Trace Determination of Chromium by Square‐Wave Adsorptive Stripping Voltammetry on Bismuth Film Electrodes

Abstract

This works reports the use of adsorptive stripping voltammetry (AdSV) for the trace determination of chromium on a rotating-disk bismuth-film electrode (BFE). During the reductive accumulation step, all the chromium species in the sample were reduced to Cr(III) which was complexed with cupferron and the complex was accumulated by adsorption on the surface of a preplated BFE. The stripping step was carried out by using a square-wave (SW) potential-time voltammetric signal. Electrochemical cleaning of the bismuth film was employed, enabling the same bismuth film to be used for a series of measurements in the presence of dissolved oxygen. The experimental variables as well as potential interferences were investigated and the figures of merit of the method were established. Using the selected conditions, the 3s limit of detection for chromium was 100 ng L À1 (for 120 s of preconcentration) and the relative standard deviation was 3.6% at the 2 mg L À1 level (n ¼ 8). Finally, the method was applied to the determination of chromium in real samples with satisfactory results.

Speciation of Trace Levels of Chromium with Bismuth Modified Pyrolyzed Photoresist Carbon Electrodes

“…The calculated D L is comparable or lower than those obtained with other electroanalytical methods [23][24][25].…”

“…A nalyses of Cr(VI) by A dCSV with mercury electrodes have been performed using different complexing agents such as diethylene triamine pentaacetic acid (D TPA ) [18,19], cupferon [20] or pyrocatechol violet (PCV) [21,22]. R ecently, bismuth modified electrodes have been proposed as a valid alternative to H g also for the A dCSV of Cr(III) and Cr(VI), using the above cited ligands [23][24][25].…”

A Decade with Bismuth‐Based Electrodes in Electroanalysis

“…The application of BiEs to medical samples has included monitoring the release of zinc from pancreatic islets [43], the determination of cobalt and nickel in aqueous humor (from the human eye) and cerebrospinal fluid [85], the analysis of blood samples [24,41,133] and the analysis of urine [23,38,87]. Great diversity exists in the use of BiEs for the determination of heavy metals in food samples including wine and fruit juice [28,37,74,139,150,169,188], various vegetable samples (potato and maize [77], sugar cane [142], garlic [144], cabbage, lettuce and celery [160]), meat samples (sausage, tuna and sardines [186]) and other samples including tomato sauce [28], tea leaves [64,116] and tobacco [33]. While various natural and marine water samples make up the bulk of environmental samples, BiEs have also been applied to complex sewage samples [128,181], plant extracts [75,86], fertilizer samples [103,145] and a number of soil samples [33,34,39,49,55,104,141].…”

“…In this year of further expansion, the respective publication output had rapidly grown [31 -46], reflecting also the results of several newly established teams [25 -30]. Besides continuing investigations in home laboratories of the Slovenian pioneers [31,32,34], in the Czech Republic, Poland [37, 44 -46], Greece [33,35,36,38] and Italy [42], the premiere reports arrived from the U.K. [39 -41] and another locality in the U.S. (Cincinnati [43]). In a collection of sixteen publications, one could find very diverse contributions -from optimizations and validations of newly developed methods for trace metal analysis [33 -35, 44, 45], up to the first real-life application of a BiFE in biological/clinical analysis [43].…”

Flow-Through Chronopotentiometry in Waste Water Analysis

“…Only Cr(VI) species give this product which enables the selective determination of chromate also in the presence of Cr(III). To bypass the use of the toxic mercury electrode, bismuth-film electrodes have recently been used (Chatzitheodorou et al, 2004;Lin et al, 2005). In-electrode coulometric titrations facilitate the direct determination of Cr(VI) in water samples.…”