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目的运用MA-3000全自动测汞仪,结合运用还原催化和金汞齐富集技术,建立直接测定固体、液体食品中汞含量的方法。方法将固体食品样品用粉碎机粉碎之后精确称取适量,液体样品准确量取一定体积,应用全自动测汞仪建立汞标准曲线,直接测定食品样品的汞含量。结果经试验确定食品样样品直接测定汞,测定优化条件为分解温度850℃,分解时间为2 min。在最佳实验条件下,标准汞溶液在0.0 ng~200.0 ng时,呈现较好的线性关系,标准曲线相关系数≥0.999 8,加标回收实验汞回收率为96.6%~104.9%,测定结果的相对标准偏差为2.87%~3.47%,方法检出限为0.005 5 ng。结论该方法与原子荧光法比较,2种方法差异无统计学意义。本方法操作简便、快捷、准确、灵敏、重复性好,适合快速批量直接进样测定蔬菜、海产品、谷物、人体尿液、头发中总汞,结果令人满意。
Objective To establish a direct method for the determination of mercury in solid and liquid food by using MA-3000 automatic mercury analyzer and combined with reduction catalysis and gold amalgam enrichment technology. Methods The solid food samples were crushed with a crusher and accurately weighed. The accurate volume of the liquid sample was taken as a certain volume. The mercury standard curve was established by the automatic mercury analyzer and the mercury content in the food samples was directly determined. Results Direct determination of mercury in food samples was confirmed by experiments. The optimal conditions for the determination of mercury were decomposition temperature of 850 ℃ and decomposition time of 2 min. Under the optimal experimental conditions, the standard mercury solution showed a good linearity at the concentration range of 0.0 ng ~ 200.0 ng, the correlation coefficient of the standard curve was ≥0.999 8, the recoveries of mercury in the spiked recovery tests ranged from 96.6% to 104.9% The relative standard deviations were 2.87% ~ 3.47%. The detection limit was 0.005 5 ng. Conclusion Compared with atomic fluorescence spectrometry, there is no significant difference between the two methods. The method has the advantages of simple, fast, accurate, sensitive and good repeatability, and is suitable for rapid batch direct injection for determining total mercury in vegetables, seafood, cereal, human urine and hair with satisfactory results.