Solid phase preconcentration and determination of trace concentrations of total gold (I) and/or (III) in sea and wastewater by ion pairing impregnated polyurethane foam packed column prior flame atomic absorption spectrometry

A low cost solid-phase extraction based protocol for the preconcentration and subsequent determination of gold (I) and (III) in various complex matrices was developed. The method was based upon the use of the ion pairing reagent tetraheptylammonium bromide (THA+.Br−) immobilized polyurethane foams (PUFs) sorbent in packed column for retention of ultra trace concentrations of gold (III) from aqueous chloride medium of pH 3–4 at 5 mL min− 1 flow rate. The retained gold (III) species were recovered (98.5 ± 2.7) by thiourea–HCl at 5 mL min− 1 flow rate. Gold (I) ions after oxidation to gold (III) with Br2 water–HCl were also retained onto the reagent packed PUFs column and recovered (96.5 ± 2.1). A linear plot of gold (III) concentration in the range 0.0–20 ng mL− 1 and a limit of detection of 0.06 ng mL− 1were achieved. The method was applied satisfactorily (> 95%) for the analysis of total inorganic gold (I) and/or gold (III) ions in wastewater samples and anodic slime.

► The method provides a simple and low cost approach for the separation and recovery of gold (I & III) species from complex matrices. ► The reusability of the developed PUFs in packed column was as high as greater than 20 cycles without loss in its performance. ► The capacity data (17 ± 0.7 and 19.5 ± 065 mg g− 1) of the developed sorbent are better than the data (11. 21 ± 1.8 and 5.29 ± 0.9 mg g− 1) (Hayashita et al., 1992). ► The figures of merits of the method confirm the accuracy and precision and the matrix effects were reasonably tolerable. ► The LOD of the method is far below the permissible limit of gold in drinking water.