Catalytic-adsorptive stripping voltammetric determination of ultra-trace iridium(III). Application to fresh- and sea-water

An extremely sensitive stripping voltammetric procedure for ultra-trace determination of iridium(III) is reported. The method is based on the interfacial accumulation of the iridium(III)–CTAB complex onto the glassy carbon electrode, followed by the catalytic reduction of the adsorbed complex in the presence of bromate. 0.3 mol L−1 acetate buffer pH 4.7 + 6.9 × 10−2 mol L−1 NaBrO3 + 2.7 × 10−5 mol L−1 cetyltrimethylammonium bromide (CTAB) + 0.2 mol L−1 KCl was employed as the supporting electrolyte. alytical procedure was verified by the analysis of the standard reference materials: Sea Water BCR-CRM 403 and Fresh Water NIST-SRM 1643d. curacy, expressed as relative error e%, was satisfactory, being lower than 6%, while precision as repeatability, expressed as relative standard deviation sr%, was generally lower than 5%. The limit of detection was of the order of 2–3 ng L−1. et up on the standard reference materials, the analytical procedure was transferred and applied to superficial water sampled in proximity to superhighway and in the Po river mouth area.