Wavelength-resolved fluorescence detector for microchip capillary electrophoresis separations

In this work, the detector system is applied to the capillary electrophoretic microchip separation of three rhodamines and their impurities (excitation: 450-490 nm; emission: >500 nm). Complete emission spectra of submicromolar solutions are recorded on-line. Comparable with diode-array detection in UV/vis-spectroscopy, this detector set-up yields information-rich electropherograms. The additional dimension of information compared to standard fluorescence detection systems enables peak assignment by means of fluorescent properties of the analytes and the immediate detection of coelutions due to a change of signal ratios at chosen wavelengths (peak purity plots).