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Mass Spectrometry of the Lithium Adducts of Diacylglycerols Containing Hydroxy FA in Castor Oil and Two Normal FA
Author(s) -
Lin JiannTsyh,
Chen Grace Q.,
Hou Ching T.
Publication year - 2013
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-012-2136-5
Subject(s) - chemistry , adduct , mass spectrometry , electrospray ionization , lithium (medication) , castor oil , chromatography , organic chemistry , biology , endocrinology
Castor oil can be used in industry. The molecular species of triacylglycerols containing hydroxy fatty acids (FA) in castor oil have been identified. We report here the identification of twelve diacylglycerols (DAG) containing hydroxy FA in castor oil using positive ion electrospray ionization mass spectrometry of the lithium adducts. They were RR (diricinolein, R is ricinoleate), RL, RS, R‐diOH18:0, R‐diOH18:1, R‐diOH18:2, R‐triOH18:0, R‐triOH18:1, R‐triOH18:2, diOH18:0‐diOH18:1, diOH18:1‐diOH18:1 and diOH18:1‐diOH18:2. The MS 2 fragment ions, [M + Li − FA] + and [FA + Li] + , from the lithium adducts of DAG containing hydroxy FA (one or two hydroxy FA), were used for the identification. The additional fragment ions from the neutral losses of FA lithium salts [M + Li − FALi] + were used for the identification of eleven DAG containing two normal FA in a soybean oil bioconversion product. The MS 2 fragment ions from the neutral losses of FA lithium salts [M + Li − FALi] + were not detected from the DAG containing hydroxy FA. The DAG containing FA with more hydroxyl groups than the other FA on the same DAG molecule tended to have a prominent fragment ion [FA + Li] + and an undetectable fragment ion [M + Li − FA] + while the FA was the more hydroxylated FA. Also the less hydroxylated FA of a DAG tended to have a prominent fragment ion [M + Li − FA] + and an undetectable fragment ion [FA + Li] + while the FA was the less hydroxylated FA.