ONLINE PRECONCENTRATION OF SILVER ON ACTIVATED ALUMINA AND DETERMINATION IN BOREHOLE WATER BY FLOW-INJECTION ATOMIC-ABSORPTION SPECTROPHOTOMETRY

A micro column of activated alumina in the basic form was used in conjunction with flame atomic absorption for the preconcentration and determination of silver in borehole water. The silver was accumulated on the alumina column by pumping sample solution at pH 4 through the column at a rate of 5 cm3 min-1 for 5 min. By incorporating an injection valve and a simple interfacing device into the system, silver was determined by elution into the nebulizer of an atomic absorption spectrophotometer with 500 μl of 2 mol l-1 nitric acid. Regeneration of the alumina to its basic form was achieved by 0.15 mol l-1 ammonia solution pumped through the column at 5 ml min-1 for 2 min. A detection limit of 4 μg l-1 was measured, based on a sample volume of 25 ml. The relative standard deviation was less than ±5% at concentration levels above 10 μg l-1. © 1990 Springer-Verlag.