Electrochemical micropipette-tip for low-cost environmental applications: Determination of anionic surfactants through their interaction with methylene blue

TALANTA

卷:224

Article

Gonzalez-Lopez, Andrea¹  Costa-Rama, Estefania¹  Teresa Fernandez-Abedul, M.¹ 

[1] Univ Oviedo, Dept Quim Fis & Analit, Oviedo 33006, Spain

关键词: Micropipette-tip electrochemical cell;    Stainless-steel electrodes;    Electrochemical analysis;    Water analysis;    Sodium dodecyl sulphate;    Methylene blue;   

DOI  :  10.1016/j.talanta.2020.121732

来源: Elsevier

【 摘 要 】

Miniaturization is one of the main requirements in the design of portable devices that allow in-field analysis. This is especially interesting in environmental monitoring, where the time of the sample-to-result process could be decreased considerably by approaching the analytical platforms to the sampling point. We employed traditional mass-produced and low-cost elements (micropipette tips and pins) in an out-of-box application to generate an innovative and cost-effective platform for analytical purposes. We have designed simple and easy-to-use electrochemical cells inside polypropylene micropipette tips with three stainless-steel pins acting as the working, reference and counter electrodes of a potentiostatic system. The pin acting as working electrode was previously coated with carbon ink, meanwhile the rest were used unmodified. In this way, electrochemical in-the-tip measurements were done directly using low volumes (mu L) of sample. The devices showed good reproducibility, with a relative standard deviation of 7% (n = 5) for five different tip-based complete electrochemical cells. As a proof-of-concept, its utility has been probed by the determination of an anionic surfactant (sodium dodecyl sulphate, SDS) in water through its interaction with methylene blue (MB). Two different alternatives were presented based on the: 1) increase in the current intensity of the cathodic peak of MB due to the presence of SDS; 2) electrochemical determination of the MB remaining in the aqueous phase after extraction of the pair SDS-MB to an organic medium.

【 授权许可】

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