SEPARATION OF FORMOTEROL ENANTIOMERS AND DETECTION OF ZEPTOMOLAR AMOUNTS BY CAPILLARY ELECTROPHORESIS USING LASER-INDUCED FLUORESCENCE

A sensitive and rapid high-performance capillary electrophoresis (HPCE) method combined with laser-induced fluorescence (LIF) detection is described, which is suitable for the analysis of racemic formoterol and formoterol enantiomers after derivatization with fluorescein isothiocyanate (FITC). The limit of detection is 1 pg/ml in the case of FITC-derivatized racemic formoterol in the absence of chiral selector. Upon injection of 5 nl, it corresponds to an amount of not more than 120 molecules. The chiral recognition occurs in the presence of heptakis(2,3,6-tri-O-methyl-beta-cyclodextrin) as a chiral selector in the buffer electrolyte and yields a detection limit of 10 . 10(-12) g/ml for each enantiomer.