HomePh.D. Study at IOCBArchive - 2010Analytical Chemistry

Analytical Chemistry

Tutor RNDr. Josef Cvačka, Ph.D.
Team Mass Spectrometry (Josef Cvačka)
Topic Determination of double bond positions in lipids by atmospheric pressure ionization mass spectrometry
Faculty PřF UK

Lipids fulfill numerous crucial tasks in the living cells, participating in their development and pathology. In human, many diseases, e.g., cardiovascular problems, obesity, or inborn errors of metabolism are directly related to lipids. Biological functions and activities of lipids depend on their structure. Most lipids contain fatty acid chains. The number of double bonds, their configurations and positions within the chain greatly affects their biological activity. Gas chromatography with mass spectrometry detection is a traditional method for determining positions of double bonds in lipids. This approach is highly successful, but often requires lipids to be hydrolyzed to liberate fatty acids. Such procedures do not preserve information on the structure of the original lipids, i.e., how and in which combinations were the fatty acids bonded.

The aim of this project is to develop procedures for determining double bond positions in intact lipids without hydrolysis, using atmospheric pressure ionization (ESI, APCI) mass spectrometry. Double bonds in lipids will be derivatized using various procedures (hydroxylation, epoxidation, alkylthiolation, halogenation etc.) and mass spectra of the reaction products will be studied. The derivatives providing fragments indicating original position of double bonds will be selected and used for solving selected biological problems. HPLC/MSn methods will be developed for these derivatives to allow determination of double bond positions in mixtures of lipids. HPLC and UHPLC systems with mass spectrometry detectors allowing low-resolution (ion trap) and high-resolution (orbitrap) measurement are available. The derivatization reactions will be tested using neutral lipids (hydrocarbons, esters, acylglycerols) and polar lipids (phospholipids, glycolipids).