Determination of glyoxal, methylglyoxal, and diacetyl in selected beer andwine, by HPLC with UV spectrophotometric detection, after derivatization with o-phenylenediamine

The alpha-diketones glyoxal, methylglyoxal, and diacetyl were determined in selected beer and wine using a procedure involving the use of C-18 solid p hase extraction columns to remove interferences and derivatization of the c ompounds 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 comp ounds 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 c ase of wine as the typical concentrations of the compounds were about ten t imes higher, with methylglyoxal being the more abundant compound found.