DETERMINATION OF NITROFURANTOIN, FURAZOLIDONE AND FURALTADONE IN MILKBY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

A HPLC method with coulometric detection has been established to carry out the separation of the three nitrofuran derivatives, nitrofurantoi n, furazolidone and furaltadone. A Nova-Pak C-18 column (150x3.9 mm) a nd a Coulochem II detector from ESA have been used. After obtaining th e hydrodynamic curves of the three compounds in the porous graphite el ectrode a potential of -600 mV was selected as the working potential. The influence of other variables such as mobile phase composition and flow-rate were studied. The mobile phase considered as an optimum was acetonitrile-0.1 M aqueous solution of sodium perchlorate (28:72), wit h 0.5% glacial acetic acid. The oxygen of the mobile phase was removed with a vacuum system on-line and a nitrogen stream was used to remove the oxygen of the samples. The calibration graphs and the detection l imits were established. The method proposed was used, with good result s, for the determination of the three compounds in milk.