Confocal Laser Induced Fluorescence Detector

It is possible to integrate the process of the separation, reaction for the biochemical samples with the microfluidic analysis system. The process is fast and the samples are high throughput and low consumption. Nano channels are embedded into the microfluidic chips improving further the analysis ability of the chips. One or a several parameters are tested in the process of the sample analysis. So the detector used for the microfluidic chips is an indispensable part of the process. There are optical detector, electrochemical detector, mass spectrometry detector and other detector according to the detection principle. Optical detector and electrochemical detector are the most extensive application. Laser induced fluorescence, chemical luminescence and ultraviolet absorption detector and other optical detector are still the mainstream means. Now laser induced fluorescence detection is one of the most sensitive detection methods. At present the main research samples for the microfluidic chips, nucleic acid, protein and amino acids are stimulated to eradiate fluorescence or stimulated to eradiate fluorescence through the derivative. So in the process of the microfluidic chips application, the position laser induced fluorescence detector is very important.In this paper, according to the principle of laser induced fluorescence detection and the technology of the confocal, a confocal laser induced detection is assembled which is used for the microfluidic chips. The detector is constituted dichroic mirror, lens, photomultiplier tubes, pinhole and other elements. In the process of the detector assemble, the problem of the pinhole position adjustment and light path adjustment are solved. Objective focus and pinhole are in conjugate position. So the light that is not from the focal plane can’t be through the pinhole and the background noise is reduced.In this paper, the chip with micro channels and the chip with nano channels are make and the two chips are assembled and bonded in the high temperature. Using NMM-1， the shape of the nano channels are tested. The uniformity of the different nano channels’depth and width in the same chip is calculated. The application measurement is conducted with the glass micro-nanofluidic chip and the fluorescence sample is the FITC reagent. A series of the FITC’s signal is measured from10μmol/L to200nmol/L. The relationship between concentration and fluorescence signal is tested in the case of low fluorescence concentration.