USE OF CALIXARENES AS MODIFIERS OF CARBON-PASTE ELECTRODES FOR VOLTAMMETRIC ANALYSIS

The use of calixarene-based chemically modified carbon paste electrodes (CMCPEs) in voltammetric analysis is reported here. A polymeric calixarene I was incorporated successfully and used for the accumulation of lead(II), copper(II), and mercury(II) ions with subsequent anodic stripping voltammetry as the determination step. The electrode response depended on the calixarene content, the electrolyte, and the preconcentration time and analyte concentration, as well as the constituents of the sample matrix. The presence of alkali metal ions in the sample solution was found to have an adverse effect on electrode response, due to the preferable binding of these ions by the calixarene units immobilized in the carbon paste. Attempts to overcome this interference employed a nonpolymeric sulfur-containing calixarene, the thioamide II, in the electrode. The stripping current R;as not enhanced by introduction of this compound as an electrode modifier, perhaps due to adsorption of the calixarene on the carbon particles via its metal ion binding site. However, the application of calixarenes to voltammetric methods of analysis is demonstrated and provides an additional use of calixarenes in electroanalysis.