A.3Preparation of testA.3.1Preparat

A.3Preparation of testA.3.1Preparation for reference solution Curcumin, demethoxycurcumin and double demethoxycurcumin controls are taken as appropriate amounts, and methanol is added to make a mixed control containing 0.5mg per 1ml.A.3.2Preparation for sample solution The ground sample (through a 60-mesh sieve) 0.2g is placed in a corked conical bottle, and 50 mL methanol is added to determine the mass. After ultrasonic treatment (power: 250w, frequency: 40khz) for 45 min, the mass is cooled down, and then determined. The lost mass is supplemented with methanol, shaken well, and the supernatant is filtered with microporous filter membrane (0.45nm).A.4Procedure of measurementThe reference solution and the sample solution are precisely extracted with 10 l each and injected into the liquid chromatograph for determination