超高效液相色谱串联质谱法测定蚝油中3种甲基咪唑类物质

Determination of three methylimidazoles in oyster sauce using ultra-high performance liquid chromatography-tandem mass spectrometry

该文建立了超高效液相色谱串联质谱对蚝油中3种甲基咪唑类物质(N-甲基咪唑、2-甲基咪唑、4-甲基咪唑)的检测方法。样品用水提取,经混合型阳离子交换(MCX)固相萃取柱富集净化,采用超高效液相色谱-串联质谱进行测定,以HILIC色谱柱进行分离,电喷雾正离子,多反应监测模式检测,内标法定量。结果表明,3种甲基咪唑类物质在5~200 ng/mL呈良好的线性关系,线性相关系数均大于0.996,检出限均为5μg/kg,定量限均为10μg/kg。在3个加标水平下,3种甲基咪唑类物质的回收率在82.9%~113.1%,相对标准偏差小于10%。该方法操作快捷,稳定性好,可实现蚝油中3种甲基咪唑类物质的同时测定,在市售蚝油风险监测中应用。

The present study has established a laboratory method for the determination of three methylimidazoles(N-methylimidazole, 2-methylimidazole and 4-methylimidazole) in oyster sauce based on ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). The samples were extracted by water, enriched and purified with MCX solid-phase extraction column and assayed with UPLC-MS/MS. In addition, separated on HILIC column with electrospray ionization in a positive mode(ESI+), the samples were monitored with multiple reaction monitoring(MRM) and the target substances were quantified based on the internal standard method. The three methylimidazoles showed good linearity(R^2>0.996) within the range of 5-200 ng/mL, with the detection limit of 5 μg/kg and the quantification limit of 10 μg/kg for all the three substances. At three spiked levels, the recovery rate of all three methylimidazoles were within the range of 82.9%-113.1%,and the relative standard derivation was below 10%. This method features quick detection and high stability while enabling simultaneous determination of three methylimidazoles in oyster sauce, hence is suitable for application in risk monitoring of oyster sauces on the market.