Liquid chromatographic determination of 2-furaldehyde and 5-hydroxymethyl-2-furaldehyde in beer

A method for the determination of 2-furaldehyde (F) and 5-hydroxymethyl-2-furaldehyde (HMF) in beer by liquid chromatography (LC) is described. The method is based on the formation of the 2,4-dinitrophenylhydrazones of carbonyl compounds and subsequent reversed-phase separation of these derivatives. Derivatization is carried out by utilizing an acidic solution of 2,4-dinitrophenylhydrazine in acetonitrile. Precipitation of the derivatives of carbonyl compounds is thus avoided and direct injection of the sample into the LC system is possible. The procedure offers a high specificity, since the derivatives of F and HMF are well separated from the other components of the mixture under examination. Recoveries of 91–98% were obtained from beer spiked at different levels with both analytes. The detection limit is in the order of 10−8 mol/l and the reproducibility (mean of six determinations) is ±5% for F and ±3% for HMF.