ION-PAIR REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SEPARATION AND DETERMINATION OF RUTHENIUM, RHODIUM, COBALT AND COPPER AS CHELATES WITH 1-(2-PYRIDYLAZO)-2-NAPHTHOL-6-SULFONIC ACID

Ruthenium(III), rhodium(III), cobalt(II) and copper(II) a chelates wit h 1-(2-pyridylazo)-2-naphthol-6-sulfonic acid (PAN-6S) were separated by ion-pair reversed-phase high-performance liquid chromatography and detected spectrophotometrically at 580 nm. The optimum conditions for the separation and determination of the Ru(III)-, Rh(III)-, Co(II)- an d Cu(II)-PAN-6S chelates were investigated. The chelates were separate d on a Nucleosil C-18 column (250x4.6 mm I.D.) using acetonitrile-wate r (30:70, v/v) containing 0.01 M acetic acid-sodium acetate buffer (pH 5.0) and 0.01 M tetrabutylammonium bromide (TBABr) as a mobile phase at a flow-rate of 1.0 ml min(-1). The detection limits were 2.6 ng for Ru, 1 ng for Rh and 0.3 ng for both Co and Cu. (C) 1997 Elsevier Scie nce B.V.