LIQUID-CHROMATOGRAPHIC DETERMINATION OF 2-FURALDEHYDE AND 5-HYDROXYMETHYL-2-FURALDEHYDE IN BEER

A method for the determination of 2-furaldehyde (F) and 5-hydroxymethy l-2-furaldehyde (HMF) in beer by liquid chromatography (LC) is describ ed. The method is based on the formation of the 2,4-dinitrophenylhydra zones of carbonyl compounds and subsequent reversed-phase separation o f these derivatives. Derivatization is carried out by utilizing an aci dic solution of 2,4-dinitrophenylhydrazine in acetonitrile. Precipitat ion of the derivatives of carbonyl compounds is thus avoided and direc t injection of the sample into the LC system is possible. The procedur e offers a high specificity, since the derivatives of F and HMF are we ll separated from the other components of the mixture under examinatio n. Recoveries of 91-98% were obtained from beer spiked at different le vels with both analytes. The detection limit is in the order of 10(-8) mol/l and the reproducibility (mean of six determinations) is +/-5% f or F and +/-3% for HMF.