Abstrvonoids fromact to establish a met hod for deter mining to talflavonoids from the extract
of Ginkgo leaf in too thpaste by HPLC,with the indices of quercetin,kaempferol and isorhamnetin. Method:Agilent ZO RBAX Eclipse XDB C 18 column (Analytical 4.6 250mm 5Micron),
mobilephase!V(Meoh)!V(0.4%H3PO4)=55! 45;flowrate:1.0ml/min;=360nm;column temperature:40;sample volume:20L.Results the showed that the calibration curve of quercetin, kaempferol and isorhamnet in were line in range of 2.1-21.0g/ml,1.8-18.0g/ml and 0,42-4.2g/ml,
respectively;correlation coefficients were 0.9999,0.9999 and 0.9998;the absolute recoveries of
quercetin,kaempferol and isorhamnetin were 97.7%、98.3% and 97.6%.This method is easy,flexible and exact for determination of total flavonoids from the extract of Ginkgo leaf in toothpaste.