Internal standard method for the measurement of doxorubicin and daunorubicin by capillary electrophoresis with in-column double optical-fiber LED-induced fluorescence detection.

An internal standard method has been developed for the simultaneous determination of anthracycline antibiotics, doxorubicin (DOX) and daunorubicin (DAN), in rabbit plasma using capillary electrophoresis (CE) with in-column double optical-fiber LED-induced fluorescence detection (CE-ICDOF-LED-FLD). Rhodamine B (RhB) was selected as an internal standard because its emission wavelength is similar to that of the anthracycline antibiotics. Parameters including buffer pH, buffer concentration, organic solvents and separation voltage have been investigated to explore the sensitivity and separation efficiency of DOX and DAN. The optimal electrophoretic separation conditions were a borate buffer (15   mM, pH 9.0) containing 50% acetonitrile (v/v), 10   s hydrodynamic injection at a height of 20   cm and a separation voltage of 15   kV. The developed CE-ICDOF-LED-FLD method provides limits of detection of 18 and 13   ng/mL for DOX and DAN in rabbit plasma samples, respectively. The recoveries ranging from 93.7 to 104.8% and the relative standard deviations at 1.1–1.7% were achieved for DOX and DAN in spiked rabbit plasma samples.