SEPARATION OF TAMOXIFEN AND METABOLITES BY CAPILLARY ELECTROPHORESIS WITH NONAQUEOUS BUFFER SYSTEM

Tamoxifen and its metabolites were separated using a non-aqueous mobile phase consisting of ammonium acetate and a mixture of organic solvents, namely, methanol and acetonitrile. The effects of using other organic salts as the conducting medium and varying the composition of the mixture of acetonitrile and methanol on the separation were also investigated. Optimum separation was obtained by using 25 mM ammonium acetate in a 50:50 acetonitrile/methanol mixture. High efficiency separations and short analysis times of less than 8 min were obtained. The reproducibility of migration time was better than 0.4%. The detection limits of tamoxifen and its metabolites were less than 40 pg.