Chapter five


Analysis of Fatty Acids by APCI-MS


Tomá˘s ˘Rezanka and Jaroslav Votruba


Institute of Microbiology, Videnska 1083, 14220 Prague, Czech Republic




The integration of chromatographic and spectroscopic analytical techniques now represents the mainstream in advanced analysis of natural compounds. Usually, this approach can be described as a two-step procedure. In the first step, the mixture of compounds is separated by a suitable technique such as gas chromatography (GC) or high-performance liquid chromatography (HPLC). Second, a specific detection method, for example, mass spectrometry (MS), is used to obtain structural information about individual substances. In an ideal case, this approach makes it possible to identify simultaneously the individual compounds in the sample, or at least estimate their chemical structures.

A combination of GC and MS techniques is currently widely used. This approach links together in one measurement the separation, with high efficiency, of individual chemical species by GC, plus the identification of their chemical structures. However, the GC-MS technique is limited to the identification of volatile compounds. In the case of poorly volatile compounds, chemical derivatization of the sample must be performed before using GC-MS. The inherent limitation of direct measurement by the volatility, as well as the thermal degradation of labile compounds, stimulated research into a more sophisticated combination of techniques, that is, LC-MS, but the two techniques show low compatibility. In general, MS operates at a high vacuum in the range of 10–3 to 10–5 Pa, whereas the output from HPLC is a liquid phase with a flow rate between 0.5 and 2 mL/min at atmospheric pressure. The feasibility of LC-MS coupling thus depends on the fast and efficient evaporation of the liquid phase from HPLC and reduction of superfluous mobile phase in the input flow to the mass spectrometer. Various devices have been designed for this purpose.

Modern Methods for Lipid AnalysiS by Liquid Chromatography/ mass spectrometry and Related Techniques

Resources for Lipid Analysis in the 21st Century

Contact the author:


Dr. Tomas Rezanka and Jaroslav Votruba

Institute for Microbiology

Videnska 1083

14220 Prague, Czech Republic



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