A:
Thin-Layer Chromatographic Identification Test á201ñ
Test solution
Finely powder American Ginseng.Transfer 1.0g of this powder to a 25-mLflask fitted with a reflux condenser.Add 10.0mLof a mixture of water and methanol (13:7),and heat under reflux for 15minutes.Cool,filter,and dilute the filtrate with methanol to 10.0mL.
Application volume:
20µL.
Developing solvent system 1
Prepare a mixture of chloroform,methanol,and water (13:7:2),and use the lower phase.
Developing solvent system 2
Prepare a mixture of water,butyl alcohol,and ethyl acetate (5:4:1),and use the upper phase.
Spray reagent
Dissolve 0.5mLof anisaldehyde in 10mLof glacial acetic acid,add 85mLof methanol,mix,carefully add 5mLof sulfuric acid,and mix.
Procedure
Proceed as directed in the chapter.Develop the chromatograms in a chamber containing
Developing solvent system 1until the solvent front has moved about 10.5cm from the origin.Remove the plates from the chromatographic chamber,and allow to dry.Turn the plates 90

,and develop in a chamber containing
Developing solvent system 2until the solvent front has moved about 10.5cm from the origin.Remove the plates from the chromatographic chamber,and allow to dry.Spray with
Spray reagent.Heat the plates at 105

to 110

for about 10minutes,and examine.The order,from top to bottom,of ginsenosides on the chromatographic plates is Rg
2(on left)and Rg
1(on right),Rf,Re,Rd,Rc,Rb
2(on left)and Rb
1(on right),and Ro.Ginsenosides Rg
2,Rg
1,Rf,Re,and Rd are found on the upper half of the plates;the remaining ginsenosides are found on the lower half after chromatographing with
Developing solvent system 2.The chromatogram obtained from
Standard solution 1does not exhibit a spot for ginsenoside Rf.The chromatogram obtained from
Standard solution 2exhibits a spot for ginsenoside Rf.The spots on the chromatogram from the
Test solutioncorrespond to those on the chromatogram from
Standard solution 1.