Donnan Dialysis Matrix Normalization for Cathodic Stripping Voltammetry

Abstract

Previously reported cathodic stripping methods for the determination of phosphate and arsenate which were based upon reversible oxidation of Fe (II) to sparingly soluble salts at an inert electrode were subject to several interferences and were influenced by the sample matrix. In the present study Donnan dialysis was used to transfer the test ions from the sample into a controlled electrolyte. Subsequently, stripping analysis was performed. The resulting determinations were independent of the matrix of the original sample over a wide variety of conditions. Using lake water and wastewater samples, results were obtained which were statistically equivalent to widely accepted analytical procedures for trace level determinations.