Solid phase selective and extractive preconcentration of silver ion from aqueous samples on modified silica gel with 5-(4-dimethylaminobenzylidene)-rhodanine; prepared by sol-gel method.

A new modified silica gel doped with 5-(4-dimethylaminobenzylidene)-rhodanine was prepared for separation, preconcentration and determination of silver ion by atomic absorption spectrometry. This new modified silica gel was used as an effective adsorbent for the solid phase extraction of Ag(+) from aqueous solutions. The variables that influence the adsorption/desorption of trace levels of Ag(+) were optimized in the column process. The preconcentration factor and capacity of the adsorbent at optimum conditions were found as 220 and 420 microg Ag(+) per gram of adsorbent, respectively. The relative standard deviation and the detection limit for measurement of Ag(+) in our experiments were less than 1.5% (n = 10) and 0.02 microg L(-1), respectively. Common coexisting ions did not interfere with the separation and determination of silver ion. The proposed method was successfully applied for preconcentration and determination of silver ion in some spiked water samples.