Spectrophotometric studies on 5- [P-nitrophen-Ylazo] -J-acid and its complexe with trivalent Sc, Y and la ions

An organic dye, 5-[p- nitrophenylazo]-1-hydroxy-6-aminonaphthalene-3-sulfonic acid was prepared, chemically analyzed and subjected to IR spectra. The absorption spectra of this dye was investigated in aqueous solution of varying pH values. The pKp and pKa values were determined from the absorbance wavelength relations at various pH values. The complexes formed between Sc, Y and La and the active ligand were studied spectrophotometrically and by conductimetric titrations. The stability constants of the formed complexes were calculated and the effect of diverse ions was investigated. A spectrophotometric method for the precise determination of the three metal ions was proposed