Submitted to: United States-Japan Cooperative Program in Natural Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2008
Publication Date: December 15, 2008
Citation: Byrdwell, W.C. 2008. Dual parallel mass apectrometry (LC1/MS2 and LC2/MS2) for lipid and vitamin D analysis. Proceedings of the United States-Japan Cooperative Program in Natural Resources. 37:179-180. Interpretive Summary: Mass spectrometry is a technique for measuring the masses of components in order to identify them and determine how much is present. Different types of mass spectrometry provide different types of information, so no one single technique is ideal. We have demonstrated several different approaches to coupling two types of mass spectrometers together to produce complementary information that can answer more questions than any one single technique. These approaches have been applied to lipids (fats) from cow brain, canola oil, cow milk, and fish extracts and to vitamin D from milk, orange juice, cereal, salmon, and other foods.
Technical Abstract: Atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and electrospray ionization (ESI) MS are complementary techniques that provide different types of information for lipids such as triacylglycerols, phospholipids, and fat-soluble vitamins. Since no one technique is by itself ideal, we routinely employ two mass spectrometers in parallel to provide APCI-MS and ES1-MS, MS/MS and MSn data. Dual parallel mass spectrometers have been attached to the same chromatographic system to provide two or more types of information from components in the same column effluent, referred to as an LC1/MS2 approach. Alternatively, two chromatographic systems have been attached in a column-switching configuration to perform a total lipid analysis of both polar and non-polar lipids on normal-phase (NP) and reversed-phase (RP) systems, respectively, with detection by two different mass spectrometers simultaneously operated with different ionization modes. This is referred to as an LC2/MS2 arrangement. An LC1/MS2 approach has also been used for vitamin D analysis in foods, which allows accurate quantification using APCI-MS in SIM mode with parallel acquisition of APCI-MS for qualitative monitoring of interfering species.