Flavonoid compounds in the petals of Hosta HPLC-ESI-MSn analysis of chemical constituents in Semen Ziziphi Spinosae Relationship Between the Composition of Anthocyanins and Flower Color Variation in Hardy Water Lily (Nymphaea spp.) Cultivars HPLC-ESI-MSn analysis of chemical constituents in Semen Ziziphi Spinosae Identification of chemical component from Ixeris sonchifolia and its injection by HPLC-ESI-MSn Mechanisms of catalpol and jasminoidin by electrospray ionization mass spectrometry