Research of laser induced fluorescence detection system for microfluidic chip

Microfluidic chip is used for the biochemical analyses such as DNA sequencing and the separation of the protein or single cell. It has been shown to offer more advantages than the conventional capillary electrophoresis (CE): less reagent, miniaturization, high efficiency and sensitivity. In this paper, a laser induced fluorescence (LIF) detection system based on a 488nm argon ion laser and FITC fluorescent dye, is described for use with the microfluidic chip. The optical path of transmission type is adopted in our experiment. The pinhole is also applied to improve the performance of the whole detection system. There are some factors that influence the signal-to-noise ratio (SNR) of the detection system such as objective lens, the laser intensity and the pinhole. The pinhole plays a vital role in the confocal system and its performance is discussed in detail in our paper. The experimental data are presented and explained to show the relationships of these factors.