Development and optimization of a gas chromatography/mass spectrometry method for the analysis of thermochemolytic degradation products of phthiocerol dimycocerosate waxes found in Mycobacterium tuberculosis.
Bottom Line: The extraction of PDIMs from culture is simple, and their thermochemolysis is carried out automatically online, thus avoiding the time-consuming derivatization steps of hydrolysis and esterification, usually performed offline.For standard PDIMs in petroleum ether, our optimized method gave an excellent linearity (R(2) = 0.99) at concentrations between 0.172 and 27.5 ng/mL, a good precision (RSD = 11.42%), and a limit of detection (LOD) of 100 pg/mL.For the PDIMs extracted from dilutions of M. tuberculosis culture, the method gave good linearity (R(2) = 0.9685) and an estimated LOD of 400 CFU/mL (CFU = colony forming units) in sterile distilled water.
Affiliation: Department of Physical Sciences, Faculty of Science, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK.Show MeSH
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Mentions: Figure 6(a) presents the results obtained when the time taken to transfer the methylated derivatives to the capillary column was varied in the range 2–5.5 min, with the other parameters set as follows: 70 °C start and 380 °C final temperature, 12 °C/s temperature ramping rate, and a standard flow 1.1 mL/min of He carrier gas.
Affiliation: Department of Physical Sciences, Faculty of Science, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK.