在线微孔膜双萃取-流动注射光度法测定水中阴离子表面活性剂的研究

采用在线微孔膜双萃取-流动注射光度法测定了水中的阴离子表面活性剂.方法基于亚甲基蓝与阴离子表面活性剂作用生成的盐类(λ_(max)=650 nm),可被氯仿萃取,采用在线双微孔膜液液萃取相分离器,优化了流路参数、萃取模块的流路尺寸和微孔膜的孔径.方法的线性范围为25～1000 μg/L,线性相关系数r≥0.999;检出限为4.3 μg/L;不同浓度的相对标准偏差(n=7)为0.7%～6.0%;实际水样的加标回收率为96%～110%;样品测定频率为18样/h.利用本方法分别测定了2个实际水样和2个国家标准参考物质中的阴离子表面活性剂,结果令人满意.

Determination of Anionic Surfactants in Waters by On-line Double Microporous Membrane Extraction-Flow Injection Spectrophotometry

Anionic surfactants in waters were determined using on-line double microporous membrane extraction-flow injection analysis method. This method was based on the extraction of the ion-association complex (λ_(max)=650 nm) which formed from methylene blue cation and anionic surfactants. The on-line double microporous membrane liquid-liquid extraction phase separators were adopted. Optimization of variables of the flow injection manifold, groove mechanical dimension of the phase separator, and pore size of the membrane was performed. The proposed method had a linear range of 25.0-1000.0 μg/L(r≥0.999). The detection limit was 4.28 μg/L. The relative standard deviation(n=7) of different concentration was 0.7%-6.0%. The recovery was between 96%-110% and the sample throughput was 18 h-1. The method was applied to the analysis of standard Reference materials with satisfactory results. For practical application, two water samples were analyzed with the established method.