Author(s)

Hiroko Tominaga, Tomoe Ishihara, A. K. M. Azad Shah, Rumiko Shimizu, Arnold N. Onyango, Hideyuki Ito, Toshinori Suzuki, Yasuhiro Kondo, Hiroshi Koaze, Koretaro Takahashi, Naomichi Baba

Department of Food Science, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan.
Division of Bioscience, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan.
Faculty of Health and Welfare Science, Okayama Prefectural University, Okayama, Japan.
Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Kobe, Japan.
Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
School of Pharmacy, Shujitsu Univerisity, Okayama, Japan.
Sdivision of Marine Life Science, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan.

New ionization and detection techniques in mass spectrometry have been successfully applied for efficient analyses of complex biological systems. It is, however, still difficult to trace structural changes of a specific molecular species in such systems. In the present study, a molecular probe strategy in combination with tandem electrospray ionization mass spectrometry has been examined using synthetic deuterium-labeled phosphatidylcholine hydroperoxide (PC-OOH/D3) and ethyl-labeled phosphatidylcholine having docosahexaenoic acid side chain (DHA-PC/Et). Administration of a mixture of PC-OOH/D3 and DHA-PC/Et to human blood and human skin surface, followed by extraction and analysis with collision-induced tandem electrospray ionization mass spectrometry demonstrated that metabolites of both molecular probes can be detected simultaneously with strict selectivity. The present method is also found to be useful in tracing chemical changes of the unstable docosahexaenoyl group on the surface of processed fish. The activity of phospholipase A2 can also be assessed using a phospholipid molecular probe with a linoleoyl and a deuteriomethyl group via selective detection of the lyso-phospholipid product by mass spectrometry. The advantage of the present method is that no chromatographic separation is required and analysis can be performed under strictly the same condition for different molecular probes, affording multiple data by one experiment. The present strategy may be useful for tracing time-dependent phenomena in dynamic phospholipid biochemistry, and can be widely used for any biological and food systems.

Molecular Probe; Stable Isotope; Mass Spectrometry; Electrospray Ionization; Lipid Peroxidation; Lipid Oxidation; Skin Surface

H. Tominaga, T. Ishihara, A. Shah, R. Shimizu, A. Onyango, H. Ito, T. Suzuki, Y. Kondo, H. Koaze, K. Takahashi and N. Baba, "Molecular Probes in Tandem Electrospray Ionization Mass Spectrometry: Application to Tracing Chemical Changes of Specific Phospholipid Molecular Species," American Journal of Analytical Chemistry, Vol. 4 No. 10B, 2013, pp. 16-26. doi: 10.4236/ajac.2013.410A2003.