A method for the determination of chlormequat chloride (CCC) residues in animal derived foods by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The samples were extracted with acetonitrile containing 1% (v/v) acetic acid and defatted with n-hexane, followed by clean-up on a cationic solid phase extraction column. The analytes were separated on a Venusil MP C18(2) column (150 mm×2.1 mm, 3 μm) under a gradient elution program using acetonitrile and 0.1% (v/v) formic acid aqueous solution as the mobile phases. Then, the analytes were detected by tandem mass spectrometry using a positive electrospray ionization (ESI+) source in the multiple reaction monitoring (MRM) mode. Matrix-matched internal standard calibration curves were used for quantitative analysis. The calibration curves showed good linearity in the range of 0.200-500 μg/L for CCC, with correlation coefficients (r2) no less than 0.9993. The limit of quantification (LOQ) of the method was 0.500 μg/kg. The average recoveries of CCC in pork, beef, mutton, chicken, egg, pig kidney, beef liver, sheep kidney, chicken liver and milk matrices at spiked levels of 0.500-500 μg/kg were 93.4%-101%, and the relative standard deviations were 2.3%-8.0%. The method has less matrix interference, with high sensitivity, accuracy and reliability, and it is suitable for the quantitative detection of CCC residues in animal derived foods.
Keywords: animal derived foods; chlormequat chloride (CCC); high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS); solid phase extraction (SPE).