Determination of ethylenediaminetetraacetic acid at very low concentrations by high-performance liquid chromatography coupled with electrospray mass spectrometry.

Ethylenediaminetetraacetic acid (EDTA) is a metal complexing agent which is commonly used for removing metallic surface contaminations. But its presence in aqueous industrial effluents or in wastes, by example those which are generated from nuclear power facilities, is forbidden or strictly regulated by the legislation. The implementation of high-performance liquid chromatography coupled with mass spectrometry (MS) via an electrospray interface has exhibited a powerful capacity in the measurement of this complexing agent, in the form of its iron complex. The complex is eluted through a reversed stationary phase under slightly acidic conditions and the detection is performed by mass spectrometry in the single ion monitoring mode. This technique has allowed us to reach a detection limit of about 1 microg/l in EDTA for only 20 microl injected without any previous preconcentration, and to solve some analytical interferences observed in the case of industrial effluents with other analytical techniques such as ion chromatography.