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

The use of calixarene-based chemically modified carbon paste electrode s (CMCPEs) in voltammetric analysis is reported here. A polymeric cali xarene I was incorporated successfully and used for the accumulation o f lead(II), copper(II), and mercury(II) ions with subsequent anodic st ripping voltammetry as the determination step. The electrode response depended on the calixarene content, the electrolyte, and the preconcen tration time and analyte concentration, as well as the constituents of the sample matrix. The presence of alkali metal ions in the sample so lution was found to have an adverse effect on electrode response, due to the preferable binding of these ions by the calixarene units immobi lized in the carbon paste. Attempts to overcome this interference empl oyed a nonpolymeric sulfur-containing calixarene, the thioamide II, in the electrode. The stripping current R;as not enhanced by introductio n of this compound as an electrode modifier, perhaps due to adsorption of the calixarene on the carbon particles via its metal ion binding s ite. However, the application of calixarenes to voltammetric methods o f analysis is demonstrated and provides an additional use of calixaren es in electroanalysis.