Reversed-phase ion-pair partition chromatography of iron, cobalt and nickel chelates with 4-hydroxy-3-(2-pyridylazo)naphthalene-1-sulphonic acid

Abstract

The reversed-phase ion-pair partition chromatography of 4-hydroxy-3-(2-pyridylazo0naphthalene-1-sulphonic acid (α-PAN-4S) and its metal chelates was studied. Cobalt(III), iron(I) and nickel(II) chelates and excess of α-PAN-4S were separated on the column and eluted with acetonitrile—water (37–:60–63, v/v) containing 0.025 M tetrabuylammonium bromide, 0.005 M 3-(N-morpholino)propanesulphonic acid—sodium hydroxide buffer (pH 7) and 10 −4 M Na 2(EDTA). Cobalt, iron and nickel were simultaneously determined without interferences from other metals. The effects of the elunt composition and pH on the retention of all species were examined. The method was applied to the determination of cobalt, iron and nickel in a glass sample.