A simple and sensitive flow injection-flame atomic absorption spectrometric (FI-FAAS) method was developed for on-line preconcentration and determination of trace levels of cobalt(II). A mini-column packed with a chloromethylated polystyrene, functionalized with N,N-bis(naphthylideneimino)diethylenetriamine (PS-NAPdien) was used for on-line enrichment of cobalt(II) from samples at pH 7.0. All chemical and flow variables were optimized. Under the optimum conditions, calibration graph was linear over the concentration ranges of 1.0-80.0 and 0.30-40.0 µg L-1 for preconcentration of 10.0 and 20.0 mL solutions, respectively. The limits of detection (LODs) values for preconcentration of 10.0 and 20.0 mL sample solutions were 0.75 and 0.25 µg L-1, respectively. An enrichment factor of 110 for a sample volume of 10.0 mL was obtained. The relative standard deviations for 10 replicate determinations of cobalt(II) at the 10.0 and 60.0 µg L-1 levels were 4.7 and 3.3%, respectively. The accuracy of the proposed method was demonstrated by determining Co(II) in different spiked water samples.
flame atomic absorption spectrometry; on-line preconcentration; flow injection; polystyrene; cobalt(II)
