Solubility Analysis

　　1 Preparation

　　1.1 Open the water bath and set the temperature to 37°C (pay attention to whether the water level in the water bath is above the minimum required water level);

　　1.2 Use DMSO to prepare the compound into a stock solution with a concentration of 10 mg/mL (if the compound is not dissolved, the concentration can be reduced to allow the compound to dissolve) and set aside;

　　1.3 Reasonably design the paper typesetting and computer typesetting of the experiment (samples with low concentration are ranked first);

　　2 Experimental steps

　　2.1 Take 5µL stock solution + 495µL Buffer (select Buffers with different pH levels according to experimental requirements: pH=7.4/ pH=6.5/ pH=5.0/ pH=2.0/70%ACN), dilute 100 times to 100µg/mL, and need to be reconstituted. hole;

　　2.2 T0: Take 5µL stock solution + 495µL DMSO, duplicate holes are required;

　　2.3 Place in a water bath and shake well for 120 minutes;

　　2.4 After the shaking time is over, centrifuge at 4000 rpm and 37°C for 20 minutes;

　　2.5 Take the supernatant and dilute the sample 100 times to 1µg/mL with internal standard acetonitrile;

　　2.6 Inject samples in LC MS/MS.