A method is described for the analysis of the non-steroidal anti-estrogenic antineoplastic agent, tamoxifen and its 4-hydroxy and N-desmethyl metabolites in liver, uterine, fat and human breast tumor tissue, and whole blood, plasma and cerebral spinal fluid. The report focuses on separation of analytes from the biological matrix. After extraction, analytes are converted to fluorescent phenylphenanthrenes, which are separated by reverse phase paired ion chromatography with spectrofluorometric monitoring of column eluent. By control of column temperature, chromatographic analysis time could be significantly reduced and sensitivity increased.