Quantification of sub-nanomolar levels of aluminum by adsorptive stripping voltammetry using rubeanic acid as a selective chelating agent

Abstract

A novel, sensitive and selective adsorptive stripping procedure for determination of aluminum is presented. The method is based on the adsorptive accumulation of dithiooxamide (Rubeanic acid) complex of aluminum onto a hanging mercury drop electrode, followed by reduction of adsorbed species by voltammetric scan using differential pulse modulation. The influences of control variables on the sensitivity of the proposed method for the determination of aluminum were studied. The optimum analytical conditions were found to be Rubeanic acid (RA) concentration of 8.0×10-5 M, ammonia buffer (NH3-NH4Cl) pH of 6.5, and accumulation potential at -50 mV vs. Ag/ AgCl with an accumulation time of 60 s. The peak currents are proportional to the concentration of aluminum over the 0.3-70 ngmL-1 ranges with detection limit of 0.012 ngmL-1. The procedure was applied to the determination of aluminum in the Lab. Water, HCl of Merck and potato samples with satisfactory results. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.