Submitted to: Journal of Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2009
Publication Date: 7/2/2009
Citation: Breksa III, A.P., Hidalgo, M., Lee-Yuen, M. 2009. Liquid Chromatography-Electrospray Ionization Mass Spectrometry Method for the Rapid Identification of Citrus Limonoid Glucosides in Citrus Juices and Extracts. Journal of Food Chemistry. 117(4)739-744. Interpretive Summary: Our goal was to develop a rapid and robust LC-MS method to assist us in our efforts to characterize the content and character of limonoid glucosides found in citrus juices, extracts and fractions obtained from our isolation efforts. The majority of methods described thus far for the HPLC and LC-MS analysis of limonoid glucosides have relied upon C-18 stationary phases. In this report, we described our evaluation of a phenyl stationary phase as an alternative to C-18 and reported that in addition to resolving the analytes of interest, the phenyl stationary phase, when compared to C-18 phases, also exhibits differences in selectivity that might further be exploited in our efforts to isolate limonoid glucosides. Additionally, we demonstrated that the chromatography is rapid and robust, and when paired with mass spectral detection, yields a method that is applicable to the analysis of samples with complex matrices. Furthermore, we believe that this method and its use in conjunction with the colorimetric estimation of the total limonoid glucoside concentration, will be of value to those with experience in the analysis of citrus limonoid glucosides and equally valuable to other researchers that do not have the means or resources to obtain analytical standards, but wish to evaluate citrus samples for their limonoid glucoside content and character.
Technical Abstract: A rapid and selective liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method to screen citrus samples for limonoid glucosides and estimate their relative concentrations has been developed. This method utilizes a phenyl stationary phase, whereas previous methods have relied on C-18. Samples may be analyzed directly without treatment, other than dilution. Areas from the extracted mass signals for individual limonoid glucosides were normalized against the sum of the areas to establish their relative concentrations. The method was successfully applied to the analysis of various juice, extracts and liquid samples of partially purified limonoid glucosides.