Determination of chlormequat chloride residues in animal derived foods by high performance liquid chromatography-tandem mass spectrometry

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 mmx2. 1 mm, 3 mu m) 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 mu g / L for CCC, with correlation coefficients (r(2)) no less than 0. 999 3. The limit of quantification (LOQ) of the method was 0. 500 mu g / 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. 500500 mu g / 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.