[Simultaneous determination of 17 preservatives and antioxidants in condiments using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry]

An ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) method was developed for the simultaneous determination of 11 preservatives and 6 antioxidants in condiments. The condiment sample with low fat or middle fat was diluted with saturated NaCl solution (adjusting pH to 2 - 3 with phosphoric acid), then extracted with acetonitrile. The extract was purified using liquid-liquid extraction with hexane, and the sample with middle fat was further purified using solid phase extraction with a C8 column. The condiment sample with high fat was diluted with hexane, then dissolved with saturated NaCl solution (adjusting pH to 2 -3 with phosphoric acid), and extracted with acetonitrile. The extract was purified using solid phase extraction with a C8 column. The analysis was performed on a C18 column (150 mm x 2.1 mm, 1.7 microm) using a gradient elution with the mobile phases of 20 mmol/L ammonium acetate buffer and acetonitrile, and determined by tandem mass spectrometry in negtive ESI mode under multiple reaction monitoring (MRM) mode. The method had good linearity (r > or = 0.995 5). The limits of quantification (LOQs) (S/N = 10) of 17 analytes ranged from 0.05 mg/kg to 5 mg/kg. The recoveries ranged from 79.7% to 118% at three spiked levels, the relative standard deviations (RSDs) ranged from 0.57% to 13.1%. The method can be applied for the determination of preservatives and antioxidants in condiments.