Determination of ethylenediaminetetraacetic acid in sea water by solid-phase extraction and high-performance liquid chromatography

The chelating agent EDTA is widely used, and as a result is showing up widely in the aquatic environment. Here we describe a preconcentration procedure for measuring EDTA concentration in sea water samples by HPLC. The procedure consists of forming an Fe(III) complex followed by solid-phase extraction using an activated carbon cartridge. After the preconcentration, EDTA was quantified by HPLC with ultraviolet detection (260 nm). The enrichment permitted the determination of EDTA at concentrations as low as 1 nM. Good recoveries were obtained for both brackish and full-strength sea water with high repeatability (RSD < 6%). The method was applied to sea water samples taken from near the mouth of the Oyabe River in Japan.

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► EDTA in sea water was analyzed by HPLC combined with a new preconcentration procedure.
► Solid-phase extraction using activated carbon was applied for the sample preconcentration.
► The enrichment permitted the determination of EDTA at concentrations as low as 1.0 nM.
► Good recoveries were obtained for both brackish and full-strength sea water.