Online trace enrichment and determination of cobalt ion as an anionic complex by flow injection atomic absorption spectrometry

A flow injection system incorporating a microcolumn of activated alumina was combined with atomic absorption spectrometry for on-line trace enrichment and determination of cobalt in waters and vitamin B-12. Deposition of cobalt as its cyano complex was effected with the use of an acidic alumina microcolumn, and injection of ammonia solution (500 mu l, 2 M) served to elute species retained on the atomic absorption spectrometer. A sample volume of 15 ml resulted in a preconcentration factor of 120, and precision at the 500 and 50 mu g liter(-1) levels was +/- 3.1 and +/- 3.3% (RSD), respectively. The procedure was applied to mineral water, spring water, river water, and vitamin B-12 and accuracy was assessed through a recovery experiment. (C) 1999 Academic Press.