L-半胱氨酸提取-高效液相色谱-电感耦合等离子体质谱法测定鱼肉中汞的三种形态

Determination of the three forms of mercury in fish by L-cysteine extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometry

目的建立L-半胱氨酸辅助提取-高效液相色谱-电感耦合等离子体质谱法测定鱼肉中无机汞、甲基汞和乙基汞3种汞形态。方法样品采用L-半胱氨酸提取,考察不同浓度L-半胱氨酸的提取效率,研究提取时间对提取效率的影响,优化流动相条件。结果在2%甲醇+0.04 mol/L乙酸铵+1 g/L L-半胱氨酸流动相条件下,用1%L-半胱氨酸超声辅助提取10 min,测定了鱼肉中汞的3种形态,均能在9 min内完成分离,3种汞形态线性相关系数均>0.999,无机汞、甲基汞、乙基汞的检出限分别为3.0、2.0和3.0μg/kg,加标回收率在92.2%~97.9%,精密度<2%,质控样测定值在定值区间内。结论该方法准确简单、方便快捷,适用于鱼肉中3种汞形态的测定,给相关检测机构提供参考。

Objective The aim of this study was to establish a method for determining inorganic,methyl,and ethyl mercury levels in fish using L-cysteine-assisted extraction-high-performance liquid chromatography-inductively coupled plasma mass spectrometry.Methods L-cysteine was used to extract mercury from the samples.The extraction efficiencies of different concentrations of L-cysteine were investigated.The effect of extraction time on extraction efficiency was also studied,and the mobile phase conditions were optimized.Results Using a mobile phase comprising 2% methanol+0.04 mol/L ammonium acetate+1 g/L L-cysteine,the three forms of mercury in fish were determined by ultrasonic-assisted extraction with 1%L-cysteine for 10 min.All samples were separated within 9 min.The linear correlation coefficients for the three forms of mercury were over 0.999.The limits of detection of inorganic mercury,methyl mercury,and ethyl mercury were 3.0,2.0,and 3.0μg/kg,respectively.The spiked recoveries were 92.2%-97.9%,and the precision was less than 2%.The measured values of the quality control samples were within the range of the fixed values.Conclusion The method developed herein is accurate,simple,convenient,and suitable for determining the three types of mercury in fish.