3-(o-Acetophenyl)-1-methyltriazene-N-oxide. A Reagent for Spectrophotometric Determination of Ni(ll) and Cu(ll) and Evaluation of Stepwise Formation Constants

Jadavpur University, Calcutta-700 082 Manuscript received 4 October 1980, accepted 50 May 1583 Nickel(II) and copper(ll) could be estimated spectrophotometrically with 3-(o-acetophenyl)-1-methyltriazene-N-oxide within pH 6.6-10.4 and 7.0-10.6, respectively. The complexes extracted in chloroform are yellow and have λmax: at 430 nm (NIL,) and 420 nm (CuL2), respectively. The compositions determined by Job's and mole-ratio methods have also been verified from the respective\(\tilde{n}\) values. The Beer's law range, optimum concentration range, molar absorptivity and sensitivity for Ni(II) complex are 0.25-4.5 ppm, 0.5-4 ppm, 1.4 x 104 and 0.0042 µg cm-2 respectively and the same for Co(Il) complex are 0.25-4.7 ppm, 0.8-4.5 ppm, 1.21 x 104 and 0.0053 µg cm-2. The order of stability constants for Cu(II) and Ni(II) complexes, calculated by Leden's and Yatsimirskirs methods agree with Irving-William's rule (Cu > Ni). Either Ion could be estimated In presence of several foreign ions. The analytical precisions in terms of standard deviation are ± 0.26% and ± 0.22 % for nickel estimations and copper estima­tions, respectively