Abstract
The analysis of triacylglycerols and phospholipids - phosphatidylcholines allowed the use of shotgun lipidomics to identify very long-chain fatty acids and very long-chain polyunsaturated fatty acids in microalgae. These fatty acids were determined in triacylglycerols by positive electrospray ionization of neutral loss scans of different fatty acids, e.g. 24:0, 24:19, 1 omega 9, 24:6 omega 3, 26:0, 26:1 omega 9, 28:0, 28:1 omega 9, 28:2 omega 6 and 28:8 omega 3.
Likewise, very long-chain fatty acids in phosphatidylcholines were identified by negative electrospray ionization mass spectrometry in the selected ion-monitoring of the two most important ions (R1COO- and R2COO-). The limit of detection was determined at 10 nmol/L (similar to 11 pg/mu L) in triacylglycerols and 8.6 nmoles/L (similar to 8 pg/mu L) in phosphatidylcholines.
The use of liquid chromatography-mass spectrometry is suitable for very long-chain polyunsaturated fatty acids with up to 8 double bonds due to the time of analysis as well as for reasons of lower thermal stability of polyunsaturated fatty acids towards saturated fatty acids, but gas chromatography-mass spectrometry is better suited for the analysis of saturated very long-chain fatty acids.