Stable complexes are required during the ion chromatographic (IC) separation of Fe-polycarboxylic acid complexes. Electrospray ionization mass spectrometry (ESI-MS) was used to identify 1:1 stoichiometric complexes of Fe [HEDTA], Fe [EDTA] 1_ and Fe [DTPA] 2_, and the spectra showed that these Fe complexes were stable in solution. Furthermore, inductively coupled plasma mass spectrometry (ICP-MS) using an octopole reaction system (ORS) reduced polyatomic ion 40Ar16OR interference in the detection of 56Fe via the addition of either H2 or He to the ORS, with He at a flow rate 3.5mLmin_1 being the optimum collision gas. Finally, IC/ICP-MS was used for the separation and detection of Fe complexes with an eluent containing 30mM (NH4) 2HPO4 at pH 8.0, but only Fe [HEDTA], Fe [EDTA] 1_and Fe [DTPA] 2_were observed within 10 min with reasonable resolution. Detection limits in the range of 10-13mg L_1 were achieved using He as the collision gas. The proposed method was used for the determination of Fe species in soil solutions. Copyright # 2010 John Wiley & Sons, Ltd.