原子荧光法测定食盐中的总汞及总砷

Determination of Total Mercury and Arsenic in Salt by Atomic Fluorescence Spectrometry

目的采用原子荧光光度法分别测定食用盐中砷、汞的含量,了解食盐的砷、汞污染物安全现状和再污染现状。方法 2018-04/08间采集南充市每个区(县)盐样各100份,总计900份。食盐样品直接加水溶解定容,砷测定以制盐工业通用试验方法为依据,砷在硫脲预还原剂作用下还原成As3+。汞测定参考GB 5009.17-2014和GB/T 5750.6-2006两个方法,汞在溴酸盐的作用下全部转为Hg2+。结果砷检出限为0.003 0 mg/kg,RSD为6.71%,加标回收率在96.0%~102.8%之间。汞检出限为0.000 10 mg/kg,RSD为9.15%,加标回收率在98.8%~112.0%之间。样品测定结果砷含量均低于0.016mg/kg,汞含量均低于0.019 mg/kg,砷、汞含量均未超标。结论此方法操作简单,结果准确,非常适合食用盐中砷、汞的测定,调查得出砷、汞污染物均符合国家污染物限值要求,绿色安全。

Objective To determinate the arsenic and mercury in edible salt by using the method of atomic fluorescence spectrometry and understand the safety status and re-polluting status of arsenic and mercury pollutants in salt.Methods Salt samples were collected about 100 samples for each district(county)in Nanchong City from April to August 2018,which were 900 samples in total.The salt sample was directly added with water to dissolve the volume,arsenic determination was in accordance with the general test method of the salt industry,and arsenic was reduced to As3+under the action of thiourea pre-reducing agent.Mercury,which was converted to Hg2+under the action of bromine,was measured based on the GB5009.17-2014 and GB/T 5750.6-2006.Results The detection limit of arsenic was 0.003 0 mg/kg,the RSD was 6.71%,and the recovery rate ranged from 96.0%to 102.8%.The mercury detection limit was 0.000 10 mg/kg,the RSD was 9.15%,and the spiked recovery rate varied from 98.8%to 112.0%.The arsenic content of the samples was less than 0.016 mg/kg,and the mercury content was less than 0.019 mg/kg.The arsenic and mercury contents were not exceeded.Conclusion This method was simple,accurate and extremely suitable for the determination of mercury and arsenic in edible salt.The investigation finds that arsenic and mercury pollutants are in line with the national pollutant limit requirements and are green and safe.