Determination of Isoflavones in Legumes by QuEChERS-Capillary Electrophoresis-Electrospray Ionization-Mass Spectrometry

In this study, a capillary electrophoresis-mass spectrometry method was applied to the determination of isoflavones in samples with low content in these analytes, such as legumes. Sample stacking was used to enhance the sensitivity of the technique. Extraction of the analytes was carried out by a modified approach of QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) methodology, in which the extracts were injected directly into electrophoretic system coupled with mass spectrometry detector. The developed method was validated and applied for the determination of isoflavone aglycones and glycosides in legume samples. The values of the validation parameters and the isoflavone contents found were compared with those obtained by LC-MS/MS. Both methods provided similar results and were comparable in terms of recovery (in the 80-120% range), precision (lower than 10 %) and limits of detection (ranging from 0.20 to 1.8 μg L-1).