目的采用液相色谱-串联质谱(LCMS/MS)建立水产品中孔雀石绿及其隐色代谢物残留的检测方法。方法均质后的水产品样品,用乙腈和乙酸铵缓冲液提取,合并提取液,用二氯甲烷反提取,经中性氧化铝柱和丙磺酸(PRS)柱固相萃取净化,没有使用氧化铅柱在线氧化,色谱分离后直接进入串联质谱检测器。采用电喷雾(ESI)正离子扫描模式,多反应监控(MRM)方式检测,外标法定量。结果孔雀石绿和隐色孔雀石绿的检出限为0.5ng/g,线性方程的相关系数r〉0.99,在添加浓度0.5~2.0ng/g范围内,孔雀石绿回收率为78.4%~92.1%。隐色孔雀石绿回收率为82.4%~98.1%,相对标准偏差(RSD)均小于5.7%。结论此方法高效快速,结果准确,重现性好,适合于对水产品中孔雀石绿和隐色孔雀石绿的残留检测。
Objective To develop a method for determination of residues of malachite green (MG) and its leucometabolite leucomalachite green (LMG) in aquatic products by liquid chromatography tandem mass spectrometry (LC-MS/MS). Methods The targeted analytes were extracted from homogenized samples with a mixture of acetonitrile and ammonium acetate buffer, partitioned against methylene chloride, and purified on tandem neutral alumina and PRS SPE cartridges. Chromatographic separation was achieved by using ZORBAX SB-C18 column with an isocratic mobile phase consisting of ammonium acetate (0.05 mmol/L) and acetonitrile (10/90, V/V) without the need for in-line post-column oxidation with PbO2. Identification and quantification were performed using multiple reaction monitoring (MRM) with one precursor ion and two product ions for each analyre and electrospray ionization (ESI) in positive mode. Results The limit of detection for MG and LMG was 0.5 ng/g, correlation coefficient of linear regression equations was above 0.99 and the recoveries were in the range of 78.4%-92.1%,0. 82.4%-98.1% respectively, at spiked levels of 0.5--2.0 ng/g. The RSD of the method was less than 5.7%. Conclusion After a large amount of incurred samples were detected, the results showed that the method is suitable for determination of residues of MG and LMG in aquatic products.