Cytosine-functionalized polyurethane foam and its use as a sorbent for the determination of gold in geological samples

Abstract

A solid phase extraction procedure was developed for the separation and preconcentration of trace amounts of Au(III) in geological samples by using a polyurethane foam column modified with cytosine. The influence of the flow rate of the sample solution, the pH effect, eluent type, sorption capacity, and presence of matrix ions on the solid phase extraction procedure was investigated. The analytical results for international gold reference materials measured by this new method were in close agreement with those obtained by other well-established methods and values. Under the optimum conditions, the detection limit (3σ, n = 6) for the analyte was 6 ng L⁻¹, with an enrichment factor of 480. The equilibrium data were best represented by the Langmuir isotherm model, showing pseudo-first-order kinetics. The maximum adsorption capacity of Au(III) on the adsorbent was 98.9 mg g⁻¹.