Wen-Lun Chang, Annamalai Senthil Kumar, Shu‐Ping Wang
Mar 20, 2016
Citations
0
Influential Citations
5
Citations
Journal
Electrochimica Acta
Abstract
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 H2SO4 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.