Multi-Wavelength Fluorescence Detection for a High-Throughput CE System under a Spectrum Equipped Diascopic Microscope Configuration

This paper presents a novel method for multi-wavelength fluorescence detection for high-throughput analysis of bio-samples in a micro-CE chip. In general, fluorescent dye can be excited with light sources in a specific wavelengths then the excited fluorescence emits light with longer wavelengths such that a special filter set on a fluorescence microscope is required for this application. Instead of using conventional laser induced fluorescence scheme, this study adopts a diascopic illumination light source for fluorescence excitation and an UV-VIS-NIR spectrometer for emission signals detection. Multiple fluorescence dyes can be excited and detected simultaneously in a single CE channel with this approach. In addition, the proposed system is simple and low-cost since no sophisticated optical filter sets and laser sources are required for the detection purpose. Experimental result shows that the proposed system is feasible for parallel detecting a mixed fluorescence sample in a single run. Fluorescence dyes including Atto 610, Rhodamine B and FITC are successfully detected and identified simultaneously. The LOD (limit of detection) for detecting FITC fluorescence of the proposed system can be as low as 10^-5 M(SNR=5.56) which is applicable for to general bio-analytical applications.