Determination of iron in water samples by adsorptive stripping voltammetry with a bismuth film electrode in the presence of 1-(2-piridylazo)-2-naphthol

An adsorptive stripping voltammetry method for the determination of iron has been developed. The procedure is based on the adsorptive collection of a complex of iron with 1-(2-piridylazo)-2- naphthol (PAN) on a bismuth-coated glassy carbon electrode (BiFE). Factors affecting the stripping performance, such as pH, PAN concentration (C-PAN), potential, accumulation time (E-ads, t(ads)), and interference by other ions were also studied. The optimum conditions were obtained in a 0.1 mol L-1 acetate buffer at pH 4.0, CPAN 5.0 mu mol L-1, t(ads) 60 s, E-ads -400 mV, pulse height 4.0 mV, pulse amplitude 25 mV, and frequency 15 Hz. The detection limit was found to be 0.1 mu g L-1 when a t(ads) of 60 s was used, and the linear range was from 0.4 to 60.0 mu g L-1. The proposed procedure was validated by determining of Fe(III) in CRM-MFD, QCS-19 and CRM-SW certified reference materials and applied in seawater samples with satisfactory results. (c) 2008 Elsevier B.V. All rights reserved.