Tutorial review. Voltammetric determination of trace metals and organics after accumulation at modified electrodes

Abstract

The applications of chemically modified electrodes (CMEs) to the determination of trace amounts of metals and organic analytes are discussed. The common feature of the CMEs reviewed is that prior to the voltammetric determination step the analyte is collected or accumulated onto the electrode. The accumulation step serves to preconcentrate the analytes from dilute solution, making their determination easier. It is analogous to the preconcentration step employed in stripping voltammetry at conventional electrodes. Trace analytes can be accumulated in several ways: ion-exchange, complexation, bioaccumulation, covalent attachment, and hydrophobic interaction accumulation schemes are discussed. Uses of CMEs in speciation analysis are outlined, and modified mercury-film electrodes and mercury films based on CMEs are discussed. Examples of the use of CMEs in the determination of trace metals [e.g., copper(II), lead(II), mercury(II), and silver(I) ions] and organic compounds are given.