Adsorptive Stripping Voltammetric Determination of Antimony by Using Alizarin Red S

A sensitive and selective voltammetric method for determination of antimony(III) using Alizarin Red S (ARS) as complexing agent is described. The method is based on the monitoring the oxidation peak of antimony(III)-ARS complex at -520mV in ammonium-ammonia buffer (pH=7.5). The peak current was measured by scanning the potential from -700mV versus Ag/AgClto more positive potentials without accumulation in the presence of 110-6molL-1 of ARS. The limit of detection (3s) and limit of quantification (10s) of the method were calculated from calibration curve as 1.45gL- and 4.8gL- respectively. The calibration plot for antimony(III) was linear in the range of 4.8-30gL-. The interference of various ions was examined. Serious interference from Al(III), Fe(III), Cu(II), Pb(II), and Zn(II) was eliminated by addition of EDTA to the solution. The method was applied to drinking water samples. The recoveries were in the range 94%-105%. The results obtained from the developed method were compared with those from the differential-pulse anodic-stripping method and no statistically significant difference was found.