HPLC - New way of determining carbonyls in beer.

Abstract

Carbonyl compounds, especially aldehydes, notably affect the taste of beer. Although the concentration of these substances in beer is very low, for most of these, the threshold concentration of the taste reception is also very low. That9s why in brewing they belong amongst the most intensively monitored substances. The authors of this report focused on possibilities of using liquid chromatography particularly in a combination with Solid Phase Extraction with current derivation 2,4 - dinitrophenylhydrazine (DNPH). Analytes were displaced from the sample by nitrogen and captured on a SPE column, from which they were eluted by acetonitrile and analyzed using HPLC with a PAD detector. The following were being determined: acetaldehyde, diacetyl, furfural, 2-methylbutanal, 3-methylbutanal, 2-methylpropanal, pentanal, hexanal and (E)-2-nonenal. The spectra of the individual hydrazones were measured, and the content of carbonyl compounds was determined in ordinarily commercially available selected beers. The contents of individual substances were found and they are consistent with previously published concentrations determined using other analytical methods.Carbonyl compounds, especially aldehydes, notably affect the taste of beer. Although the concentration of these substances in beer is very low, for most of these, the threshold concentration of the taste reception is also very low. That9s why in brewing they belong amongst the most intensively monitored substances. The authors of this report focused on possibilities of using liquid chromatography particularly in a combination with Solid Phase Extraction with current derivation 2,4 - dinitrophenylhydrazine (DNPH). Analytes were displaced from the sample by nitrogen and captured on a SPE column, from which they were eluted by acetonitrile and analyzed using HPLC with a PAD detector. The following were being determined: acetaldehyde, diacetyl, furfural, 2-methylbutanal, 3-methylbutanal, 2-methylpropanal, pentanal, hexanal and (E)-2-nonenal. The spectra of the individual hydrazones were measured, and the content of carbonyl compounds was determined in ordinarily commercially available selected beers. The contents of individual substances were found and they are consistent with previously published concentrations determined using other analytical methods.

Keywords

• carbonyls
• beer
• taste
• HPLC
• solid phase extraction