Detection of alcohols and volatile fatty acids by head-space gas chromatography in identification of anaerobic bacteria

Abstract

A head-space gas chromatographic technique for the analysis of volatile bacterial metabolites is described. Bacteroides fragilis, Clostridium perfringens and Propionibacterium acnes, cultured in a glucose-containing peptone yeast extract medium, were studied. The head-space technique was compared with the injection of the complete liquid culture medium, and solvent extracts thereof, into the gas chromatograph. Volatile fatty acids could be detected by all 3 methods, but alcohols produced by C. perfringens and P. acnes were detectable only in the head-space chromatograms. Both FFAP and Porapak Q were used as gas chromatography stationary phase. Porapak Q was found more suitable than FFAP for the separation of alcohols. The head-space technique requires a minimum of preparation before the analysis and is well suited to automation.