A simple light‐emitted diode‐induced fluorescence detector using optical fibers and a charged coupled device for direct and indirect capillary electrophoresis methods

Abstract We constructed a simple fluorescence detector for both direct and indirect CE methods using a blue light‐emitted diode (470 nm) as excitation source, a bifurcated optical fiber as a waveguide, and a CCD camera as a detector. The connection of all the components is fairly easy even for nonexperts and the use of a CCD camera improves the applicability of this detector compared to the others using PMTs because it permits the recording of 2‐D electropherograms or phosphorescence measurements. This detector provides a compact, low cost, and rapid system for the determination of native fluorescence compounds which have high quantum yields by CE with direct fluorescence detection, showing an LOD of 2.6×10 −6 M for fluorescein; the determination of fluorescence derivative compounds by CE with direct fluorescence detection, showing an LOD of 1.6×10 −7 M for FITC‐labeled 1,6‐diaminohexane; and nonfluorescence compounds by CE with indirect fluorescence detection with an LOD of 2.7×10 −6 M for gallic acid.