Determination of fluoxetine and norfluoxetine in human plasma by capillary gas chromatography with electron-capture detection

Abstract

A capillary gas chromatographic method with 63Ni electron-capture detection is reported for the determination of fluoxetine (Prozac) and its metabolite norfluoxetine in human plasma. A liquid—liquid extraction is used, followed by derivatization with heptafluorobutyric anhydride to increase the sensitivity of detection. A 30 m × 0.25 mm I.D. DB-17 capillary column resolves the compounds from endogenous matrix interferences. The limit of quantitation by this method is 5 ng/ml for each compound. Stability studies show that fluoxetine and norfluoxetine are stable in human plasma for up to 96 h at room temperature and up to one year at −20°C.