Preconcentration of trace amounts of cadmium in aqueous samples on minicolumns packed with Chromosorb series gas chromatographic stationary phases and its determination by electrothermal atomic absorption spectrometry

Abstract

The adsorption characteristics of five commercially available Chromosorb GC stationary phases towards Cd²⁺ and their application to the preconcentration and ETAAS determination of Cd²⁺ in several water samples were studied. The experimental results indicated that although all of the five Chromosorb GC stationary phases studied can retain Cd²⁺ quantitatively from aqueous solutions at appropriate pH values without adding chelating reagent, Chromosorb 105 displayed the highest adsorption capacity. A highly sensitive, simple methodology for preconcentration and ETAAS determination of trace amounts of cadmium in natural water samples using a Chromosorb 105 packed minicolumn is proposed. Conditions for quantitative and reproducible preconcentration, elution and subsequent ETAAS determination were established. The high retention efficiency (>95%) for Cd²⁺ provides a sensitivity enhancement of 100-fold for a 200 mL sample volume with a detection limit of 6.2 ng L⁻¹ (3σ).