Trace enrichment and determination of silver by immobilized DDTC microcolumn and flow injection atomic absorption spectrometry

Flow injection (FI) system incorporating a microcolumn of immobilized diethyldithiocarbarnate (DDTC) on surfactant-coated alumina was combined with atomic absorption spectrometry for on-line trace enrichment and determination of silver in different matrices. Silver was deposited on the microcolumn by processing a standard or solution of analyte at pH 3-4 on the column. Injection of 250 RI of ethanol then served to elute the retained species to atomic absorption spectrometry (AAS). A sample volume of 20 ml resulted in a pre-concentration factor of 125, and precision at the 20 mug l(-1) was 4% (R.S.D.). The procedure was applied to tap water, well water, rain water, sea water, radiology film, and lead concentrate samples. The accuracy was assessed through recovery experiments, independent analysis by furnace-AAS, and analysis of certified reference material. (C) 2004 Elsevier B.V. All rights reserved.