Determination of ethylenediamine tetraacetic acid in injection forms by ion-pair chromatography.

A high performance liquid chromatographic method was developed for the determination of ethylenediamine tetraacetic acid (EDTA) in injection forms. The method consists of direct extraction of the samples with ethyl acetate; the organic layers were evaporated to dryness and further diluted to a 0.025% (w/v) copper nitrate in order to achive the formation of the EDTA-copper solution complex. The chromatographic separation was performed on a C8 Hypersil column. The mobile phase consisted of a mixture of acetonitrile-0.015 M tetrabutylammonium hydroxide (10:90, v/v), (pH* 7.0) pumped at a flow rate of 1.5 ml min(-1). The UV detector was operated at 300 nm. Correlation coefficients of the calibration graphs were better than 0.9995, relative standard deviation was less than 2.5%. Detection limit of EDTA was found to be 1.97 microg ml(-1).