SPECTROPHOTOMETRIC INVESTIGATION OF 2-(2-PYRIDYLMETHYLENE-AMINO)PHENOL COMPLEXES WITH COBALT(II) AND NICKEL(II) IN METHANOL-WATER SOLUTIONS

The stability constants of Co(II) and Ni(II) complexes with 2-(2-pyrid ylmethyleneamino)phenol (PMAP) have been determined by three methods a t constant temperature theta = (25 +/- 1)-degrees-C, ionic strength l = 0.5 mol dm-3 (NaNO3), in methanol-water medium of volume fraction ph i(methanol) = 10 %, and at different pH in order to optimize the exper imental conditions for using PMAP as a spectrophotometric reagent for Co and Ni determination in beryllium bronzes. PMAP has the main advant ages over other reagents due to the fact that it does not form complex es with Be and that the interferences of Zr can be avoided by pH adjus tment. The influence of the interferences present in Be and Zr bronzes has also been investigated.