SYNTHESIS AND EFFICIENCY OF 5-(2-HYDROXYPHENYLAZO)-INDAZOLES AS NEW REAGENTS FOR THE DETERMINATION OF VANADIUM

Four ate compounds based on 5-aminoindazole have been synthesized and characterized by elemental analysis as well as different spectroscopic techniques. The potentiality of the prepared compounds as new chromop horic reagents for the spectrophotometric determination of VO2+ was st udied by extensive investigation of optimum conditions favouring the f ormation of the coloured complexes. The effect of interfering ions on the determination of VO2+ was investigated. Beer's law is obeyed in th e concentration range of 1.0-12 mu g/ml. The detection limits are 0.8, 0.9, 0.7, and 1.1 mu g/ml using reagent 1a, 1b, 1c, and 1d, respectiv ely. The standard deviations of the proposed method are 0.098, 0.111, 0.089, and 0.078. The molar absorptivities are 5.8, 6.7, 6.1, and 8.2 x 10(3) l . mol(-1). cm(-1) for 1a-d, respectively, whereas Sandell se nsitivities are found to be 0.0187, 0.0163, 0.0174, and 0.0146 mu g . cm(-2) using the same reagents. The ability of using these reagents as metallochromic reagents in complex on III titrations was also studied .