Characterization of phenolic and other polar compounds in a lemon verbena extract by capillary electrophoresis-electrospray ionization-mass spectrometry.

In this study, a CE-MS method has been developed to carry out the qualitative characterization of a lemon verbena (Lippia citriodora) extract for the first time. The CE and ESI-MS parameters were optimized with respect to resolution, analysis time and peak shape in order to maximize the number of compounds detected and the sensitivity of their determination. The use of two different MS analyzers, TOF-MS and IT-MS, enabled the tentative identification of the major components of this extract. Thus, using this method, 16 compounds were determined. Some of them have been previously identified by HPLC methods, although four compounds were also found for the first time in lemon verbena such as asperuloside, tuberonic acid glucoside or 5'-hydroxyjasmonic acid 5'-O-glucoside, shanzhiside and ixoside. These results demonstrate that CE-MS generates data complementary to those obtainable by HPLC-MS and it is particularly suited to the analysis of plant metabolites.