免疫亲和柱净化-超高效液相色谱-串联质谱检测鱼虾中3-甲基-喹噁啉-2-羧酸

将特异性强的免疫亲和柱应用到3-甲基-喹噁啉-2-羧酸(methyl-3-quinoxaline-2-carboxylic acid,MQCA)的净化中,建立鱼虾中MQCA的免疫亲和柱净化-超高效液相色谱-串联质谱的快速分析方法。匀质好的样品经2 mol/L盐酸溶液酸解后,将提取液pH值调节至7~8,经过免疫亲和柱富集和净化后,采用超高效液相色谱-串联质谱测定,外标法定量。以甲醇-0.1%甲酸溶液为流动相,梯度洗脱分离,电喷雾正离子多反应监测模式监测。结果显示,水产品中MQCA在1.0~50.0 ng/mL范围内呈良好线性,线性相关系数大于0.995,定量限为1.0μg/kg。MQCA在1.0、5.0μg/kg和20.0μg/kg3种添加水平条件下的加标回收率为74.2%~86.5%,相对标准偏差小于10%。结果表明本方法重复性好、灵敏度高,适合水产品中MQCA的实际测定。

Determination of Methyl-3-quinoxaline-2-carboxylic Acid in Fish and Shrimp Samples by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry with Immunoaffinity Column Cleanup

A new approach for the determination of methyl-3-quinoxaline-2-carboxylic acid (MQCA) residue in fish and shrimp samples by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) based on immunoaffinity column (IAC) purification was developed. MQCA was extracted from samples with 2 mol/L hydrochloric acid and adjusted with water to pH 7–8. After being cleaned up and concentrated by immunoaffinity column, the analyte was analyzed by UPLC-MS/MS with electrospray ionization in positive ion mode (ESI+) using multiple reaction monitoring (MRM) and quantitatively determined by an external standard method. The separation was performed on an ACQUITY UPLC BEH C18 column with a gradient system consisting of 0.1% formic acid (V/V) and methanol as the mobile phase. Good linearity in response was obtained in the concentration range of 1.0–50.0 ng/mL with correlation coefficients larger than 0.995. The limit of quantification (LOQ) was 1.0 μg/kg. The average recoveries of MQCA at spiked concentrations of 1.0, 5.0, and 20.0 μg/kg ranged from 74.2% to 86.5% with relative standard deviations (n = 5) less than 10%. The method is simple, fast, sensitive and reliable, and suitable for the determination of MQCA residue in fish and shrimp samples.