Influence of Nafion Coatings and Surfactant on the Stripping Voltammetry of Heavy Metals at Bismuth-Film Modified Carbon Film Electrodes

Abstract

Nafion polymer coated bismuth-film-modified carbon film electrodes have been investigated for reducing the influence of contaminants such as surfactants in the anodic stripping voltammetry of trace metal ions. The influence of the coating on electrode response has been tested with both ex situ and in situ bismuth film deposition, with and without the polymer coating. The electrode assemblies and interfacial characteristics in the presence of the non-ionic surfactant Triton-X-100 have been probed with electrochemical impedance spectroscopy. The Nafion coating successfully decreases the adsorption of Triton on the bismuth film surface, and demonstrates that this strategy allows measurement of these trace metals in environmental samples containing surfactants.

Characterization and Application of Bismuth‐Film Modified Graphite‐Polyurethane Composite Electrodes

“…At GPCE in situ modified with Bi films, surface active materials do not have as strong an influence as was reported previously in [34] at BiF deposited on carbon film electrodes. This leads us to conclude that surface active materials Table 2.…”

“…The fact that the GPCE modified with a Bi film is extremely sensitive to Zn, is unlike the other BiFEs reported [33 -35]. Commonly, the electrode sensitivity to Zn is limited by hydrogen evolution since Zn is accumulated at À 1.4 V and stripped at À 1.1 V, where H 2 evolution starts and interferes with both the preconcentration and the stripping processes [33,34]. Thus glassy carbon electrodes modified with bismuth films are most sensitive either to Cd or to Pb [33,35].…”

“…The selected spectra are presented as complex plane plots ( Figure 3a) and imaginary impedance vs. logarithm of frequency (Figure 3b), a plot which represents a powerful way of examining the time constants of interfacial processes, since the peaks in the plots correspond to when wRC ¼ 1 for situations where charge separation (capacitance, C) and charge transfer (resistance, R) are in parallel, with w the frequency of the voltage perturbation in radians [33,34]. The spectra at À 1.4 and at À 1.1 V (the latter not shown) give evidence that, besides the other processes (metal preconcentration and Zn reoxidation), some hydrogen evolution takes place, since the spectra in the low frequency region do not give stable values, due to the formation of a tiny quantity of H 2 gas bubbles, especially visible at À 1.4 V. Misshaped semicircles are obtained (Figure 3a) and the impedance values are much lower compared with other potentials studied.…”

Modified carbon-containing electrodes in stripping voltammetry of metals. Part II. Composite and microelectrodes

“…The use of the following commercially available electrode materials is reported in the literature: pencil lead [1][2][3]; spectral [4,5], pyrolitic [6], and felt [7] graphites; carbon glass ceramic [8][9][10]; nonwoven graphite films [11]; carbon film resistors; and switches [12][13][14][15][16]. In most cases, electrodes of these materials are modified by metal films (mercury, copper, and bismuth), molecularly imprinted TiO 2 [17].…”

“…Prospects for the future development of solid-state modified electrodes are considered. [12][13][14][15][16]. In most cases, electrodes of these materials are modified by metal films (mercury, copper, and bismuth), molecularly imprinted TiO 2 [17].…”