Take the sample, add chloroform methanol (1:1) to prepare a solution containing 10mg per 1mL as the test solution; Accurately measure an appropriate amount of the solution and add chloroform methanol (1:1) to dilute it to 25% per 1mL μ G solution as the control solution. Test according to thin layer chromatography (Appendix Ⅴ B), and suck 50% of the above solutions μ 50. Dot respectively on the same silica gel G thin layer plate, use n-hexane chloroform methanol (54:28:18) as the developing agent, and put a small beaker containing 5mL of concentrated ammonia solution in the developing cylinder. After developing, dry it in the air, and color it in iodine vapor. If the test solution shows impurity spots, they should not be deeper than those of the control solution.
Loss on drying
Take the product and dry it to constant weight at 105 ℃. The weight loss shall not exceed 0.5% (Appendix VIII L).
Ignition residue
It shall not exceed 0.2% (Appendix Ⅷ N).