Extraction of lipids from bacterial cells or sewage sludge samples followed by simple and rapid extraction procedures and room temperature esterification with pentafluorobenzylbromide allowed combined determinations of poly-p-hydroxyalkanoate constituents and fatty acids. Capillary gas chromatography and flame ionization or mass spectrometric detection was used. Flame ionization permitted determination with a coefficient of variation ranging from 10 to 27% at the picomolar level, whereas quantitative chemical ionization mass spectrometry afforded sensitivities for poly-p-hydroxyalkanoate constituuents in the attomolar range. The latter technique suggests the possibility of measuring such components in bacterial assemblies with as few as 102 cells. With the described technique using flame ionization detection, it was possible to study the rapid formation of poly- ,-hydroxyalkanoate during feeding of a starved marine bacterium isolate with a complex medium or glucose and correlate the findings to changes in cell volumes. Mass spectrometric detection of short
Coded sputum specimens from patients with tuberculous (8 specimens) and nontuberculous (15 specimens) pneumonia were analyzed for tuberculostearic acid by selected-ion monitoring of the pentafluorobenzyl ester derivative by using negative-ion mass spectrometry. The analytical results agreed with those from culturing of the specimens, except in three cases in which the chromatograms were difficult to interpret owing to insufficient amounts of sputa available. Negative-ion mass spectrometry provided superior sensitivity and selectivity for detection of tuberculostearic acid compared with the previously used gas chromatographic-mass spectrometric methods. The technique reported here should have considerable potential for the rapid diagnosis of pulmonary tuberculosis by direct analysis of sputum.
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