高效液相色谱-串联质谱法检测牛组织和奶中咪多卡残留的研究

建立了一种检测牛组织和牛奶中咪多卡残留检测的高效液相色谱-串联质谱法。牛组织(肌肉、肝脏、肾脏、脂肪)和奶在NaAc缓冲体系中酶解,经HCl溶液提取,WCX固相萃取柱净化,以0.3 %甲酸水溶液(含20mM甲酸铵)和0.3 %甲酸乙腈为流动相进行梯度洗脱,在HILIC色谱柱上分离,在电喷雾正离子(ESI+⁾模式下,用多反应监测(MRM)模式检测,同位素内标法定量。结果表明：咪多卡在2.5～1000 ng/mL的浓度范围内呈现良好线性关系,相关系数(R2⁾大于0.99；咪多卡在牛组织和奶中的检测限均为10 μg/kg,定量限均为20 μg/kg；咪多卡在牛组织和奶中20～4000 μg/kg添加浓度水平上的回收率在70.9～109%范围内；批内RSD在0.55~9.59%之间,批间RSD在2.21~12.1%之间。该方法具有灵敏度高、定量准确,重复性好等特点,可以满足牛组织和奶中咪多卡残留检测的要求。

Detection of Imidocarb Residues in Cattle Tissues and Milk by High Performance Liquid Chromatography-Tandem Mass Spectrometry

A high performance liquid chromatography-tandem mass spectrometry method was established for the determination of imidocarb residues in cattle tissues (muscle, liver, kidney, fat) and milk. Imidocarb was enzymolized in sodium acetate buffer, and extracted with HCl solution. Then the sample solutions were purified with WCX SPE column. The mobile phase were formic acid solution (20 mM ammonium formate) and acetonitrile (0.3% formic acid), and the samples were separated by HILIC column. The residues was analyzed by positive ion electrospray ionization (ESI+^{) applying the detection mode of MRM} and quantified by isotopic internal standard. Good linearities of the calibration curves were obtained with the range of 2.5~1000 ng/mL, the correlation coefficient R2^＞0.99. The limit of detection of imidocarb was 10 μg/kg, and the limit of quantification of imidocarb was 20 μg/kg. The recoveries of imidocarb residues were 70.9~109%, for cattle tissues (muscle, liver, kidney, fat) and milk at the concentrations of 20~4000 μg/kg. The intra- batch variation coefficients were 0.55~9.59%, and inter-batch variation coefficients were 2.21~12.1%. With high sensitivity, good accuracy and repeatability, the method can be applied for the determination of imidocarb residues in cattle tissues and milk.