Adsorptive Cathodic Stripping Voltammetric Determination of Hexavalent Chromium

Abstract

Abstract A sensitive and selective voltammetric method of analysis is developed for determination of trace amounts of Cr(VI) ions in neutral nitrate phosphate media. This method is based on controlled adsorptive preconcentration of chromium species at Hanging Mercury Drop Electrode (HMDE). The adsorptive stripping response was evaluated with respect to preconcentration time and potential and dependence on composition of supporting electrolyte. As low as 5x10−9 mol L−1 (0.25 μg/L) and 1x109 mol L−1 (0.52 μg/L) Cr(VI) can be detected using Cathodic Linear Sweep Stripping Voltammetry (CLSSV) and Differential Pulse Cathodic Stripping Voltammetry (DPCSV), respectively. The precision of the method is satisfactory with a relative deviation of 1.24% with ten experiments at the 0.52 μg 1−1 Cr(VI) level. The effect of various cations, anions and surface active substances (SAS) in synthetic aqueous samples has been investigated.