Trace vanadium analysis by catalytic adsorptive stripping voltammetry using mercury-coated micro-wire and polystyrene-coated bismuth film electrodes

Abstract

An electrochemical technique has been developed for ultra trace (ngL−1) vanadium (V) measurement. Catalytic adsorptive stripping voltammetry for V analysis was developed at mercury-coated gold micro-wire (MWE, 100 μm) electrodes in the presence of gallic acid (GA) and bromate ion. A potential of −0.275 V (vs Ag/AgCl) was used to accumulate the complex in acetate buffer (pH 5.0) at the electrode surface followed by a differential pulse voltammetric scan. Parameters affecting the electrochemical response, including pH, concentration of GA and bromate, deposition potential and time have been optimized. Linear response was obtained in the 0–1000 ngL−1 range (2 min deposition), with a detection limit of 0.88 ngL−1. The method was validated by comparison of results for an unknown solution of V by atomic absorption measurement. The protocol was evaluated in a real sample by measuring the amount of V in river water samples. Thick bismuth film electrodes with protective polystyrene films have also been made and evaluated as a mercury free alternative. However, ngL−1 level detection was only attainable with extended (10 min) deposition times. The proposed use of MWEs for the detection of V is sensitive enough for future use to test V concentration in biological fluids treated by the advanced oxidation process (AOP).

Individual and simultaneous determination of lead, cadmium, and zinc by anodic stripping voltammetry at a bismuth bulk electrode

“…Other Bi-based electrodes can be difficult and time-consuming to fabricate. BiFE films have been shown to be very fragile [15]. The BiBE is easily fabricated, cost-efficient, stable and robust, and is capable of yielding more reproducible results than other previously examined Bi-based electrodes.…”

Determination of trace vanadium(V) by adsorptive anodic stripping voltammetry on an acetylene black paste electrode in the presence of alizarin violet

“…The detection limit at the bismuth-coated glassy carbon electrode in the presence of chloranilic acid and bromate ion is about 0.20 lg dm À3 with an accumulation period of 10 min [23], 1572-6657/$ -see front matter Ó 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jelechem.2010.08.013 and the detection limit of ng dm À3 level was only attainable at a polystyrene-coated bismuth film electrodes with extended (10 min) deposition times [24]. The reported data show that the detection limit at the bismuth film electrodes is higher and need longer accumulation time than those reported for mercury electrodes.…”

“…Electrochemical methods are far less expensive and more portable than the aforementioned techniques. Specifically, adsorptive stripping voltammetry (AdSV) and catalytic adsorptive stripping voltammetry (CAdSV), based on the interfacial accumulation and voltammetric determination of metal complexes, has been shown useful for determining vanadium in various matrices [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]26]. Different complexing agents, such as 2,3-dihydroxynaphthalene [10], cupferron [11,12], chloranilic acid [13][14][15], catechol [16], 2-(5 0 -bromo-2 0 -pyridylazo)-5-diethylaminophenol [17,18], pyrogallol [19], 2-(2 0 -thiazolylaloz)-p-cresol [20], pyrocatechol violet [21] and solochrome violet RS [22] have been proposed.…”

“…However, the toxicity of mercury and mercury salts employed for the preparation of mercury film limits the usage of them in the analytical practice and excludes them from the out-of-laboratory applications. Recently, less toxic bismuth film electrodes [23,24] were applied to V(V) determination. The detection limit at the bismuth-coated glassy carbon electrode in the presence of chloranilic acid and bromate ion is about 0.20 lg dm À3 with an accumulation period of 10 min [23], 1572-6657/$ -see front matter Ó 2010 Elsevier B.V. All rights reserved.…”

Study on simultaneous measurements of trace gallium(III) and germanium(IV) by adsorptive stripping voltammetry using mercury film electrode

“…Other recent mercury film electrodes in the determination of trace beryllium at the mercury film electrode [46], trace vanadium at the mercury-coated micro-wire and polystyrene-coated bismuth film electrodes [47], and oxcarbazepine at the silver nanoparticle-modified carbon screen-printed electrodes in stripping voltammetry were applied [48].…”