SEPARATION AND DETERMINATION OF SCANDIUM BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH DIACETYL-N,N-BIS(4-HYDROXYBENZOYLHYDRAZONE AS A PRECOLUMN CHELATING AGENT

An HPLC method for the determination of scandium(III) was developed, w ith diacetyl-N,N-bis(4-hydroxybenzoylhydrazone (DBHB) as a pre-column chelating agent. Tetradentate DBHB formed a 1:1 chelate with Sc-III io n. The Sc-III-DBHB chelate was separated on a Cla-silica gel column wi th a mobile phase of acetonitrile-water (30 + 70 m/m) containing 5 x 1 0(-3) mol kg(-1) tetramethylammonium bromide and 2.5 x 10(-3) mol kg(- 1) hexamethylenetetramine buffer. Using a 100 mm(3) injection at 420 n m, the detection limit for Sc-III was 8.4 x 10(-10) mel dm(-3) (37 ng l(-1)). Rare earth elements gave no peaks on the chromatogram. The met hod can detected Sc-III in river water without preconcentration.