[Fluorescence detection in capillary electrophoresis: detector cell]

A newly developed fluorescence detector cell for capillary electrophoresis was described. Detection of analytes having fluorescence is performed in an on-capillary mode with a xenon are lamp. A grating monochromator was used for the selection of the excitation wavelength. Fluorescence emission was monitored by collection of light from the capillary using a newly devised detector cell positioned at right angle to the excitation beam. Emission wavelengths were isolated using a filter and amplified with a photomultiplier. The detection limits obtained using the newly devised detector cell for amino acids and carbohydrates labeled with a fluorescent reagent were compared with that obtained using a conventional quartz detector cell. The results indicated that 100 nM and 4 microM of amino acids and oligosaccharides labeled with 9-fluorenymethyl chloro-formate and 2-aminopyridine, respectively, could be detected with the newly devised detector cell, in contrast to no signals with the conventional quartz detector cell. The separation and detection of fluorescent derivatives of amino acids, peptides, monosaccharides and oligosaccharides were also performed and an appropriate linearity was observed in a detector response of the samples within the constant concentration.