PLATINUM GROUP AND TRAFFIC-RELATED TOXIC METALS. THEIR SIMULTANEOUS VOLTAMMETRIC DETERMINATION IN MARINE FILTERING ORGANISMS, POSSIBLE POLLUTION BIO-MONITORS

The present paper reports a new electroanalytical procedure for the simultaneous voltammetric determination of ultra-trace platinum(II), palladium(II), rhodium(III), copper(II), lead(II), cadmium(II) and zinc(II) by square wave adsorptive catalytic stripping voltammetry (SWAdCSV) in mussels and clams, possible bio-monitors, using a conventional three-electrodes voltammetric cell: a stationary hanging mercury drop electrode (HMDE) as working electrode and a platinum electrode and an AgAgClKClsat electrode as auxiliary and reference electrodes, respectively 0.1 mol L-1 HCl + 2.3x10-4 mol L-1 dimethylglyoxime (DMG) + formazone complex [0.7 mmol L-1 formaldehyde + 1.5 mmol L-1 hydrazine in 0.1 mol L-1 HCl] + 8.5 x10-2 mol L-1 NaBrO3 + 4.9x10-4 mol L-1 EDTA-Na2 was employed as the supporting electrolyte. The analytical procedure was verified by the analysis of the standard reference materials Mussel Tissue BCR-CRM 278 and Oyster Tissue NIST-SRM 1566a. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were generally lower than 7 % in all cases. Once set up on the standard reference materials, the analytical procedure was transferred and applied to mussels and clams sampled in the Po river mouth area. A critical comparison with spectroscopic measurements is also discussed.