DETERMINATION OF DISSOLVED AND ADSORBED EDTA SPECIES IN WATER AND SEDIMENTS BY HPLC

This paper describes a method for determining EDTA species in various environmental samples at low molar concentrations by high-performance liquid chromatography (HPLC). Distinction between Fe(III)EDTA and all the other species can be made. NiEDTA can be detected semiquantitative ly. The fraction of EDTA adsorbed to suspended particles or to sedimen ts can be determined after desorption with phosphate. After complexati on with Fe(III), the EDTA is detected by reversed-phase ion-pair liqui d chromatography as the Fe(III)EDTA complex at a wavelength of 258 nm, The behavior of a variety of metal-EDTA complexes during analysis was checked. Determination of different EDTA species (Fe(III)EDTA, NiEDTA , and adsorbed EDTA) is possible in river water, groundwater, and effl uents from wastewater treatment plants. FeT(III)EDTA was found to be t he main species, at 30-70%; NiEDTA was <10% in most of the samples, Ad sorbed EDTA was detected in suspended particles from rivers and wastew ater treatment plants and in sediment cores from a lake. The method is suitable for a variety of different samples with different concentrat ion ranges.