Submitted to: Analytical and Bioanalytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 2, 2006
Publication Date: March 1, 2007
Citation: Chen, P., Wolf, W.R. 2006. LC/UV/MS-MRM for the simultaneous determination of water-soluble vitamins in multi-vitamin dietary supplements. Analytical and Bioanalytical Chemistry, 387(7):2441-2448. Interpretive Summary: A fast LC/MS method has been developed and validated for quantification of cichoric acid, a key bio-marker in echinacrea purpurea (E. Purpurea) aerial-parts based dietary supplements. The method is the first analytical method intended for quantitative determination of cichoric acid content in E. purpurea aerial-parts based dietary supplements in less than 5 minutes per sample. Water/methanol (3:7)-soluble extracts of six commercially available E. purpurea aerial-parts based dietary supplements were analyzed by the LC/MS method. The method permitted rapid characterization and quantitation of cichoric acid and could be applied to assess the qualities of different E. purpurea aerial-part preparations.
Technical Abstract: A new, rapid, and reproducible reversed-phased liquid chromatographic (LC) method with mass spectroscopic detection has been developed and validated for quantification of cichoric acid, a key biomarker, in Echinacea purpurea aerial-parts based dietary supplements (EPADS). It involves the use of a short Phenomenex Hydro-RP C18 column (4 µm, 50 mm × 3.0 mm id) and a simple isocratic mobile phase profile. Selective-ion monitoring (SIM) at m/z 472.8 provided good sensitivity and a single peak chromatogram for cichoric acid despite a complex matrix. The limit of detection (LOD) is 0.03 µg/ml and the limit of quantitation (LOQ) is 0.1 µg/ml. Water/ethanol (1:1) soluble extracts of six commercially available EPADS were first profiled using a traditional HPLC/UV method. Their UV chromatograms were compared and cichoric acid was identified to be a key biomarker for EPADS. Then the samples were analyzed by the LC/MS method. The throughput increased 10 to 20 folds compared to traditional HPLC methods reported. The high-throughput method was feasible because the mass spectrometer was operated in SIM for cichoric acid only, thus eliminated interferences from other components existed in the complex matrices of the extractions of E. purpurea aerial-part preparations. The method does not require any sample clean up steps except filtration.