Cobalt, rhodium and iridium

A highly sensitive and selective spectrophotometric method is proposed for direct trace determination of Fe(III), Cu(II) and UO2(II) in aqueous solutions. The method is based on the reaction of those cations with a new analytical reagent 2-ethanolimino-2-pentylidino-4-one (B3). Under the optimum reaction conditions and other important analytic parameters, B3 reacts with the investigated cations and forms colored complexes. The optimum pH for complex formation has been adjusted. The color reaction is rapidly completed and the absorbance remains stable for at least a week at room temperature. The Fe(III) complex is detected at λmax = 440 nm and pH = 3.5, the Cu(II) complex is detected at λmax = 340 nm and pH = 6.0, while that of UO2(II) is detected at λmax = 370 nm and pH = 4.0. BearLambert’s law is obeyed in the concentration range = 0.5 ‐ 3.0·10 ‐4 M (2 ‐ 17 μg/ml for Fe(III), 3 ‐ 9 μg/ml for Cu(II) and 13 ‐ 81 μg/ml for UO2(II) complexes. The stoichiometries of the formed complexes are determined using different spectrophotometric methods. The conditions for the complexation were determined. The rate of the reaction between Fe(III) ion and the ligand has been evaluated under pseudo first order condition. The ability of the present ligand to determine micrograms of Fe(III), Cu(II) and UO2(II) ions is tested and the resulted data are analyzed using statistical parameter to obtain the minimum error. The effect of various substances on the determination of the investigated cations is also investigated in detail. The results indicate that most of the studied co-existing substances could be tolerated in considerable amounts. The proposed method offers the advantages of sensitivity, rapidity, selectivity and simplicity without any prior separation or extraction. It has been applied to the analytic samples with satisfactory results.

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SPECTROPHOTOMETRIC DETERMINATION OF Fe(III), Cu(II) AND UO2(II) IONS BY A NEW ANALYTICAL REAGENT DERIVED FROM CONDENSATION OF MONOETHANOLAMINE AND ACETYL ACETONE

F.H. Jumean

Papers

Kinetic studies of the reaction between dihalodicarbonylrhodate(I) anions and 2-aminopyridine