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A method based on high-performance liquid chromatography-tandem mass spectrometry was developed for the determination of sodium picosulfate in enzyme products. Sodium picosulfate is a new slimming aid that is illegally added to food products. The existing analytical methods are not suitable for application to jellies and gel candies, thus triggering the need for developing a new method. The samples were extracted with water and passed through a polyamide cartridge. The extracts were separated on a Thermo Accucore RP-MS column (100 mm×2.1 mm, 2.6 μm) using acetonitrile-10 mmol/L ammonium acetate solution (15:85, v/v) as the mobile phase. The flow rate of the mobile phase was 0.3 mL/min, and the column temperature was 35 ℃. Detection was carried out in the multiple reaction monitoring (MRM) mode. Quantification analysis was performed by the external standard method. The results showed that sodium picosulfate had a good linear relationship in the range of 5-500 μg/L, and the correlation coefficient (r) was 0.9999. The limit of detection (LOD) was 0.05 mg/kg. The average recoveries of sodium picosulfate in different matrices were in the range of 89.2%-111.8%, with the relative standard deviations (RSDs) of 2.5%-10.4%. The method was applied to the analysis of 152 samples, and 58 positive samples were detected. The positive rate was 38.2%. The developed method is accurate and sensitive, and it is suitable for detecting sodium picosulfate in enzyme products.

A method for determining chloramphenicol (CAP) in both propolis and propolis-derived dietary supplements was developed by utilizing high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The flavones in the samples were removed with a lead acetate solution and ammonia, and the fat-soluble interferences, such as beewax and vegetable oils, were removed with n-hexane after the sample dissolved in ethanol. Tert-butyl methyl ether was used as the back-extraction solvent to reduce co-extracting compounds, such as polyethylene glycol 400 (PEG 400) and glycerol, which are common adjuvants of dietary supplements, and some polar interferences. CAP was detected by HPLC-MS/MS and quantified by the internal standard method. The calibration curve showed a good linearity in the range of 0.20-50.0 μg/L. The limits of detection and the limits of quantification were 0.03 and 0.1 μg/kg, respectively. The recoveries in four different matrices at three spiked levels were in the 86.0%-114.4% range with the relative standard deviations from 0.3% to 4.9%. With the advantages of excellent universality, ease of operation, high sensitivity, and strong anti-interference capability, the proposed method was suitable for the determination of CAP in both propolis and propolis-derived dietary supplements.