Sensitive determination of ephedrine and norephedrine inhuman plasma samples using derivatization with 9-fluorenylemthyl chloroformate and liquid chromatography

摘要

A high-performance liquid chromatography procedure for the determination of ephedrine and norephedrine using luorimetric detection in plasma samples is described. A double liquid—liquid extraction was performed, followed by derivatization with 9-fluorenylmethyl chloroformate. The extracts were chromatographed with a 5-p~m C1 ~ (I 50X4.6 mm LD.) column using a mobile phase composed of acetonitrile and water (52:48; vlv). The excitation and emission wavelengths were respectively 264 nm and 313 nm. Calibration curves were linear over the range 0 to 300 ng/ml for each analyte. The specificity of the method was demonstrated with several FMOC-reacting drugs. The limits of quantification are similar to those obtained with the reference method: 2 ng/ml for ephedrine and 5 ng/ml for norephedrine. This method has been successfully applied to the determination of ephedrine and norephedrine plasma levels after administration of low doses of ephedrine to healthy subjects.