Fast screening of flavonoids from switchgrass and Mikania micrantha by liquid chromatography hybrid-ion trap time-of-flight mass spectrometry
Weeds contain flavonoids that have antioxygenation, circulation improvement, and cholesterol-lowering effects. The novel and widely applicable method of liquid chromatography hybrid-ion trap time-of-flight mass spectrometry (LC/MS-IT-TOF) was established to quickly screen non-target flavonoid components from weeds in this study. This method required two steps, the detection of characteristic ions of the flavonoid components and their identification by comparison of their manual fragments. Then all non-target and semi-target flavonoid components could be directly determined via automatically screening out the characteristic fragments. This method was successfully applied for the fast determination of flavonoid components in the stem extract of switchgrass. One glycoside of isorhamnetin (isorhamnetin-3-O-rutinoside) and six glycosides of quercetin (quercetin-3-O-galactoside, quercetin-3-O-glucoside, rutin, quercetin-3-O-xyloside, quercetin-3-O-arabinoside, and quercetin-3-O-rhamnoside) were detected in switchgrass. In addition, syringaresinol hexoside was also found in this weed. Among these compounds, six (quercetin-3-O-galactoside, quercetin-3-O-glucoside, quercetin-3-O-xyloside, quercetin-3-O-arabinoside, isorhamnetin-3-O-rutinoside and syringaresinol hexoside) were first found in switchgrass. In Mikania micrantha, three more flavonoid components were detected than that in our previous study. This efficient method could be universally applied for the identification of components in some complex matrix samples like food samples and plant samples.