流动注射分光光度法测定水中六价铬

Determination of hexavalent chromium in water by flow injection spectrophotometric method

建立全自动流动注射分光光度法测定水中六价铬。流动注射分析仪设置参数为:洗针时间10 s;峰宽50 s;到达阀时间50 s;样品周期90 s;出峰时间22 s;进载流时间20 s;积分时长50 s;进样时间50 s。选择安全低毒、低碳环保、经济实用的无水乙醇替代丙酮作为显色剂的溶剂测定水中六价铬。六价铬的质量浓度在0.001~0.5 mL/L范围内与吸光度(峰面积)具有良好的线性关系,线性相关系数为0.9999,方法检出限为0.0003 mg/L。利用该方法测定水质环境标准样品中的六价铬,测定结果相对误差为0.15%~2.77%,相对标准偏差为0.15%~1.54%(n=6)。不同浓度的样品加标平均回收率为98.7%~101%。该方法简便快捷,灵敏度高,适用于水中六价铬的测定。

An automatic flow injection spectrophotometer was used for determination of chromium(Ⅵ)in water.The working parameter of flow injection analyzer were as follows:needle washing time was 10 s,peak width was 50 s,arrival valve time was 50 s,sample cycle was 90 s,peak time was 22 s,inlet current carrying time was 20 s;integration time was 50 s;injection time was 50 s.The mass concentration of hexavalent chromium had a good linear relationship with absorbance(peak area)in the range of 0.001-0.5 mL/L.The correlation coefficient was 0.9999,and the detection limit was 0.0003 mg/L.The relative error of water quality standard samples was 0.15%to 2.77%,and the relative standard deviation was 0.15%to 1.54%,respectively(n=6).The average recoveries of different concentrations were 98.7%to 101%.The method is simple,rapid,sensitive and suitable for the determination of hexavalent chromium in water.