Preconcentration of cobalt with 8-hydroxyquinoline and gas chromatographic stationary phase Chromosorb 105 and its determination by graphite furnace atomic absorption spectrometry.

This paper presents a study of the adsorption characteristics of a commercially available GC stationary phase Chromosorb 105 for Co(2+), which can be successfully applied to the preconcentration of Co(2+) in water samples followed by GFAAS determination. After reacting with 8-hydroxyquinoline to form a complex at pH 8.0, Co(2+) in water can be retained on a minicolumn packed with Chromosorb 105 and eluted with 2.5 ml of a mixture of ethanol and 2 moll(-1) HNO(3) (2+1, v/v). The recoveries of Co(2+) from 200 ml of tap water, river water and bottled natural mineral water samples are quantitative. Conditions for quantitative and reproducible preconcentration, elution and subsequent GFAAS determination were studied. A highly sensitive, simple method for preconcentration and GFAAS determination of trace amount of cobalt in natural water samples using a Chromosorb 105 packed minicolumn has been proposed. The high retention efficiency ( approximately 95%) for Co(2+) provides a sensitivity enhancement of 80 for a 200 ml sample volume with a detection limit of 13.4 ngl(-1) (3sigma) and a quantification limit of 44.5 ngl(-1) (10sigma).