ONLINE PRECONCENTRATION OF SILVER ON A SULFHYDRYL COTTON MICROCOLUMN AND DETERMINATION BY FLOW-INJECTION ATOMIC-ABSORPTION SPECTROMETRY

A rapid and sensitive on-line preconcentration method for the determination of silver in waters by flow injection flame atomic absorption spectrometry is described. Preconcentration is based on the retention of silver on a sulfhydryl cotton fibre microcolumn using a 0.05 mol l(-1) HNO3 carrier solution and subsequent elution with 50 mu l of 0.2 mol l(-1) KCN. The preconcentration factor is 300 (50 mu l elution volume) for a 15 mi sample volume. The detection limit under these conditions is 1 1 mu g l(-1) and the relative standard deviation is 3.5% (10 mu g l(-1)solution, n=5).