Abstract: A method for the rapid determination of biotoxin (bongkrekic acid) in the Liushenqu was established using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with methanol by ultrasonication, then the pH was adjusted to 8 using ammonia. After filtration, the extract was purified using an Oasis Max strong anion exchange resin column. The Waters HSS T3 column (100 mm×2.1 mm, 1.8 μm) was used for the UPLC-MS/MS analysis. The mobile phase was acetonitrile-10 mmol/L ammonium formate solution (containing 0.1% (v/v) formic acid). MS analysis was performed using an electrospray ionization (ESI) source in the negative and multiple reaction monitoring (MRM) modes. Under the optimum conditions, the linear range of bongkrekic acid was 0.5-100 μg/L (correlations coefficient (R²)>0.99). The recoveries of the bongkrekic acid were 80.6%-85.3%. The intra-day and inter-day relative standard deviations (RSDs) were in the range of 4.2%-6.8% and 8.2%-13.2%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were 0.4 μg/kg and 1.2 μg/kg, respectively. The results showed that bongkrekic acid residues were detected in Liushenqu, thereby confirming the supporting role of our method for the risk monitoring of biotoxins in health foods and Chinese herbal medicines. This method is simple, easy, sensitive, and suitable for the determination of the bongkrekic acid residues in Liushenqu.

Key words: biotoxin, bongkrekic acid, Liushenqu, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)