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

Potentiometric microdetermination of phosphate, arsenate and sulfide

For mercuri-gravi-potentiometric microdetermination of phosphate, arsenate and sulfide, optimum conditions have been investigated for their precipitation with cations of Th [IV], Fe [III] and Hg [II] respectively. Excess EDTA was then added to react with unreacted cation and the remaining EDTA was finally back titrated with Hg [II] using silver amalgam and SCE combination. For microdetermination of these anions, the standard deviation, coefficient of variation, and percentage recovery were calculated indicating the high accuracy and reliability of the applied procedures. There is a significant correlation between suggested and standard procedures which confirmed by F and t tests