Abstract: 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.

Key words: high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), sodium picosulfate, enzyme product, illegally added, slimming