Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil.
Electrophoresis. 2014 Mar;35(6):864-9. doi: 10.1002/elps.201300463. Epub 2013 Dec 23.
The simultaneous determination of cationic, anionic, and neutral analytes in a real sample was demonstrated by coupling electrochemical (EC) derivatization with counter-EOF CE-C(4) D. An EC flow cell was used to oxidize alcohols from an antiseptic mouthwash sample into carboxylic acids at a platinum electrode in acid medium. The carboxylates formed in the derivatization process and other sample ingredients, such as benzoate, saccharinate, and sodium ions, were separated in counter-flow mode and detected in one run in Tris-HCl buffer, pH 8.6. Fewer than 5 min were needed to complete each analysis with the automated flow system comprising solenoid pumps for the management of solutions. Insights into the electrochemistry of benzoic acid, present in the sample matrix, were also gained by EC-CE-C(4) D; more specifically, by applying potentials higher than 1.47 V to the platinum electrode, some formiate and minute amounts of salicylate were detected.
通过将电化学（EC）衍生化与反电渗流毛细管电泳-C（4）D 相结合，实现了对真实样品中阳离子、阴离子和中性分析物的同时测定。在酸性介质中，使用 EC 流动池在铂电极上将防腐剂漱口水中的醇氧化成羧酸。在衍生化过程中形成的羧酸盐和其他样品成分（如苯甲酸盐、糖精盐和钠离子）在逆流模式下分离，并在 Tris-HCl 缓冲液，pH8.6 中一次运行中进行检测。使用自动流系统，包括用于溶液管理的电磁阀泵，每个分析的时间不到 5 分钟。通过 EC-CE-C（4）D 还深入了解了存在于样品基质中的苯甲酸的电化学；更具体地说，通过向铂电极施加高于 1.47 V 的电势，检测到一些甲酸盐和微量的水杨酸酯。
