1982 Volume 30 Issue 6 Pages 2119-2126
The electron impact and chemical ionization mass spectra of lysophosphatidic acids and their dimethyl esters were measured by injection of the compounds into a direct inlet system. Dry powders of lysophosphatidic acids were dehydrated on the probe at 200-250°C and the dehydrated lysophosphatidic acids were subjected to electron impact or interaction with ion plasma of the reactant gas, yielding several characteristic ion peaks containing phosphorus. On the other hand, lysophosphatidic acids injected in the probe as solutions in organic solvents were not dehydrated in this temperature range, but were dephosphorylated at highter probe temperatures. When the dimethyl esters were applied to the probe either as powder or solution, they were converted to the monomethyl esters of dehydrated lysophosphatidic acids on the heated probe, possibly by elimination of methanol from the glycerol backbone and polar phosphate portion. The monomethyl esters were also volatilized and subjected to electron impact and chemical ionization, producing ion peaks corresponding to those observed on analysis of dehydrated lysophosphatidic acids.
