QUALITATIVE, SEMIQUANTITATIVE AND SPECTROPHOTOMETRIC DETERMINATION OF RUTHENIUM(III) BY SOLID-PHASE EXTRACTION WITH 3-HYDROXY-2-METHYL-1,4-NAPHTHOQUINONE-4-OXIME-LOADED POLYURETHANE FOAM COLUMNS

A sensitive and selective extraction method was developed for the detection, semi-quantitative and spectrophotomeric determination of ruthenium(III) in aqueous media. The method is based on the sorption of the ruthenium(III) complex of 3-hydroxy-2-methyl-1,4-naphthoquinone-4-oxime on a porous polyurethane foam membrane. In batch experiments, it was possible to detect as low as 0.1 and 0.02 ppm of ruthenium(III) with unloaded foam and foam loaded with reagent, respectively. The method was also employed for the detection of 10 ppb of ruthenium using the reagent foam column mode. The selectivity of the method for the detection of 1 ppm of ruthenium(III) in the presence of high concentrations of diverse ions was achieved. Preconcentration of ruthenium(III) from large sample volumes was carried out on a loaded foam column at pH 5-7, eluted with acetone and determined spectrophotometrically at 450 nm. The sorbed complex species on the foam showed an absorption maximum at 460 nm with a molar absorptivity of 2.8 x 10(4) dm(3) mol(-1) cm(-1). On this basis, a method for the direct spectrophotometric determination of ruthenium(III) based on liquid-solid extraction of the Ru(III)reagent complex on thin-layer parallelepiped foam was developed. The proposed methods were applied for the determination of ruthenium(III) in water and in its complexes.