Simultaneous determination of volatile and non-volatile acidic fermentation products of anaerobes by capillary gas chromatography

A method previously used for the analysis of organic acids in silage has been applied to the detection and quantification of acidic fermentation products (C₁ to C₆ volatile fatty acids, lactic and succinic acid) of rumen bacteria and anaerobic fungi grown in pure culture. The acids were converted to tertiary butyldimethylsilyl derivatives prior to separation on a 30 m DB1 capillary gas chromatographic column. The quantitative recoveries of formic and succinic acids were found to be comparable to the recoveries of other acids reported in the original study. The quantitative recovery of lactic acid was found to be dependent on storage of the samples at ambient temperature for at least 24 h following derivatization. The simultaneous determination of a wide range of volatile and non-volatile acidic products is an important feature of this method.