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目的建立超声辅助萃取、高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)联用技术测定水产品中无机汞、甲基汞和乙基汞的方法。方法采用醋酸铵/L-半胱氨酸缓冲盐及甲醇(洗脱比例为95%∶5%)体系组成的流动相进行洗脱,对样品进行超声辅助萃取,使目标物与络合剂反应后进而提取分离,同时检测无机汞、甲基汞和乙基汞的浓度。结果确定最佳萃取时间为1 h,无机汞、甲基汞和乙基汞的分析时间分别为1.75 min、2.57 min和5.08 min,最低检出浓度分别为0.001 5 mg/kg、0.001 0 mg/kg和0.002 2 mg/kg,标准曲线回归方程相关系数(r)均>0.999。在低、中、高3种浓度下,无机汞、甲基汞、乙基汞的加标回收率分别为84.0%~100.4%、88.0%~99.2%、88.0%~102.6%,相对标准偏差(RSD)≤3.0%。用本方法检测鱼组织标准物质,测得值与标准值吻合,进一步验证了本方法的准确性。结论该方法前处理简单,提取效率高,精密度及准确度结果理想,可用于实际样品水产品中汞含量的测定。
Objective To establish a method for the determination of inorganic mercury, methylmercury and ethylmercury in aquatic products by ultrasonic-assisted extraction and high performance liquid chromatography-inductively-coupled plasma mass spectrometry (HPLC-ICP-MS). Methods A mobile phase consisting of ammonium acetate / L-cysteine buffer and methanol (95%: 5% elution) system was used for elution. The sample was subjected to ultrasonic-assisted extraction to react with the complexing agent And then extracted and separated, while detecting inorganic mercury, methylmercury and ethyl mercury concentration. The results showed that the optimal extraction time was 1 h, the analysis time of inorganic mercury, methylmercury and ethylmercury were 1.75 min, 2.57 min and 5.08 min, respectively. The minimum detectable concentrations were 0.001 5 mg / kg and 0.001 0 mg / kg and 0.002 2 mg / kg respectively, and the correlation coefficient (r) of the standard curve regression equation was> 0.999. The recoveries of inorganic mercury, methylmercury and ethylmercury were 84.0% ~ 100.4%, 88.0% ~ 99.2%, 88.0% ~ 102.6% at low, medium and high concentrations respectively. The relative standard deviations RSD) ≤3.0%. The method of detecting fish tissue reference material, the measured value and the standard value in line to further verify the accuracy of the method. Conclusions The method is simple in pretreatment, high in extraction efficiency, good in precision and accuracy, and can be used for the determination of mercury in real samples of aquatic products.