铬酸钡分光光度法测定水中硫酸盐含量

Determination of Sulfate in Water by Barium Chromate Spectrophotometry

硫酸盐是水质常规分析中重要项目之一,常用的铬酸钡分光光度法(HJ/T 342-2007)在使用中常会出现校准曲线线性不佳、差异性大,测试结果不准等问题。对标准方法的关键试验过程进行补充讲解,改进显色液过滤方式,并通过样品测试进行验证分析。结果表明,硫酸盐质量浓度在5~200mg/L范围内线性关系良好,线性相关系数r>0.999,运用统计学原理对不同时间测试校准曲线进行检验,结果显示无显著性差异;实际样品精密度试验相对标准偏差(RSD,n=6)为0.47%~0.61%,加标回收率为96.5%~102.5%;标准样品测试结果在1σ以内,说明改进后的方法具有可靠的操作性和准确性。

The sulfate content is an important index in the routine analysis of water quality.The Barium Chromate Spectrophotometry(HJ/T 342-2007)which commonly be used often has some problems,such as poor linearity of calibration curve,great difference,and inaccurate test results.In this paper,the key test process of the standard method was supplemented,and the filtration method of the chromogenic liquid was improved.Finally,the method was verified and analyzed by actual samples.The results showed that mass concentration of sulfate had a good linear relationship within the range of 5~200 mg/L.The linear correlation coefficient r>0.999.The calibration curves which obtained in different time were checked by statistical principle.The results showed that there was no significant difference.The relative standard deviation(RSD,n=6)of determination results for the actual sample were between 0.47%and 0.61%.The recoveries were between 96.5%and 102.5%.And the test of standard sample was less than 1σ.As a result,the improved method is proved to be reliable in operation and accuracy.