一种改进的测定水中硫酸盐的分光光度法研究

Study of an Improved Spectrophotometry Determining Sulfate in Water

相对于《水质硫酸盐的测定铬酸钡分光光度法》(HJ/T 342—2007),采取四点改进步骤:一是酸性铬酸钡代替铬酸钡悬浊液;二是以悬浊液定容,上清液用0.45μm滤膜过滤代替慢速滤纸过滤再定容操作;三是两次煮沸过程用超声加热代替;四是对大体积水样采用蒸发浓缩处理。对改进后的方法进行了检出限、精密度和准确度验证,试验结果表明:改进后的标准曲线相关系数达到0.9999;若样品不浓缩按照改进后方式进行测定,检出限为0.47 mg/L、测定下限为1.88 mg/L、相对误差为0.12%~1.25%;样品10倍浓缩后按照改进方法进行测定,检出限为0.05 mg/L、测定下限为0.20 mg/L、加标回收率为92.5%~105.3%,能够满足低浓度样品检测需求。

In this paper the improvement are divided into 4 steps based on the national standard"water quality sulfate determination of chromic acid pyridine specularity method"(HJ/T 342—2007),the first is to replace chromic acid suspension liquid with acidic chromium acid,then use the suspension liquid fixed capacity-on the clear liquid with 0.45μm filter filter instead of slow filter paper filtration operation,and then the two boiling processes are replaced by ultrasonic heating,and finally the large volume water samples are treated by evaporation and concentration.In this paper,the detection limit,precision and accuracy of the improved method are verified.The results show that the standard curve correlation coefficient of the improved method achieves 0.9999.If the sample is not concentrated in accordance with the improved method of determination,the detection limit is 0.47 mg/L,the determination limit is 1.88 mg/L and the relative error is 0.12%to 1.25%.After 10 times of the sample concentration,according to the improved method,the detection limit is 0.05 mg/L,the determination limit is 0.20 mg/L,the repertoire rate is between 92.5%to 105.3%,and the determination of the lower limit can meet the needs of low-concentration sample detection.