摘要
目的建立食盐中硫酸根的间接络合滴定检验法。方法样品经前处理后加钡镁混合液,在加热条件下,溶液中硫酸根与钡离子反应生成难溶于水的硫酸钡,过量的钡离子在镁离子的置换作用下,以铬黑T为指示剂,以乙二胺四乙酸二钠(EDTA-Na2)滴定,根据钡离子浓度变化计算硫酸根含量。结果加标前后,本方法回收率(96.2%~100.1%)及精密度(0.6%~2.2%)较国家标准方法回收率(85.1%~88.5%)及精密度(1.6%~6.7%)明显提高。结论相比于国家标准方法,本方法以经济实用的氯化镁代替原方法中乙二胺四乙酸二钠镁,节约成本;合并氯化钡与氯化镁为钡-镁混合液,简化操作步骤;添加60℃水浴加热,提升生成硫酸钡的反应效率,提高检测回收率。试剂成本低,操作简便,精密度高,准确性好,更利于推广普及。
Objective To investigate the determination of sulfate radical in salt sample by indirect complexometric titration.Methods After heating and being treated with barium-magnesium aqueous solution,sulfate radical in the sample was precipitated in poorly water-soluble BaSO4,and the excess barium ion was titrated with EDTA-Na2,using EBT as an indicator.Sulfate concentration was determined by calculating the variation of Ba ion content.Results The pre-spiked and the pro-spiked recovery rate(96.2%-100.1%)and precision(0.6%-2.2%)of this method were significantly improved compared to the recovery rate(85.1%-88.5%)and precision(1.6%-6.7%)of the national standard method.Conclusion Compared with the standard method,this method is simple and low cost with relatively high sensitivity and accuracy,which is easy to be popularized.
作者
温权
李可
梁肇海
WEN Quan;LI Ke;LIANG Zhao-hai(Futian District Center for Disease Control and Prevention,Shenzhen,Guangdong 518040,China)
出处
《中国卫生检验杂志》
CAS
2020年第1期24-25,30,共3页
Chinese Journal of Health Laboratory Technology
基金
深圳市科创委项目(JCYJ20150402150147470)
深圳市福田区卫生公益科研项目(FTWS2017051)
关键词
食盐
硫酸根
间接配合滴定法
Salt
Sulfate radical
Indirect complexometric titration
