OBJECTIVE  To study the regulation rules of ethanol precipitation concentration on chlorogenic acid molecular state and nanofiltration mass transfer behavior in Reduning injection.

  METHODS  Based on the solution-diffusion effect, the regulation rules of chlorogenic acid molecular state and nanofiltration mass transfer behavior were calculated and analyzed by mass transfer mathematical model in ethanol precipitation intermediates of Reduning injection.

  RESULTS  The experiment showed that the nanofiltration mass transfer model was applied to the quantitative analysis of chlorogenic acid in the ethanol precipitation intermediate solution of Reduning injection. The proportion of chlorogenic acid in molecular form ranged from 22.21% to 82.43% when the concentration of ethanol precipitation was between 60% and 80%. With the increase of ethanol concentration, the main existing states of chlorogenic acid gradually changed from ionic state, associative state to molecular state. Meanwhile, the migration degree was 80%>70%>60% of ethanol precipitation concentration, respectively.

  CONCLUSION  The nanofiltration separation behavior of chlorogenic acid in monomer solution, 60% and 70% ethanol precipitation intermediates can be coordinated by the effect of "solution-diffusion and steric hindrance". This study provided a research road for the orderly separation of components in organic solution.