Separation and determination of scandium by reversed-phase high-performance liquid chromatography with diacetyl-N,N-bis(4-hydroxybenzoylhydrazone) as a pre-column chelating agent

Abstract

An HPLC method for the determination of scandium(III) was developed, with diacetyl-N,N-bis(4-hydroxybenzoylhydrazone) (DBHB) as a pre-column chelating agent. Tetradentate DBHB formed a 1:1 chelate with Sc^III ion. The Sc^III–DBHB chelate was separated on a C₁₈–silica gel column with a mobile phase of acetonitrile–water (30 + 70 m/m) containing 5 × 10^–3 mol kg^–1 tetramethylammonium bromide and 2.5 × 10^–3 mol kg^–1 hexamethylenetetramine buffer. Using a 100 mm³ injection at 420 nm, the detection limit for Sc^III was 8.4 × 10^–10 mol dm^–3 (37 ng l^–1). Rare earth elements gave no peaks on the chromatogram. The method can detected Sc^III in river water without preconcentration.