Laser activated voltammetry: application to the determination of phenol in aqueous solution at a glassy carbon electrode

Abstract

Clean electrode surfaces can be achieved during the electrolysis of otherwise passivating species in aqueous and other solutions by means of surface ablation using a 10 Hz pulsed Nd+YAG 532 nm laser. This ability to remove passivating electrolytically generated layers on a glassy carbon electrode in a channel flow cell was shown by an investigation of the stripping peaks formed from the electrogeneration of the neutral forms of methyl viologen and heptyl viologen during reduction in aqueous solution of the corresponding di-cations. Next, laser ablation voltammetry was conducted for the oxidation of phenol in aqueous solution. Steady state voltammograms were obtained with well defined mass transport limited currents contrasting with the current peaks seen under dark scans where the formation of a polymerised layer on the electrode surface ultimately leads to electrode passivation under flow conditions. Square wave voltammetry was then used to detect phenol under no-flow conditions using a laser intensity of 0.1 W cm 22 . A linear dependence of the peak current on the concentration was found with a detection limit of phenol of 2 mM.

Advances in the Voltammetric Analysis of Small Biologically Relevant Compounds

“…This is typified by attempts to determine phenolic species (i.e., tyrosine) through the electrooxidation of the hydroxyl functionality. Polymeric material can be deposited on the electrode surface (4,5) and although profitably exploited as a method of electrode modification (6,7), the cumulative decrease in electrode response tends to preclude this route as a means of quantifying the original, monomeric, species. Similar behavior is also observed with aromatic amines and heterocyclics such as pyrroles, thiophenes, and indoles (6 -8).…”

Stabilization of the voltammetric response of organic analytes with self-passivating electrode reactions: Synergistic effect of surfactants and high buffer strength

“…The main symptom hereof is usually a fall-off or even a complete loss of the signal during repeated measurements with the same electrode. As discussed in [1], several strategies for counteracting the fouling problem have been proposed, including laser ablation [2,3], potential cycling or preanodization [4,5] of the working electrode, but these approaches either necessitate the use of more complex instrumentation or have other drawbacks [1].…”

A kinetic method for para-nitrophenol determination based on its inhibitory effect on the catalatic reaction of catalase

“…This fact allowed us to develop a kinetic method for the determination of para-nitrophenol, applicable to waste water samples. Other methods are currently used for the determination of phenols including UV-VIS spectrophotometry [20][21][22], potentiometric [23,24] and amperometric methods [25,26] or high -performance chromatographic techniques [27][28][29]. Not so common methods like non -aqueous capillary electrophoresis [30] or enzyme -linked immunosorbent assay [19,31] were also employed for the determination of phenols.…”