Spectrophotometric determination of cobalt(II) with dithizone in the presence of poly(sulfonylpiperidinylmethylene hydroxide)

Abstract

The present work describes a sensitive, selective and rapid method for the determination of cobalt using dithizone in the presence of a water soluble polymer, poly(sulfonylpiperidinylmethylene hydroxide) (PSPMH). The dithizone modified by PSPMH reacts with cobalt(II) in the solutions of pH > 12.0 to produce a blue complex which is soluble in water. The composition of the complex is 1:4:2 mol ratio of Co(II):dithizone:PSPMH. The complex obeys Beer's law from 0.03 to 1.18 mu g mL(-1) with an optimum range. The relative standard deviations have been calculated as 0.2% (10 samples, each containing 0.350 mu g mL(-1) Co(II)). The molar absorptivity is 5.6 x 10(4) L mol(-1) cm(-1). The interference effects of the foreign ions have been examined and it has been determined that only Cu(II) has an interference at the same concentration level as Co(II), which can easily be masked by Gamma.