Determination of Antimony (III) and (V) in Natural Water by Cathodic Stripping Voltammetry with in-situ Plated Bismuth Film Electrode

摘要

A method is described for the sequential determination of Sb(III) and Sb(V) usingOsteryoung square wave cathodic stripping voltammetry. It employs an in-situ platedbismuth-film on edge-plane graphite substrate as the working electrode. Selectiveelectro-deposition of Sb(III)/Sb(V) is accomplished by applying a potential of –500 mV vsAg/AgCl, this followed by reduction to stibine at a more negative potential in the stripping step.Stripping was carried out by applying a square wave waveform between –500 and –1400 mV to the antimony deposited. The stripping peak current at –1150 mV is proportional to the concentration of Sb(III)/Sb(V). The calibration plots for Sb(III) were linear up to 12.0 μg L-1 depending on the time of deposition. The calibration plots for Sb(V) were linear up to 7.0 μg L-1,also depending on the time of deposition. The relative standard deviation in the determination of0.1 μg L-1 of Sb(III) is 4.0% (n = 5), and the limit of detection is as low as 2 ng L-1. In case of 0.1 μg L-1 Sb(V), the relative standard deviation is 3.0% (n = 5) and the detection limit also is 2 ng L-1. The method was applied to the analysis of river water and of sea water samples.