The relevant substance is taken in an appropriate amount, accurately weighed, dissolved and diluted with methanol to prepare a solution containing about 1 mg per 1 ml. As a test solution, accurately measure 1 ml, place it in a 50 ml volumetric flask, and dilute to the mark with methanol. Shake well as a control solution. According to the chromatographic conditions under the content determination, 10 μl of the control solution was injected into the liquid chromatograph to adjust the detection sensitivity so that the peak height of the main component reached 50% of the full scale of the recorder. Then, 10 μl of each of the test solution and the control solution were accurately weighed and injected into a liquid chromatograph, and the chromatogram was recorded until the retention time of the main component peak was 1.5 times.
If there are impurity peaks in the chromatogram of the test solution, no more than one. The peak area should not be greater than 3/4 of the main peak area of the control solution. Take the weight loss of the product and dry it to constant weight at 105 °C. The weight loss should not exceed 0.5% (Appendix VIIIL).