Terminology and Convention for Electrochemical Stripping Analysis

Abstract

Introduction: The term electrochemical stripping analysis is applied to a family of procedures involving a preconcentration of the determinand (or a salt or derivative of the determinand) onto the working electrode, prior to its direct or indirect determination by means of an electroanalytical technique1,2. Such a combination of an effective accumulation step with an advanced measurement procedure results in a very low detection limit, and makes stripping analysis one of the most important techniques in trace analysis. The original stripping analysis method involved the cathodic electrodeposition of amalgam-forming metals onto a hanging mercury drop (working) electrode, followed by the anodic voltammetric determination of the accumulated metal during a positive-going potential scan3. Numerous advances during the 1980s and 1990s, however, have led to the development of alternative preconcentration schemes and advanced measurement procedures that further enhance the scope and power of stripping analysis4,5. As a consequence, numerous variants of stripping analysis exist currently, differing in their method of accumulation and measurement. A recent text on stripping analysis is by Brainina and Neyman,6 and recent reviews on adsorptive stripping voltammetry are by Kalvoda and Kopanica,7 van den Berg,8 and Paneli and Voulgaropoulos.9Problems in selecting an effective nomenclature for stripping analysis are discussed in this document. Stripping analysis incorporates a two step process - accumulation and determination - and the technique can be considered to be a 'hyphenated technique'. The method of determination has been included, usually, in naming a particular technique, but often the method of accumulation has not. In some cases, eg. adsorptive stripping voltammetry, the method of accumulation is given but no indication is given as to whether the determination is cathodic or anodic (or whether it measures a capacitance current due to desorption).The purpose of this document is to recommend classification, and relevant terminology, for the different procedures used in electrochemical stripping analysis.