SPECTROPHOTOMETRIC STUDY OF COPROPORPHYRIN-I COMPLEXES OF COPPER(II) AND COBALT(II)

The reagent ramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) was used for the spectrophotometric determinat ion of copper(II) and cobalt(II) in the presence of pyridine and imida zole catalysts. Optimum conditions were investigated and the methods w ere applied to the determination of parts per billion levels of copper (II) and cobalt(II). The Sandell sensitivities of the recommended proc edures were 0.568 mu m cm(-2) and 0.464 mu g cm(-2) (for A = 0.001) fo r copper and cobalt, respectively, The relative standard deviations Ev ert 2.0% for copper and 1.0% for cobalt. The kinetics of the reaction of CPI with copper(II) and cobalt(II) in the presence of the catalysts and the influence of the temperature were studied, and their kinetic constants determined. The influence of light on the photodecomposition of CPI was also studied.