ANALYSIS OF BEER CARBONYLS AT THE PART PER BILLION LEVEL BY COMBINED LIQUID CHROMATOGRAPHY AND HIGH PRESSURE LIQUID CHROMATOGRAPHY

Abstract

Carbonyl compounds have been isolated from lager by low pressure distillation and recovered from the distillate as their 2,4-dinitrophenylhydrazone derivatives. The derivatives were subsequently separated into four monocarbonyl classes on a magnesia-silica gel column, and then each class resolved by HPLC. This technique has proved to be sensitive to carbonyls in lager at concentrations below 0·1 ppb and shows a high degree of resolution. So far, twelve methyl ketones, eleven saturated aldehydes and eight alkenals have been separated. The content of both fresh and aged lagers has been examined and changes in concentration discussed in relation to their reported taste thresholds.