Preparation of nanopaticles of SCF-CO2 extraction of Magnolia officinalis.

Objective:To prepare nano-particles of SCF-CO2 extraction of Magnolia officinalis with rapid expansion of supercritical solution(RESS) and optimize the preparation procedure with orthogonal experiment.Method:The preparation procedures were optimized by orthogonal test L(934) with the mean particle size and the amounts of total-phenol as indexes.Factors of the extraction pressure and temperature,diameter of nozzle,pre-expansion temperature were evaluated for their effects on preparation process.Result:The optimal preparation technology was as follows:the pressure was at 25 MPa and temperature was at 50 ℃,the diameter of nozzle was 200 μm,the pre-expansion temperature was at 30 ℃.The nano-particles solution was settled,of which the average particle size was 303.50 nm and the total-phenol contents was 0.091 g·L-1,and the stability of the particle size kept well after 1 month of storage at low temperature and obturation the mean particle size.Conclusion:The RESS method is applicable for preparing nanoparticles solution of SCF-CO2 extraction of M.officinalis at low operating temperature.It is simple processing,and no environmental pollution,and no residual solvent.