Precipitation-dissolution system for silver preconcentration and determination by flow injection flame atomic absorption spectrometry

In this paper, flame atomic absorption spectrometry was used for the determination of silver in various materials. The proposed preconcentration method is based on the continuous precipitation of silver as p-dimethylaminobenzilidene-rhodanine (PDBR) complex and dissolution of the precipitate with potassium cyanide. EDTA was added to the sample solution to mask large concentrations of Fe(III), Ni(II), Cu(II), Zn(II), Pb(II), Co(II) and Al(III). An enhancement factor of 20 was obtained for a preconcentration time of 3 min, resulting in a sampling frequency of 16 h(-1). The detection limit (3sigma) in the sample solution was 5 ng ml(-1). The relative standard deviation at 30 ng ml(-1) level was 4.7%. Analytical results obtained for alloy, biological reference material and ore samples analyzed were in good agreement with the certified values and comparable to those obtained with other techniques. (C) 2002 Elsevier Science B.V. All rights reserved.