生活饮用水中阴离子合成洗涤剂检测方法的改进

Improving method of anionic synthetic detergent test in drinking water

目的建立一种简便、快捷、可靠的测定生活饮用水中阴离子合成洗涤剂的方法,以改进GB/T 5750.4—2006中的亚甲蓝分光光度法。方法用100 ml带刻度聚乙烯离心管涡旋萃取代替分液漏斗振荡式萃取,用亚甲蓝分光光度法对标准样品及水样进行测定,样品不调pH值,无需酸洗,仅经萃取一次,静置分层后,无需将水相和有机相完全分离,采用10 ml带针头注射器快速插入离心管底部吸取有机相转移入比色皿中进行测定。结果在0μg^40.00μg线性关系良好,线性相关系数达到0.9996,方法的检出限为0.05 mg/L,精密度RSD<1.0%,样品加标回收率在98.0%-100.0%,测试能力验证样品|Z|<1,与标准方法相比,本方法单个样品前处理时间可由90 min缩短至22 min。结论该方法操作简便、快捷,准确度和精密度与国家标准GB/T 5750.4—2006检测结果无显著差异。

Objective A simple, quick and reliable method is established for testing anionic synthetic detergent in drinking water, in order to improve the Chinese standard method(GB/T 5750.4-2006). Methods The funnels were replaced by 100 ml ruler graduated polyethylene centrifuge tubes, without adding acid to regulate pH, the standard samples and water samples were determined by methylene blue spectrophotometric method. Only single extraction process is needed, and after stratification, a 10 ml syringe needle is quickly inserted into the bottom of the centrifuge tube to aspirate the organic phase and transfer it to colorimetric utensil for testing. Results The absorbance of anionic synthetic detergent contents from 0 μg to 40 μg showed a linear relationship with a correlation coefficient(r) of 0.999 6, while the limit of detection was evaluated to be 0.05 mg/L, the recoveries of the samples ranged from 98.0% to 100.0%, the precision of the method was demonstrated by relative standard deviations(RSD) of <1.0%, the |Z| value was <1 for testing a capability validation sample;compared with standard method, the pre-treatment time can be shorten from 90 min to 22 min. Conclusion This method is simple, quick and reliable, and the recoveries and relative standard deviations are comparable to those obtained with GB/T 5750.4-2006 method.