Preparation of imidazolidinone compounds as derivatization reagent for diastereomerization and chromatographic separation of chiral organic acids.

A chiral derivatization reagent for application in LC-tandem mass spectrometry (LC-MS/MS)-based detection, benzyl 5-(2-aminoethyl)-3-methyl-4-oxoimidazolidine-1-carboxylate (CIM-C-NH), which can react with the carboxyl group, was synthesized. Both chiral and non-chiral organic acids such as lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, acetic acid, succinic acid, tartaric acid, malic acid, and citramalic acid were derivatized with CIM-C-NH; their derivatives were analyzed by LC-MS/MS. We investigated the enantioseparation of chiral organic acids on an octadecylsilica column and obtained the resolution values within 1.31-2.19 with a mobile phase of HO-CHCN with the exception of malic acid. In contrast, no enantioseparation of the chiral organic acids was observed when benzyl 5-(aminomethyl)-3-methyl-4-oxoimidazolidine-1-carboxylate (CIM-C-NH), which bears fewer methylene units than CIM-C-NH, was used. In addition, the mass spectra of malic acid, tartaric acid, and succinic acid, which have two carboxyl groups, showed product ions of m/z 278, while those of other organic acids showed product ions of m/z 91, corresponding to the benzyl moiety. The proposed method was applied to analyze organic acids in commercial wine, and some organic acids such as d- and l-lactic acid were successfully detected.