A:
Thin-Layer Chromatographic Identification Test á201ñ
Adsorbent:
0.2-mm layer of chromatographic silica gel mixture on a high-performance thin-layer chromatographic plate.
Extraction column
Use a solid-phase extraction column that contains packing L1with a sorbent mass to column volume ratio of 360mg per 0.85mL,or equivalent.Condition the column prior to use by washing with 3mLof methanol and with 8mLof water.
Test solution
Transfer about 1.0g of Powdered Extract,accurately weighed,to a 25-mLvolumetric flask,and dissolve in water,sonicating if necessary.Dilute with water to volume,and mix.Transfer 4.0mLof this solution to the Extraction column,wash with 10mLof water,and discard the eluate.Elute the column with 2mLof methanol,and collect the eluate in a suitable vial.
Standard solution
Transfer about 0.1g of
USP Powdered Asian Ginseng Extract RS,accurately weighed,to a 5-mLvolumetric flask,and proceed as directed for
Test solution,beginning with dissolve in water.
Developing solvent system:
a mixture of chloroform,methanol,and water (65:35:10).Use the lower phase.
Spray reagent:
a mixture of alcohol,acetic anhydride,and sulfuric acid (18:1:1).
Procedure
Proceed as directed in the chapter.Saturate the chamber with
Developing solvent systemfor 2hours.Spray with
Spray reagent,and heat in an oven at 105

for 10minutes.Immediately examine the plate in white light:the chromatogram of the
Test solutionexhibits,among other spots,eight brown-violet spots at the
RFvalues of about 0.70,0.60,0.50,0.36,0.30,0.28,0.20,and 0.18,corresponding in color and
RFvalues to those obtained in the chromatogram of the
Standard solution.