Preconcentration of trace indium in aqueous samples using sodium dodecyl sulphate/activated carbon prior to electrothermal furnace absorption spectrometry

Abstract

ABSTRACT In this study, activated carbon (AC) modified by sodium dodecyl sulphate (SDS), written as SDS/AC, has been proposed for preconcentration and determination of indium from aqueous solutions in a solid phase extraction technique. AC was put on the membrane filter in the column, and SDS was added into sample solutions. Subsequently, with the SDS modification on AC, the preconcentration of indium onto the adsorbent was simultaneously performed in the flow system as solid-phase extraction. After the preconcentration step, indium retained on SDS/AC was eluted with 1 mol L−1 HNO3, and the indium concentration in collected eluent was determined by electrothermal atomic absorption spectrometry (ETAAS). Some important analytical parameters, such as the conditions of adsorbent, sample solution, eluent and interfering elements, were investigated and optimised for the quantitative determination of trace indium. In the case of sample solution of 200 mL at 1 μg L−1 indium, the enrichment factor and the relative standard deviation (n= 5) were 363% and 3.8%, respectively. The detection limits (3S/N) were calculated to be 0.2 ng L−1. This developed procedure was successfully applied into the separation and determination of trace amount of indium from environmental samples.