高效液相色谱串联质谱法测定食糖中4-甲基咪唑和2-甲基咪唑

Determination of 4-Methylimidazole and 2-Methylimidazole in Sugar by HPLC-MS/MS

建立了食糖中4-甲基咪唑和2-甲基咪唑的高效液相色谱串联质谱检测方法。食糖样品经乙醇充分提取,经PCX柱富集净化,氮吹干洗脱液,用乙腈-水(V/V=9/1)复溶,供高效液相色谱串联质谱仪检测。以乙腈和5 mmol/L乙酸铵水溶液(含0.1%甲酸)为流动相梯度洗脱,用ACQUITY UPLC BEN HILIC柱(1.7μm,100 mm×2.1 mm)分离,电喷雾正离子模式(ESI+)扫描,多反应监测模式(MRM)采集数据,外标法定量。结果显示,该方法在0.5~20.0μg/L浓度范围内线性关系良好,4-甲基咪唑和2-甲基咪唑的相关系数分别为0.9999和0.9994,检出限分别为0.07和1.07μg/kg,定量限分别为0.24和3.57μg/kg。在5.0、10.0、15.0μg/kg的加标水平下,4-甲基咪唑和2-甲基咪唑的平均回收率在81.2%~96.9%之间,相对标准偏差在1.4%~5.1%(n=6)之间。本方法操作简单,结果准确可靠、灵敏度高,适用于食糖中4-甲基咪唑和2-甲基咪唑的残留量测定。

A method for the detection of 4-Methylimidazole and 2-Methylimidazole in sugar by high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS)was established.The sugar sample was fully dissolved and extracted with ethanol,enriched and purified by the PCX column.The eluent was concentrated by nitrogen,and then reconstituted with acetonitrile-water solution(V/V=9/1).Chromatographic separation was performed on a ACQUITY UPLC BEH HILIC column(1.7μm,100 mm×2.1 mm)with acetonitrile and 5 mmol/L ammonium acetate solution(containing 0.1%formic acid)as mobile phase,gradient elution was employed,4-Methylimidazole and 2-Methylimidazole were monitored in the multiple reaction monitoring(MRM)mode with positive electrospray ionization(ESI+)and quantified by the external standard method.In this method,good linearity was obtained in the range of 0.5~20.0μg/L(r2≥0.9994),The limits of detection(LOD)were 0.07,1.07μg/kg and the limits of quantification(LOQ)were 0.24,3.57μg/kg.The average recoveries of 4-Methylimidazole and 2-Methylimidazole at three levels of 5.0,10.0 and 15.0μg/kg were from 81.2%to 96.9%with the RSDs of 1.4%~5.1%(n=6).This method is simple and the result of this method is accurate and reliable,highly sensitive,and is suitable for the determination of 4-Methylimidazole and 2-Methylimidazole furfural in sugar.