正交设计优化石墨炉原子吸收光谱法测定食用盐中的微量铅

Determination of trace lead in edible salt by graphite furnace atomic absorption spectrometry optimized by orthogonal test

中文关键词:  食用盐  石墨炉原子吸收光谱法  铅  正交试验

英文关键词:edible salt  graphite furnace atomic fluorescence spectrometry  lead  orthogonal test

中文摘要:

      目的 建立并优化测定食用盐中微量铅(Pb)的石墨炉原子吸收光谱法(graphite furnace atomic absorption spectrometry, GFAAS)。方法 利用磷酸二氢铵-酒石酸作为基体改进剂, 通过正交试验优化GFAAS测定食盐中Pb的条件, 包括灰化温度、原子化温度、基体改进剂种类。结果 GFAAS最佳测定条件为: 灰化温度200 ℃, 原子化温度2000 ℃, 10 μg/L磷酸二氢铵-10 μg/L酒石酸混合溶液作为基体改进剂。在该条件下, Pb在0.0~50.0 μg/L范围内线性关系良好, 相关系数r=0.9979, 方法检出限为0.10 μg/L, 测定下限为 0.5 mg/kg。将方法应用于市售湖盐、海盐、井矿盐等7种样品中Pb含量的测定, 相对标准偏差为3.9%~8.0%, 加标回收率为93.7%~108.8%。结论 本研究所建立的方法适用于食盐中微量Pb含量的快速准确定量检测。

英文摘要:

      Objective To establish and optimize a method for the determination of trace lead (Pb) in edible salt by graphite furnace atomic absorption spectrometry (GFAAS). Methods Ammonium dihydrogen phosphate-tartaric acid was used as matrix modifier, the experimental conditions of determination of Pb in edible salt by GFAAS including ashing temperature, atomic temperature and types of ascorbic acid were optimized by orthogonal test. Results The optimal determination conditions of GFAAS were as follows: Ashing temperature 200 ℃, atomization temperature 2000 ℃, 10 g/L ammonium dihydrogen phosphate-10 g/L tartaric acid were used as matrix modifier. Under this conditions, Pb had good linearity in the range of 0.0?50.0 μg/L, with the correlation coefficient r=0.9979, the detection limit of 0.10 μg/L, and the minimum quantitative detection limit was 0.5 mg/kg. The proposed method was applied to the determination of lead content in 7 kinds of edible salt samples, the relative standard deviations were 3.9%?8.0%, the recoveries of samples were 93.7%?108.8%. Conclusion The method established in this study is suitable for rapid and accurate determination of trace Pb content in table salt.