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

Tamoxifen and its metabolites were separated using a non-aqueous mobil e phase consisting of ammonium acetate and a mixture of organic solven ts, namely, methanol and acetonitrile. The effects of using other orga nic salts as the conducting medium and varying the composition of the mixture of acetonitrile and methanol on the separation were also inves tigated. Optimum separation was obtained by using 25 mM ammonium aceta te in a 50:50 acetonitrile/methanol mixture. High efficiency separatio ns and short analysis times of less than 8 min were obtained. The repr oducibility of migration time was better than 0.4%. The detection limi ts of tamoxifen and its metabolites were less than 40 pg.