Voltammetric determination of aluminum-Alizarin S complex by renewable silver amalgam electrode in river and waste waters

Abstract

The direct voltammetric determination of aluminum is difficult because it is reduced at very low potential −1.75V versus Ag/AgCl. Therefore, in this work a simple and rapid stripping voltammetry method of Alizarin S-Al complex determination on renewable silver amalgam film electrode was proposed. The electrode process in complex electrolyte is irreversible and controlled by the surface phenomena. Experimental conditions such as preconcentration time and operation parameters were optimized. The promising results were obtained in 0.1M ammonia buffer, 0.01M KBrO3, 0.25μM Ca, 0.1μM EDTA. The calibration graph was linear from 5 to 45μgL−1 with sensitivity of 14.6μA/mgL−1, detection limit of 0.2μgL−1 and repeatability below 3.5%. With accumulation time of 4s the sensitivity increases to 17.4μA/mgL−1 with r=0.9978 but the range of linearity was limited to 20μgL−1. The problem of the main interferent which is zinc was resolved by the EDTA addition. Procedure was verified using waste waters CRMs with recovery 99–110% and spiked Vistula River water.