoroughly investigated, and a general chromatographic method for the 112 synthetic cannabinoids and two complementary methods for isomers were finally determined. The methodological validation results showed that the detection limits of 112 synthetic cannabinoids ranged from 0.5 to 5 ng/g, the linear correlation coefficient (r) was better than 0.999 0, and the matrix effect and extraction recovery were 81.0%-117.8% and 80.4%-119.7% with different concentration levels (1, 5, 25, 100 ng/g), respectively. Finally, fifteen hair samples in actual cases were detected by this method and the results showed that five kinds of synthetic cannabinoids were identified and quantified with the contents range of 1.4-48.2 ng/g. Furthermore, the results also exhibited minimal background interference in chromatograms of actual samples, indicating that this established strategy has high quantitative accuracy and can be widely used in the qualitative and quantitative analysis of practical cases. In addition, the method has high efficiency in high-throughput screening, which can simultaneously identify all kinds of synthetic cannabinoids reported in China so far. [ABSTRACT FROM AUTHOR]

Dapagliflozin is a sodium-glucose co-transporter-2 (SGLT2) inhibitor for treating type Ⅱ diabetes. In the process of synthesizing dapagliflozin, 5-bromo-2-chloropheny-4'-ethoxyldiphenylmethanone (compound 1) is a key intermediate. According to the literatures, there is always by-product 5-bromo-2-chloropheny-2'-ethoxyldiphenylmethanone (compound 2) in the synthesis procedure of compound 1. Due to the similarities of the two isomers in physical and chemical properties, it's difficult to separate and differentiate compound 1 and 2. As compound 2 affects the purity of dapagliflozin, it is of great importance to establish a method to rapidly distinguish compound 1 from compound 2. In this article, high performance liquid chromatography-ion trap-time of flight mass spectrometry (HPLC-IT-TOF MS) method was used to analyze compound 1 and 2. The samples were dissolved in methanol for direct injection. Under the optimized chromatographic conditions, good separation for the two isomers was obtained on a Capcell PAK C18 column (250 mm×4.6 mm×5 μm) with a mobile phase of water （0.1% formic acid） and acetonitrile-methanol (3∶1, V/V) at a flow rate of 0.6 mL/min. The target compounds were assayed by IT-TOF MS/MS in positive mode with the spray voltage set at 1.77 kV. The nitrogen flow was set at 1.5 L/min, and the capillary temperature was set at 200 ℃. The collision gas was helium. The ion at m/z 338.97 was chosen as the target to perform MS/MS experiment, and the collision energies were set at 10%, 15%, 20% and 25%, respectively. The MS/MS results under different collision energies were gained simultaneously by setting events in parallel on IT-TOF mass spectrometer. In order to visually distinguish the two isomers, breakdown curves were mapped by ［M+H］+ and fragment ions. The breakdown curves of the two isomers show significant differences, which provided strong support in this study. In addition, the element compositions of the three product ions were also confirmed by IT-TOF MS. Loss of C2H2 from the precursor ions of ［M+H］+ was observed in the MS/MS spectra of both the isomers. For compound 1, the major fragmentation pathway was loss of C2H5OC6H5 from ［M+H］+via a 2-step proton transfer. While, for compound 2,［M+H-C2H4O］+ via 1-4 H shift from ortho-substituted ethoxy group to the benzene ring was found to be the major product ion. The difference in the fragmentation pathways of the two isomers may be due to the different substitution sites of the ethoxy groups. When the ethoxy group is ortho-substituted, the 2-step proton transfer is quite difficult. As a result, it goes through loss of C2H4O mainly. The method is simple, effective and accurate, which is suitable for rapidly qualitative and semi-quantitative analysis of the isomers, and also can provide a reliable and effective technique for the quality control of dapagliflozin. [ABSTRACT FROM AUTHOR]