Determination of iron, cobalt and nickel as chelates with 4-(2-thiazolylazo)resorcinol by reversed-phase high-performance liquid chromatography

Abstract

The chelates of iron, cobalt and nickel with 4-(2-thiazolylazo)resorcinol were separated on a column (250 × 4.6 mm i.d.) of Zorbax ODS (6 µm) with a mobile phase (0.75 ml min^–1) of methanol–water (40 + 60, v/v) containing 0.01 mol dm^–3 KH₂PO₄—Na₂HPO₄ buffer (pH 7.0) and were detected at 580 nm. The calibration graphs were rectilinear from 0.1 to 5 ppm for both cobalt and nickel, and from 1 to 5 ppm for iron. The detection limits were 2.0, 0.2 and 0.6 ng for iron, cobalt and nickel, respectively. The method has been applied to the analysis of real samples.