酶抑制法快速检测牛奶中β-内酰胺酶抑制剂多残留

建立一种酶抑制法用于牛奶中β-内酰胺酶抑制剂的多残留检测。采用乙腈沉淀蛋白、正己烷除脂，基质匹配外标法定量，有效消除牛奶基质的干扰。方法对4 种常见的β-内酰胺酶抑制剂在牛奶中的检出限分别为舒巴坦42.88 μg/kg，克拉维酸钾10.20 μg/kg，他唑巴坦1.68 μg/kg，阿维巴坦钠3.48 μg/kg；添加回收率在80.43%～115.87%之间；变异系数不超过10.14%。牛奶中β-内酰胺酶残留量不超过40 U/mL时，不影响检测结果的准确性。方法与液相色谱-串联质谱法的检测结果相关系数R2为0.982，一致性良好。该酶抑制法具有准确、快速、可高通量及多残留检测的特点，尤其适用于对大量牛奶样本中β-内酰胺酶抑制剂多残留的现场筛查。

An Enzyme Inhibition Method for Rapid Multi-residue Determination of β-Lactamase Inhibitors in Milk

An enzyme inhibition method was established and used for multi-residue detection of β-lactamase inhibitors in milk. For sample preparation, the protein was precipitated with acetonitrile and the fat was removed with n-hexane. The matrix-matched external standard method was used for quantification, which eliminated the interference of the milk matrix. The detection limits of sulbactam, potassium clavulanate, tazobactam and avibactam sodium in milk samples were 42.88, 10.20, 1.68 and 3.48 μg/kg, respectively. The average spiked recoveries were from 80.43% to 115.87% with variation coefficients below 10.14%. When the residue of β-lactamase in milk did not exceed 40 U/mL, the assay results obtained using the developed method were accurate. Good agreement between the results of this method and those of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was obtained for spiked milk samples, with a correlation coefficient (R2) of 0.982. The enzyme inhibition method allowed accurate, rapid, high-throughput and multi-residual detection of β-lactamase inhibitors, and was particularly suitable for on-site screening for β-lactamase inhibitor residues in large numbers of milk samples.