Abstract: A sensitive HPLC-MS/MS method with high selectivity was developed for the determination of cyanuric acid residues in dairy products. Cyanuric acid in samples was extracted into acetonitrile/water system. The extract was deproteinized by adding additional acetonitrile, followed by high-speed centrifugation, before HPLC-MS/MS analysis in the internal standard mode. Electrospray ionization was applied and operated in the negative ion mode. An excellent linear range of this method for the determination of cyanuric acid was 0.005－0.2μg/mL with a correlation coefficient of more than 0.999. The average recovery rates in dairy products spiked with standard material at concentration levels of 0.2, 0.5, 1.0 mg/kg and 2.0 mg/kg were in the range of 91.7% to 99.6% with relative standard deviations less than 10%. The limit of detection of this method was 0.2 mg/kg.

Key words: dairy products, cyanuric acid, high performance liquid chromotographay tandem mass spectrometry