The polarographic study of Cobalt(II)-dithiocarbamate complexes at DME

Abstract

Cobalt is a naturally occurring element in the earth’s crust. It is a very small part of our environment and very small amounts are needed for many animals and humans to stay healthy. Cobalt poisoning can occur when exposed to large amounts of cobalt. The aim of this study was to develop a facile, rapid, robust, sensitive and selective methodology for the determination of cobalt(II). Two new ligands, ammonium 2,6-dimethyl morpholine dithiocarbamate (ADMM-DTC) and ammonium 3-methyl piperdine dithiocarbamate (AMP-DTC) were synthesized in the laboratory. The method was based on chelation of cobalt(II) with ADMM-DTC/AMP-DTC in presence of NH4OH at pH 7.2 and 8.2 to produce catalytic hydrogen currents at -1.28 V and -1.38 V vs SCE respectively and prior detected by D.C polarography. Optimized polarogaphic conditions were established by studying effect of pH, supporting electrolyte (NH4Cl), ligand & metal ion concentrations and effect of adverse ions on peak height to improve the sensitivity, selectivity and detection limits of the present method. This technique is successfully applied for the analysis of cobalt(II) in different matrices with recoveries ranging from 93- 98 % and the results obtained were comparable with the differential pulse polarography (DPP).