DETERMINATION OF GLYOXAL, METHYLGLYOXAL, AND DIACETYL IN SELECTED BEER AND WINE, BY HPLC WITH UV SPECTROPHOTOMETRIC DETECTION, AFTER DERIVATIZATION WITH o-PHENYLENEDIAMINE

Abstract

The α-diketones glyoxal, methylglyoxal, and diacetyl were determined in selected beer and wine using a procedure involving the use of C₁₈ solid phase extraction columns to remove interferences and derivatization of the compounds with o-phenylenediamine to form quinoxalines, which are separated by HPLC and detected using UV spectrophotometric detection.

Interferences were more difficult to remove in the case of beer, due to the higher complexity of the matrix and because the concentrations of the compounds were lower (higher for methylglyoxal and lower for diacetyl, but all in the 10⁻⁷ M region). The determination was easier to implement in the case of wine as the typical concentrations of the compounds were about ten times higher, with methylglyoxal being the more abundant compound found.

ACKNOWLEDGMENTS

A. A. B., J. A. R., and P. J. A. thank Fundação para a Ciência e a Tecnologia (F.C.T.) for financial support. This work was patronized and financed by Program Praxis XXI and by FEDER, as part of the Project 2/2.1/TPAR/463/95.