An analytical method based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for detecting chlorate and perchlorate residues in milk power. Chlorate and perchlorate in milk power were extracted using a 0.1% (v/v) formic acid-acetonitrile solution. The extract was centrifuged at 10000 r/min for 10 min, and the supernatant was cleaned up on a PRiME HLB column. Separation of chlorate and perchlorate was performed on an ion-exchange column (Thermo Scientific Acclaim TRINITY P1, 50 mm×2.1 mm, 3 μm) by gradient elution using acetonitrile and 20 mmol/L ammonium acetate solution as the mobile phase. The analytes were identified by MS/MS. Quantification was achieved using internal standards. Chlorate and perchlorate demonstrated good linearity in the ranges of 2.0-40.0 and 1.0-20.0 μg/L, respectively, with correlation coefficients (r2) greater than 0.999. The limits of quantification (LOQs) of chlorate and perchlorate were found to be 15.0 and 7.5 μg/kg, respectively. The recoveries of chlorate and perchlorate ranged from 89.24% to 107.85% at the three spike levels of 30.0, 60.0, and 120.0, and 15.0, 30.0, and 60.0 μg/kg, respectively, with relative standard deviations (RSDs) ranging from 3.15% to 10.42% (n=6). This method is convenient, rapid, accurate, and efficient, thus demonstrating its suitability for use in the determination of chlorate and perchlorate in milk power.
Keywords: chlorate; high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS); milk power; perchlorate.