Plasmalogens fragmentation

Fhaner, C.J., Liu, S., Zhou, X. and Reid, G.E. (2013) Functional group selective derivati-zation and gas-phase fragmentation reactions of plasmalogen glycerophosphofipids. Mass Spectrom. (Tokyo) 2, S0015. 

A low-concentration of lithium chloride (e.g., 50 mM in aqueous phase) is preferable for lipid extraction for MDMS-SL since the lithium adduct of lipid species can yield unique and informative fragmentation patterns after CID (Part II). Moreover, the weakly acidic conditions resulted from a weak Lewis base of lithium ion and a strong Lewis acid of chloride could improve the extraction efficiency of anionic lipids to a certain degree and could lead to increased intrasource separation of molecular specie of anionic lipid classes from PE species in negative-ion ESI-MS (Chapter 3). Under such weakly acidic conditions, degradation of plasmalogen species does not occur. 

PE, including the plasmalogens, can be detected either as the [M-t-H]" ion in the positive mode or as [M-H] ion in the negative mode, particularly under alkaline conditions [3,4,21]. In the positive mode, PE exhibits a specific NL of 141 (phosphoethanolamine), whereas in the negative mode carboxylate anions from fatty acid fragmentation are the most abundant fragments. 

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