Miniaturized Detection System for Fluorescence and Absorbance Measurements in Chromatographic Applications

We present a microoptical detection unit for both laser-induced fluorescence and absorbance analysis on fused silica capillaries, which can be used for chromatographic applications. The detection system is designed by means of nonsequential ray tracing simulations and prototyped by means of deep proton writing. In a proof-of-concept demonstration, the microoptical unit is used for the detection of various concentrations of coumarin dyes. The detection limit ($\hbox{SNR} = \hbox{3.3}$) achieved measures 0.6 nM for fluorescence analysis and 12 $\mu$M for absorbance measurements in capillaries with an inner diameter of 150 $\mu$m.