Determination of Chlormequat in Muscles of Mice by Solid Phase Extraction-Liquid Chromatography-Tandem Mass Spectrometry
A method for the determination of chlormequat(CQ) in muscles of mice using solid phase extraction with liquid chromatography tandem mass spectrometry was developed.CQ was extracted using acetonitrile,cleaned-up by Weak Cation-exchange(WCX) solid phase extraction(SPE) cartridges and then eluted by 3 mL of formic acid-methanol(1 ∶ 99,V/V) by gravity.The separation was performed on a hydrophilic interaction liquid chromatography(HILIC) column with aqueous solution containing 10 mmol/L ammonium acetate and 0.1% formic acid-acetonitrile(40 ∶ 60,V/V) as the mobile phase.CQ was determined in the mode of electrospray ionization source(ESI+) and multiple-reaction monitoring(MRM).The quantification was carried out by matrix-matched external standard curve.The results showed that the calibration curve was linear in the range of 5.0-500.0 μg/L with the correlation coefficient of 0.9991.The mean recovery of CQ in spiked muscle samples was 73.2%-82.3% and the relative standard deviation(RSD) was less than 9.3% at 10.0,100.0 and 200.0 μg/kg with three spiked levels(n=7).The limit of quantification(LOQ) for CQ was 10.0 μg/kg.The method was successfully applied to the analysis of trace level of CQ in muscles of mice.