分散固相萃取净化/高效液相色谱-串联质谱法测定水产品中的5种硝基咪唑类药物残留

建立了水产品中5种硝基咪唑类药物的高效液相色谱-串联质谱检测方法。样品经含0.1%氨水乙腈提取,加无水硫酸钠、C18-N以及NH2-PSA净化剂后涡旋振荡对样品进行净化,以Merck Chromolith Performance RP-18e(4.6 mm×100 mm)色谱柱分离,甲醇和0.1%甲酸水溶液为流动相梯度洗脱,正离子模式电喷雾电离,配合多反应离子扫描(MRM)定性定量分析目标化合物。考察了提取剂中氨水和净化剂的用量对加标回收率的影响,在优化实验条件下,5种硝基咪唑类药物在20~500μg/L范围内线性关系良好,r2≥0.998 9;3个加标水平下的方法回收率为77.2%~94.8%;定量下限为0.7~2.0μg/kg。该方法快速、简单、准确,适用于水产品中5种硝基咪唑类药物残留的检测。

Determination of Five Nitromidazoles in Aquatic Products by High Performance Liquid Chromatography-Tandem Mass Spectrometry Combined with Dispersive Solid Phase Extraction

A high performance liquid chromatography-tandem mass spectrometric(HPLC-MS/MS) method was developed for the determination of five nitromidazoles in aquatic products.Samples were extracted with acetonitrile containing 0.1％ (by volume) ammonium hydroxide,and then purified with a mixture of anhydrous sodium sulfate,C18-N and NH2-PSA.The analysis was performed by an HPLC-MS/MS system with Merck Chromolith Performance RP-18e(4.6 mm × 100 mm) column.The mobile phase consisted of methanol and 0.1％ (by volume) formic acid solution by gradient elution,and multiple reaction monitoring(MRM) mode with positive electrospray ionization was used.The effects of the dosages of ammonium hydroxide in extractant and anhydrous sodium sulfate,C1s-N and NH2-PSA in cleaning-up agent were studied.Under the optimized analytical conditions,the calibration curves for five nitromidazoles were linear in the concentration range of 20-500 μg/L with their correlation coefficients(r2) not less than 0.998 9.The recoveries at three concentrations ranged from 77.2％ to 94.8％ with the LOQs of 0.7-2.0 μg/kg.The method is suitable for the determination of 5 nitromidazoles in aquatic products.