DETERMINATION OF CHLOROACETIC ACID, BROMOACETIC ACID AND IODOACETIC ACID IN BEER BY MICROBORE GAS‐LIQUID CHROMATOGRAPHY AND ELECTRON CAPTURE DETECTION

Determination of monohaloacetic acids in beer has been carried out by: 1) percolation of the beer through a C-18 Sep-Pak in order to eliminate the less polar components; 2) acidification of the eluate (pH=0.5) and extraction of the monohaloacetic acids with ethyl acetate; 3) removal of the organic solvent by rotary evaporator and vacuum; 4) methylation of the residue with BFMeOH; 5) extraction of the methyl ester derivatives with hexane; and 6) separation, detection and quantitation by gas-liquid chromatography, using a fused-silica BP-1 (12m × 0.53 mm) microbore column, and electron capture detection. Recovery yields are nearly 100% for all monohaloacetic acids. Detection limits are lower than 0.1, 0.05 and 0.01 ppm for chloroacetic acid, bromoacetic acid and iodoacetic acid, respectively. Seventeen European beers have been analyzed for monohaloacetic acids content, and negative results have been found in all cases.