Plasmalogens degradation

The lithium chloride solution in the extraction can be replaced with other salts such as ammonium acetate or a weak acid if necessary [33], However, an acidic environment may lead to plasmalogen degradation, thus it should be very cautious. It should be pointed out that although the aqueous phase is usually discarded after extraction, it could be used for analysis of many lipid classes, which largely disperse to it as reported [39],... 

Most cells continually degrade and replace their membrane lipids. For each hydrolyzable bond in a glycerophospholipid, there is a specific hydrolytic enzyme in the lysosome (Fig. 10-15). Phospholipases of the A type remove one of the two fatty acids, producing a lysophospholipid. (These esterases do not attack the ether link of plasmalogens.) Lysophospholipases remove the remaining fatty acid. 

The first chemical synthesis of the phosphate trans-(2), as an unnatural analogue of plasmalogen, bearing a trans-O-vinyl moiety has been achieved by Bittman and co-workers (Scheme 2). The natural cis-(2) was preferentially degraded by HOCl and was more protective than trans- l) against lipid peroxidation induced by a free-radical initiator. 

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. 

Lipid samples containing plasmalogens should not be stored for long periods in solvents containing acetone, methanol or glacial acetic acid, as some rearrangement or other degradation may occur. 

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