Kaoru Sakai

High-performance liquid chromatography of copper, cobalt, nickel, chromium and vanadium chelates with 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-sulphopropylamino)-phenol

The reversed-phase liquid chromatography of several metal chelates with 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-sulphopropylamino)phenol (5-Br-PAPS) on a C18-bonded stationary phase using methanol—water as the mobile phase was investigated. The retention of the chelates on the central metal ions, the methanol—water ratio and the concentration of salt in the mobile phase. The chelates of Cu(II), Co(II), Ni(II), Cr(III) and V(V) at parts per billion levels were separated in about 15 min using a LiChrosorb RP-18 column (125 mm × 4 mm I.D.) with methanol—water (65:35) as the mobile phase containing 10−4M 5-Br-PAPS, 0.1 M lithium chloride and 0.01 M acetate buffer (pH 4).