Selective flow injection detection of zinc phenolsulfonate as oxidized intermediates using a pre-anodized screen printed carbon ring-disk electrode coupled with a dual electrode system. (20th March 2016)

• Record Type: Journal Article
• Authors: Chang, Wen-Lun; Kumar, Annamalai Senthil; Wang, Shu-Ping; Yang, Chao-Hsun; Shih, Ying
• Is Part Of: Electrochimica acta. Volume 195(2016)
• Page Start: 199
• Page End: 207
• Publication Date: 2016-03-20
• Subjects: Zinc phenolsulfonate -- Bipotentiostat flow injection analysis -- Screen printed ring-disk electrode -- Electro-oxidized intermediates -- Cosmetic sample; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.02.146
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: Pre-anodized screen-printed carbon ring/disk was used as a detector for phenol detection. Zinc phenolsulfonate (ZPS) is taken as an analytical model for the flow injection analysis. ZPS is detected at ring part of the detection scheme as oxidized phenolic intermediates. No surface fouling and phenol electro-polymerization problems were noticed. The proposed system was validated for the analysis of ZPS in cosmetic samples. Abstract: Phenol and its derivatives are important aromatic compounds and that have been widely used in pharmaceutical, cosmetic, industrial applications for many years. Selective and direct detection of phenol, especially monophenol, is a challenging research interest in analytical chemistry. Although electrochemical methodology offers simple and straightforward route for phenol oxidation reaction, complications like tarry polymeric products formation and electrode surface fouling problems limit the electrodes for further extension to practical applications. In order to solve the problems, indirect electrochemical and biosensor based protocols have been often employed. Here in, we report an elegantly designed flow-injection analysis coupled dual electrochemical detector (FIA-DECD) made-up off a screen-printed carbon ring (SPCE-R*) and disk (SPCE-D*), which have been pre-anodized at 2 V vs Ag/AgCl at 300 s in pH 7 phosphate buffer solution, for direct and simple detection of monophenols using 0.05 M H2 SO4 solution as a carrier solution. In this protocol, phenol got first electro-oxidized on SPCE-D* (disk part) at Eapp = 1.5 V vs Ag/AgCl to quinone like intermediates (1, 2-dihydroxy, 1, 4-dihydroxy and 1, 2, 4-trihydroxy benzene) that have been subsequently detected on SPCE-R* at Eapp = 0.1 V vs Ag/AgCl. The SPCE-D* was found to trap fraction of the intermediates (quinone like derivatives) on its surface. Discreet electrochemical and physico-chemical characterizations of the phenol exposed SPCE-D* by cyclic voltammetry, Raman spectroscopy and Gas chromatography coupled mass spectroscopy confirmed the formation of different types of quinone like products on its surface. A complicated phenolic compound, zinc phenolsulfonate (ZPS), which has been widely used as an antimicrobial agent in cosmetics, was taken as a model phenolic system for the FIA-DECD. Selective detection of ZPS in different cosmetic real samples has been demonstrated as a validation for the present protocol.