Flow Injection Catalytic Kinetic Spectrofluorimetric Determination of Trace Amount of Ruthenium

A novel fluorescence reagent 2-pyridine carboxaldehyde benzoylhydrazone (PCBH) was synthesized. A flow injection (FI) kinetic spectrofluorimetric method was developed for the determination of trace amounts of ruthenium. The method was based on the fluorescence-enhancing reaction of PCBH with potassium bromate, which was catalyzed by Ru3+ in aqueous medium at pH 6.70 and 55 °C. Under these conditions, the oxidized product of PCBH had excitation and emission maxima wavelengths at 284 and 377 nm, respectively. The linear range of this method was 2.0–400 ng ml−1 with a relative standard deviation of 1.8% from a series of 11 standards each containing 50 ng ml−1 of ruthenium. The detection limit was 0.60 ng ml−1 of ruthenium. A high analysis rate of 18 samples per hour was obtained by the FI method. The proposed method was successfully applied to determine ruthenium in synthetic mixtures and mineral samples.