Simultaneous Derivative Spectrophotometric Determination of Co(II), Cu(II) and Fe(II)

Abstract

A simple, sensitive and rapid derivative spectrophotometric method using di-2-pyridylketone thiosemicarbazone (DPKT) has been devoloped for the simultaneous determination of Co(II), Cu(II) and Fe(II) ions. Complex formation was completed for three metals in Et0H-H 2 0 (1/9) containing 0. 1 Μ pH:6 acetate buffer within 5 min at room temperature and the chelates were stable for at least 2 days. Using zero-crossing first and second order derivative spectrophotometry, three metals were determined without any separation and background correction techniques. First derivative absorbance values ('D) at 489. 0 nm (zero-crossing wavelength of Fe(II) and Cu(Il)) and 649. 4nm (zero-crossing wavelengt of Co(II) and Cu(ll)) were proportional to Co(II) and Fe(II) concentrations respectively. Second derivative absorbance value ( : D) at 406. 2 nm(zero-crossing wavelength of Co(II) and Fe(II) )was proportional to Cu(II) concentration. Linear correlations between derivative absorbance values and metal concentrations over the ranges of 1 -5 ppm for Co(II) (r:0. 9996) and Cu(II) (r:0. 9995) and 1-3 ppm for Fe(II)(r:0. 9998) were obtained. A systematic study was made for the investigation of the effect of the presence of diverse ions on the determination.