全自动阴离子表面活性剂测定仪与手工测定比较

Comparison of Determination between Automatic Anionic Surfactant Instrument and Manual Operation

为了使亚甲蓝分光光度法测定水体中阴离子表面活性剂的试验更节省劳动力并提高萃取效率,可采用全自动阴离子表面活性剂测定仪替代手工测定。该测定仪按照GB/T 7494—1987中的试验方法及步骤,测定饮用水、地表水、生活污水和工业废水中低浓度亚甲蓝活性物质时,其线性相关系数、准确度、稳定性、样品平行性以及加标回收率的测定结果均优于手工测定。测定仪的检出限为0.015μg/mL,符合国家标准要求的0.05μg/mL。手工测定的标准曲线相关系数平均值为0.9994,而全自动仪器的相关系数平均值为0.9998。在准确度测定中,质控液理论值为0.8025μg/mL,全自动仪器测定结果为0.8020μg/mL,手工测定结果为0.7760μg/mL,全自动仪器更接近真值。由于水样浓度本身低于方法检出限浓度,水样稳定性的手工测定和全自动仪器的检测结果相差无几,但全自动仪器的检测结果波动更小,稳定性更好;全自动仪器的回收率在97.87%~100.71%,而手工测定的加标回收率在92.20%~95.04%。

In order to save labor and improve extraction efficiency in the test of methylene blue spectrophotometric determination of anionic surfactants in water,an automatic anionic surfactant analyzer can be used instead of manual determination.According to test methods and procedures in GB/T 7494—1987,analyzer can measure low concentration methylene blue active substances in drinking water,surface water,domestic sewage and industrial wastewater.Determination results of linear correlation coefficient,accuracy,stability,sample parallelism and standard addition recovery rate of the analyzer were better than manual determination.Detection limit of analyzer was 0.015μg/mL,which met the national standard of 0.05μg/mL.Mean value of the correlation coefficient of standard curve determined by hand was 0.9994,while the mean value of the correlation coefficient of automatic instrument was 0.9998.In the accuracy measurement,the theoretical value of quality control solution was 0.8025μg/mL,the result of automatic instrument was 0.8020μg/mL,and the result of manual measurement was 0.7760μg/mL,and automatic instrument was closer to true value.Since the concentration of water sample itself was lower than the detection limit of method,the manual determination of the stability of water sample was almost the same as the test result of automatic instrument,but the test result of automatic instrument had less fluctuation and better stability.Recovery rate of automatic instrument was 97.87%~100.71%,while the recovery rate of manual determination was 92.20%~95.04%.