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Abstract: 1,10-Phenanthroline (phen) was tested as a complexing agent for on-line preconcentration of iron on RP-C₁₈ material in a microcolumn with flow injection coupled with flame atomic absorption spectrometer (FI-FAAS). The on-line formed Fe(II)-phen complexes were adsorbed on the C₁₈ sorbent material. Various parameters affecting the on-line Fe(II)-phen complex formation and its subsequent adsorption in the microcolumn as well as its elution into the nebulizer of AAS were optimized. A 2.5×10⁻³ mol/L phen in 2% ethanol was on-line mixed with aqueous sample solution acidified with 0.1% (v/v) HCl and allowed to flow through the microcolumn for 30 s. The adsorbed Fe(II)-phen complexes in the microcolumn were eluted with ethanol in 10 s into the nebulizer of AAS. Ascorbic acid (5×10⁻⁴ mol/L) was added to the sample solution for the reduction of Fe(III) to Fe(II). A good precision (RSD=1.1%, n=10), high enrichment factor (19) and sample throughput (90 h⁻¹) with detection limit (3σ) of 3 μg/L were obtained. The method was applied on standard reference materials (i.e. mussel and tomato leaves,) for iron determination and yielded results agreeing well with certified values.

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