DETERMINATION OF ETHYLENEDIAMINETETRAACETIC ACID AND ITS SALTS IN CANNED MUSHROOMS BY REVERSED-PHASE ION-PAIR LIQUID-CHROMATOGRAPHY

A method for the determination of ethylenediaminetetraacetic acid (EDTA) in the surrounding liquid of canned mushrooms, based on reversed-phase ion-pair high-performance liquid chromatography (HPLC), was developed. Sample pretreatment simply consists in addition of copper(II) chloride and ascorbic acid to the filtered sample and microfiltration prior to injection into the HPLC system. The copper(II)-EDTA complex thus formed is separated with a water-methanol mobile phase containing tetrabutylammonium as the counter ion at pH 4.0 and UV detection is applied at 300 nm. Iron(III) concentrations up to 33 mg/l do not interfere. The recovery is 105.6 +/- 3.0% at a level of 18 mg/l EDTA and 101.5 +/- 0.8% at a level of 178 mg/l EDTA. The method is linear in the range 7-178 mg/l EDTA. The repeatability of the procedure is 5 mg/l EDTA (n = 20). The limit of determination is 10 mg/l EDTA. The day-to-day (n = 10) relative standard deviation is 2.3%.