Determination of iron(III), cobalt(II) and chromium(III) in various water samples by flame atomic absorption spectrometry after preconcentration by means of Saccharomyces carlsbergensis immobilized on amberlite XAD-4

A method for the determination of Fe(III), Co(II) and Cr(III) by flame atomic absorption spectrophotometry (FAAS) after preconcentrating on a column containing S. carlsbergensis immobilized on Amberlite XAD-4 has been developed. The optimum values of pH, amount of adsorbent, elution solution and flow rate of the sample solution were determined for the quantitative recovery of the analytes. The effect of interfering ions on the recovery of the analytes was also investigated. Under the optimum conditions, recoveries of Fe( III), Co( II) and Cr( III) by S. carlsbergensis immobilized on Amberlite XAD-4 were 99 +/- 2, 100 +/- 2 and 98 +/- 2% at 95% confidence level, respectively. The limit of detections for Fe( III), Co( II) and Cr(III) were 2.8, 3.9 and 7.4 ng mL(-1), respectively. The proposed method was applied to the determination of the analytes in various water samples. The validity of the method was checked with spiked water samples. Fe( III), Co( II) and Cr( III) was determined with a relative error of less than 5%.