To begin, weigh three grams of Rhodiola crenulata powder and transfer it into a 100-milliliter conical bottle. Using a large bowl pipette, add 25 milliliters of methanol into the bottle. Place the bottle in the ultrasonic instrument.
Set the power to 250 watts, frequency to 40 kilohertz, time to 30 minutes, and start the ultrasonication. Next, rinse the outside of the bottle under running water until it reaches room temperature. Filter the solution through a 0.22-micron microporus membrane.
Using a one-milliliter syringe, aspirate 800 microliters of liquid from the bottle and collect 400 microliters of the midstream solution into a chromatographic sample bottle. Measure and add one milligram of salidroside, 0.5 milligrams of tyrosol, and 0.5 milligrams of gallic acid into three separate one-milliliter volumetric flasks. Then, fill each flask to the scale marked with methanol.
Sonicate the samples in the ultrasonic instrument using the conditions described previously. Following ultrasonication, aspirate 800 microliters of liquid from the flask. Filter the solution through a 0.22-micrometer microporous membrane and collect 400 microliters of filtrate into the bottle.
Add trichloromethane, ethyl acetate, methanol, and formic acid on one side of the double tank chromatography cylinder. Shake the cylinder to mix the contents evenly and cover the upper cylinder head. Arrange the gallic acid, salidroside, tyrosol standard solutions, and our crenulata solution on the sample rack in positions A1 to A4.Place a 5x10-centimeter silicone sheet on the sampling table.
Turn on the automatic sampling machine and open the air control valve. Press the Continue button for automatic sampling. After sampling, turn off the machine and air valve.
Remove the silicone sheet from the machine. Put the silicone sheet into the other side of the double tank chromatography cylinder. Cover the upper cylinder head and pre-saturate for 20 minutes.
Next, use a tweezer to hold the upper end of the thin layer plate and quickly put the silicone sheet into the development agent. Once the organic solvent evaporates, spray the silicone sheet with chromogenic solution. The thin layer chromatographic analysis showed that the R.crenulata sample appeared in spots of the same color, corresponding to the gallic acid, salidroside, and tyrosol standards.
