A:
Thin-Layer Chromatographic Identification Test 201
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 L1 with a sorbent mass to column volume ratio of 360 mg per 0.85 mL, or equivalent. Condition the column prior to use by washing with 3 mL of methanol and with 8 mL of water.
Test solution
Transfer about 1.0 g of Powdered Extract, accurately weighed, to a 25-mL volumetric flask, and dissolve in water, sonicating if necessary. Dilute with water to volume, and mix. Transfer 4.0 mL of this solution to the Extraction column, wash with 10 mL of water, and discard the eluate. Elute the column with 2 mL of methanol, and collect the eluate in a suitable vial.
Standard solution
Transfer about 0.1 g of
USP Powdered Asian Ginseng Extract RS, accurately weighed, to a 5-mL volumetric 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 system for 2 hours. Spray with
Spray reagent, and heat in an oven at 105
for 10 minutes. Immediately examine the plate in white light: the chromatogram of the
Test solution exhibits, among other spots, eight brown-violet spots at the
RF values of about 0.70, 0.60, 0.50, 0.36, 0.30, 0.28, 0.20, and 0.18, corresponding in color and
RF values to those obtained in the chromatogram of the
Standard solution.