测定饮水中阴离子合成洗涤剂时干扰物的去除

Determination of Anionic Surfactant Interfering Substances in Drinking Water

目的筛查影响流动注射法测定饮用水中阴离子合成洗涤剂准确度的干扰物,研究掩蔽干扰物的最佳物质与条件。方法根据水中常见的25种化学可添加物质,参照《生活饮用水卫生标准》(GB 5749-2006)最高限值量,采用标准物质配制含不同成分的水样,进行干扰物实验筛查。针对筛查结果,进行掩蔽效果实验,探索最佳的掩蔽剂和最佳掩蔽条件实验。结果实验表明,水体中钙、镁离子是影响流动注射法测定饮用水中阴离子合成洗涤剂准确度的最大干扰物,调节水样p H=10,添加EDTA-2Na可掩蔽其干扰。本方法与《生活饮用水标准检验方法》中亚甲蓝分光光度法比较,两方法的加标回收率经统计学检验无显著性差异(P>0.05)。结论添加适量EDTA-2Na可掩蔽水体中钙镁离子的干扰,从而改进流动注射法测定饮用水中阴离子合成洗涤剂。该方法分析效率高,灵敏度、精密度、准确度均满足国家标准要求。

Objective To screen disruptors in the determination of anionic surfactant in drinking water tested by flowing injection analysis, and to study the best material and condition for masking disruptors. Methods In the experiment of screening disruptors, reference materials according to 25 common chemical substances in water were used to prepare water samples, and the concentration of each material was based on the maximum limits for drinking water in ＂Standards for Drinking Water Quality＂（ GB 5749 -2006）. The optimal masking agents and the best ex- perimental condition were based on the screening results. Results Calcium and magnesium were the most impor- tant disruptors in the determination of anions surfactant in drinking water by flow injection analysis. The disruption of calcium and magnesium in water could be masked by adding EDTA - 2Na and adjusting to pH = 10. The recov- ery rate of this method was not statistically different from the national standard method （ P 〉 0. 05 ）. Conclusions The interference of calcium and magnesium in the determination of anionic surfactants in drinking water by flow in- jection analysis could be masked by adding suitable amount of EDTA - 2Na. The merit of this method was high in efficiency, sensitivity and precision, and the accuracy of this method can meet the requirements of national exami- nation standard.