The use of biomarker compounds for the identification of bacteria by pyrolysis mass spectrometry

Several recent advances in using biomarkers for bacteria characterization are discussed. A study using Gram-positive and Gram-negative bacteria has been conducted to compare both gas chromatographic and mass spectrometric analyses of the separately isolated and methylated fatty acids to an in situ reaction in which the saponification and methylation of the fatty acids is achieved using tetramethylammonium hydroxide (TMAH). Principal components analysis of the three data sets showed the same three cluster patterns. In situ methylation using TMAH has also been conducted on free nucleotides, oligonucleotides, DNA, various amino acids, and oligopeptides. An increase in the volatility of important biomarkers was observed in all analyses which leads to an increase in the information content of the data. High resolution mass spectrometry has also been applied to the peaks corresponding to a series of biomarker compounds. The data show that most nominal masses are composed of several contributing species. (C) 1997 Elsevier Science B.V.