Different Behavior of Organotin Compounds by Anodic Stripping Voltammetry and their Quantification after Partial Ion Exchange Separation

Abstract.

 The electrochemical behavior and the analytical performance of the organotin compounds mono-, di- and tributyltin, as well as, mono-, di- and triphenyltin were investigated by various voltammetric techniques, such as alternating current polarography of the first harmonic (ACP1), square wave polarography at a hanging mercury drop electrode (SQW) and anodic stripping voltammetry (ASV). Differences could be observed in the sensitivity, the detection limit and the reproducibility of the organotins by the techniques used and in some cases their simultaneously determination was difficult, as the half-wave potentials were very close together. However, by ASV double peaks were observed only for the monophenyltin and dibutyltin species, distinguishing them from the overlapping peaks of diphenyltin and triphenyltin, respectively. This different electrochemical behavior, is due to the formation of intermediate products during the electrolysis of these compounds with other half wave potentials and was successfully utilized for the separation and determination of monophenyltin in the presence of diphenyltin. In the case of dibutyltin, where no linear calibration curves for the two peaks were obtained, a prior suitable ion exchange procedure was developed for its separation and determination from the interfering triphenyltin. The successful application of this technique could be proved on a CRM freshwater sediment of BCR.