血中甲基汞和无机汞的高效液相色谱-串联电感耦合等离子体质谱测定法

Determination of methylmercury and inorganic mercury in blood with high performance liquid chromatography-tandem inductively coupled plasma mass spectrometry

目的建立高效液相色谱-串联电感耦合等离子体质谱法(HPLC-ICP-MS)同时测定血中甲基汞和无机汞的方法。方法血样先加甲醇沉淀蛋白,再以含有0.05%(体积分数)2-巯基乙醇、3 g/L L-半胱氨酸和0.1%(体积分数)盐酸的溶液室温超声提取,样品中的甲基汞和无机汞经络合提取后,以含有5%(体积分数)甲醇、0.06 mol/L乙酸铵、0.05%(体积分数)2-巯基乙醇、3 g/L L-半胱氨酸的水溶液作为流动相,经C18液相色谱柱分离后,用ICP-MS No gas模式进行测定,外标法定量。结果甲基汞和无机汞分别在0.30~50μg/L和0.50~50μg/L的线性范围内,所得回归方程均呈较好的线性关系,r>0.999。该方法对样品中甲基汞、无机汞的检出限分别为1、1.6μg/L,定量下限分别为3、5μg/L,平均回收率分别在91.5%~95.8%和92.1%~96.3%之间,RSD分别在2.63%~4.23%和2.12%~4.52%之间。结论该法需血量少、提取效率高、干扰小、定量准确,适用于甲基汞和无机汞的内暴露健康影响评价和急性中毒实验室诊断测定。

Objective To establish a method for simultaneous determination of methylmercuryand inorganic mercury in blood with high performance liquid chromatography-tandem inductively coupled plasma mass spectrometry. Methods The blood samples were added with methanol to precipitate protein first,extracted by ultrasound at room temperature with a solution containing 0.05% （volume fraction） 2-mercaptoethanol,3 g/L L-cysteine and 0.1% （volume fraction）HCl,after the complex extraction from sample, methylmercuryand inorganic mercurywere separated by C 18 liquid chromatography column by using the mobile phasecontaining 5% （volume fraction）methanol,0.06 mol/L ammonium acetate,0.05% （volume fraction） 2- mereaptoethanol and 3 g/L L-cysteine in aqueous solution,and ICP-MS No gas mode was used for determination,external standard method was used for quantification. Results The linear regression equation of methylmercury and inorganic mercury in the linear range of 0.30-50 μg/L and 0.50-50 μg/L showed a good linear relationship （r〉0.999）, respectively. The limits of detection for methylmercury and inorganic mercury were 1 and 1.6 μg/L, respectively, and the lower limits of quantification were 3 and 5 μg/L, respectively. The average recoveries were between 91.5%-95.8% and 92.1%-96.3%, respectively, and the relative standard deviation（RSD, n=6） were between 2.63%-4.23% and 2.12%-4.52%, respectively. Conclusion This method needs less volume of blood sample, with high extraction efficiency, low interference and high accuracy, and is applicable to the determination of methylmercury and inorganic mercury for internal exposure health impact assessment and laboratory diagnosis of acute poisoning.