Department of Chemistry, Kumamoto University, Kumamoto 860-8555, Japan.
Department of Chemistry, Kumamoto University, Kumamoto 860-8555, Japan.
Talanta. 2018 Apr 1;180:176-181. doi: 10.1016/j.talanta.2017.12.054. Epub 2017 Dec 18.
Preconcentration is an effective way to improve analytical sensitivity. Many types of methods are used for enrichment of ionic solute analytes. However, current methods are batchwise and include procedures such as trapping and elution. In this manuscript, we propose in-line electrodialytic enrichment of ionic solutes. The method can enrich ionic solutes within seconds by quantitative transfer of analytes from the sample solution to the acceptor solution under an electric field. Because of quantitative ion transfer, the enrichment factor (the ratio of the concentration in the sample and to that in the obtained acceptor solution) only depends on the flow rate ratio of the sample solution to the acceptor solution. The ratios of the concentrations and flow rates are equal for ratios up to 70, 20, and 70 for the tested ionic solutes of inorganic cations, inorganic anions, and heavy metal ions, respectively. The sensitivity of ionic solute determinations is also improved based on the enrichment factor. The method can also simultaneously achieve matrix isolation and enrichment. The method was successively applied to determine the concentrations of trace amounts of chloroacetic acids in tap water. The regulated concentration levels cannot be determined by conventional high-performance liquid chromatography with ultraviolet detection (HPLC-UV) without enrichment. However, enrichment with the present method is effective for determination of tap water quality by improving the limits of detection of HPLC-UV. The standard addition test with real tap water samples shows good recoveries (94.9-109.6%).
预浓缩是提高分析灵敏度的有效方法。有许多类型的方法可用于富集离子型溶质分析物。然而，目前的方法是分批进行的，包括捕获和洗脱等步骤。在本文中，我们提出了在线电渗析富集离子型溶质的方法。该方法可以在几秒钟内通过电场将分析物从样品溶液定量转移到接受溶液中，从而实现对离子型溶质的富集。由于定量的离子转移，富集因子（样品中浓度与获得的接受溶液中浓度之比）仅取决于样品溶液与接受溶液的流速比。对于测试的无机阳离子、无机阴离子和重金属离子的离子型溶质，浓度比和流速比的比值高达 70、20 和 70 时是相等的。基于富集因子，离子型溶质测定的灵敏度也得到了提高。该方法还可以同时实现基体隔离和富集。该方法成功地应用于测定自来水中痕量氯乙酸的浓度。如果不进行富集，常规的带有紫外检测的高效液相色谱（HPLC-UV）无法检测到规定的浓度水平。然而，通过本方法进行富集可以有效提高 HPLC-UV 的检测限，从而用于检测自来水的质量。用实际的自来水样品进行的标准添加测试显示出良好的回收率（94.9-109.6%）。
