Bioanalysis of some anthracyclines in human plasma by capillary electrophoresis with laser-induced fluorescence detection.

A rapid method for the determination of daunorubicin, doxorubicin and epirubicin in human plasma is described. Samples are pretreated and concentrated by liquid-liquid extraction with chloroform and back-extraction into phosphoric acid, respectively. This pretreatment results in a sample matrix of low ionic strength in comparison with the electrophoresis buffer, permitting a 20-30-fold increase in the injected amount by zone sharpening when electrokinetic injection is applied. Analyte interaction with the capillary wall is prevented by using high acetonitrile contents in the electrophoresis buffer, which results in reproducible migration times and highly efficient separations. Laser-induced fluorescence detection provides an extremely sensitive and selective method without detectable biological interferences. The limit of determination of daunorubicin, epirubicin and doxorubicin in plasma ranges from 125 to 250 pg/ml.