On-line study of flavonoids of Trollius chinensis Bunge binding to DNA with ethidium bromide using a novel combination of chromatographic, mass spectrometric and fluorescence techniques

► Developed a novel online analytical method HPLC-DAD-ESI-IT-TOF-MSn DNA-EB-FLD. ► Identified 18 constituents and six were first found in Trollius chinensis Bunge. ► 16 constituents accounted for binding to DNA. ► Correlate chemical profile with DNA activity without isolation and purification.