An ion chromatography-electrospray mass spectrometry (IC-MS) method was developed to quantify the metal complexes of ethylenediaminetetra acetic acid (EDTA) in soil solution and plant xylem exudate. Suitable separation of the metal-EDTA complexes was achieved on a Dionex ASS column using 2 mM Na{sub}2CO{sub}3 as the eluant. However, satisfactory detection by eluant suppressed ICMS, in either the positive or negative ion detection mode, could not be attained. A new eluant that still attained suitable separation and produced ionic species that could be detected by MS in the negative ion mode was developed. The eluant consisted of 2.5 mM (NH{sub}4){sub}2CO{sub}3, 9.7 mM NH{sub}4OH, and 4 (v/v) methanol and had a pH 9.9. Even though eluant suppressed IC-MS degraded detection limits by a factor of 4 over the nonsuppressed system, using the retention time and not the m/z (mass-to-charge ratio) of the intact chelate for identification, the latter allowed the metal complexes to be detected intact and was optimized for the analysis of environmental samples. The number of metal-EDTA species that could be detected was limited by the eluant used for ion chromatography (i.e. only those c6mplexes that were stable at high pH), with metal-EDTA complexes of Al, Cd, Cu, Co, Mn, Ni, Pb, and Zn being adequately resolved. Iron(III), Ca, MgEDTA, and EDTA itself were not detected. Detection limits for the various complexes ranged from 0.1 to 1 μM.
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