High-sensitivity fluorescence detector fluorescein isothiocyanate derivatives of amino acids separated by capillary zone electrophoresis.
A fluorescence detector has been developed for capillary zone electrophoresis that produces a ten-fold improvement in precision compared with the previous state-of-the-art in fluorescence detection. This instrument, which is based on a sheath-flow cuvette flow chamber and a 0.05-W argon ion laser beam, combines a high numerical aperture collection optic, N.A = 0.65, with a high quantum yield photomultiplier tube, phi approximately = 0.15 at the wavelength of maximum emission. Detection limits (3 sigma) range from the injection of 1.7 . 10(-21) mol (1.3 . 10(-12) M) of fluorescein isothiocyanate (FITC)-labeled arginine, the best case, to 6 . 10(-21) mol (5.6 . 10(-12) M) of FITC-cysteine, the worse case. Signal linearity extends for at least five orders of magnitude from the detection limit to greater than 10(-16) mol (10(-7) M) injected.
Wu
S
S
Department of Chemistry, University of Alberta, Canada.
Dovichi
N J
NJ
D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry*; D007834:Lasers; D008433:Mathematics
D000596:Amino Acids; D016650:Fluorescein-5-isothiocyanate