Simultaneous square wave, stripping voltammetric determination of platinum group metals (PGMs) and lead at trace and ultratrace concentration level - Application to surface water

The present work purposes two goals: to set up both a new method for simultaneously determining, at ultratrace level concentrations, Pd(H) and Rh(III) by square wave adsorption stripping voltammetry (SWAdSV), using dimethylglyoxime (DMG) as complexing agent, and a new analytical procedure for the sequential determination of Pt(II), Rh(III), Pd(II) by square wave adsorption stripping voltammetry (SWAdSV) and Pb(II) by square wave anodic stripping voltammetry (SWASV) in surface water. The critical comparison between peak area and peak current highlights once more that lower limits of detection are obtained if peak area is employed as instrumental datum. About 0.5 mol/L acetate buffer pH 3.5 + 1.8 x 10(4) mol/L dimethylglyoxime (DMG), 0.3 mol/L HCl and 0.6 mmol/L formaldehyde + 1.2 mmol/L hydrazine (formazone complex) in 0.3 mol/L HCl were employed as the supporting electrolytes. The analytical procedure was verified by the analysis of the standard reference materials: sea water BCR-CRM 403 and fresh water NIST-SRM 1643d. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were generally lower than 6% in all cases. Once set up on the standard reference materials, the analytical procedure was transferred and applied to surface water sampled in proximity to superhighway and in the Po river mouth area. A critical comparison with spectroscopic measurements is also disc used. (c) 2005 Elsevier B.V. All rights reserved.