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The suitability of 1-nitroso-2-naphthol(NN) as a complexing agent for on-line preconcentration of cobalt eluted on the C_(18) microcolumn by means of the FI-FAAS system was tested. Various parameters affecting the complex formation and its elution were optimized. A 2.3×10~(-3) mol/L reagent solution and the aqueous sample solution acidified with 0.1％ (volume fraction) nitric acid were on-line mixed (6.4 mL/min) on a reaction coil set at (65±1)℃ and flowed through the microcolumn for 30 s. The pH of the mixed solution was adjusted to 3—4 with HNO_3(1 mol/L) or NaOH(1 mol/L). The adsorbed complexes in the microcolumn were eluted into the nebulizer of FAAS in 10 s with ethanol acidified with 1％ HNO_3(3.0 mL/min). A good precision(1.6％ for 100μg/L Co(Ⅱ), n=10), a high enrichment factor 17.2, with detection limit (3σ) 3.2μg/L, and sample throughput (90 h~(-1)) were obtained. The method was applied to the certified reference materials(CRMs), NBS-362 and NBS-364, for the determination of cobalt and the results were in good agreement with the certified values.
The suitability of 1-nitroso-2-naphthol (NN) as a complexing agent for on-line preconcentration of cobalt eluted on the C_ (18) microcolumn by means of the FI-FAAS system was tested. A 2.3 × 10 -3 mol / L reagent solution and the aqueous sample solution acidified with 0.1% (volume fraction) nitric acid were in-line mixed (6.4 mL / min) on a reaction coil set at (65 ± 1) ° C and flowed through the microcolumn for 30 s. The pH of the mixed solution was adjusted to 3-4 with HNO_3 (1 mol / L) or NaOH (1 mol / L). The adsorbed complexes in the microcolumn were eluted into the nebulizer of FAAS in 10 s with ethanol acidified with 1% HNO 3 (3.0 mL / min). A good precision (1.6% for 100 μg / L Co , with detection limit (3σ) 3.2 μg / L, and sample throughput (90 h -1) were obtained. The method was applied to the certified reference materials (CRMs), NBS-362 and NBS- dete rmination of cobalt and the results were in good agreement with the certified values.