A novel optical detection system for chromatography applications

Abstract

In this work we describe the design of a confocal microscope based optical system which can be used for two types of miniaturized fluid-chromatographic experiments: first of all for the study of shear-driven fluid separations in microchannels and secondly for the study of peak-broadening phenomena in pressure-driven fluids in the same type of microchannels. For the first type of measurements fluorescing dyes (coumarins) are used while for the latter type photo-active molecules (uncaged dyes) like for example fluorescein molecules are needed. We designed the detection system in such a way that by making some small changes to the system we can swap from one application to the other. After calculating the specifications of the optical components, we simulated the system with the sequential ray-tracing-software Solstis and built the system. Finally we did some preliminary experiments which demonstrated the working principle of our setup.