USE OF THE POWELL METHOD TO OPTIMIZE THE COMPOSITION OF HPLC MOBILE PHASE THE SEPARATION OF EPHEDRINE AND PSEUDOEPHEDRINE

The isomers ephedrine and pseudoephdrine are difficult to be separated by HPLC. In this paper, the Powell method was successfully introduced to optimize the composition of mobile phase in HPLC. On a μ Bondapak C₁₈ column (8～10μm, 3.9mm×30cm), KH₂PO₄ solution methanol mobile phase system was optimized forseparating ephedrine and pseudoephedrine by the Powell method. The optimized composition of the mobile phase was found as: 0.01mol/L KH₂ PO₄—MeOH=94: 6 (V/V). The Powell method was carried out in a process illustrated by tables and figures and 0.95 peak separation function was achieved.