Directly silica bonded analytical reagents: synthesis of 2-mercaptobenzothiazole–silica gel and its application as a new sorbent for preconcentration and determination of silver ion using solid-phase extraction method

A new and efficient method is described for the easy synthesis of directly bonded 2-mercaptobenzothiazole–silica gel. This new bonded analytical reagent is used as an effective sorbent for the solid-phase extraction of silver ion from aqueous solutions. Conditions for effective adsorption of trace levels of silver ion concentration are optimized with respect to different experimental parameters in column process. Sodium thiosulfate solution could efficiently elute the adsorbed silver ion from the surface of the sorbent which then was determined by atomic absorption spectroscopy (AAS). Common coexisting ions did not interfere with the separation and determination. The preconcentration factor is 300 (1 ml elution volume) for a 300 ml sample volume. The sorbent exhibited excellent stability and its sorption capacity under optimum conditions has been found to be 343 μg of silver per gram of sorbent. The relative standard deviation under optimum conditions is 2.04% (n=7). Accuracy of the method was estimated by using test samples of natural water spiked with different amounts of silver ion. The method is simple and inexpensive.