2. Secondly, the samples of dicyandiamide standard solutions A, B, C, D and E with different concentrations were analyzed by HPLC, and the peak area of each dicyandiamide was recorded. The standard curve of dicyandiamide concentration-peak area was drawn by external standard method, and the regression equation of the standard curve was obtained.
3. Finally, prepare a dicyandiamide sample solution, analyze the sample with a high performance liquid chromatograph, record the peak area, and calculate the dicyandiamide content in the solution according to the standard curve regression equation in step.