Fluorescence detector

Abstract

The invention provides a fluorescence detector. The fluorescence detector comprises an excitation light source, an excitation light filter, a first dichroscope, a first converging lens, a detection pool, a curved surface reflector, a second dichroscope, a light trap, an emission light filter and a photoelectric detector, the fluorescence detector adopts a collinear light path structure, fluorescence and unused exciting light are collected and reflected by a curved reflector, and the exciting light and stray light doped in the fluorescence are eliminated through a second dichroscope on a fluorescence emission light path and a light trap behind the second dichroscope. Therefore, on the premise that secondary utilization of the exciting light and efficient collection of the fluorescence are ensured, adverse effects of the exciting light and stray light which are reflected into the fluorescence emission light path by the curved surface reflector on the detection signal-to-noise ratio are avoided, and the detection signal-to-noise ratio can be improved by more than four times.

Description

technical field [0001] The present invention relates to the technical field of optical detection, in particular, to a fluorescence detector. Background technique [0002] Fluorescence detector is a detector with high selectivity and ultra-high sensitivity, which plays an important role in the detection of ultra-trace molecular level. The sensitivity of the detector is one of the important parameters to measure its performance. In order to improve the sensitivity, people usually optimize the fluorescence detector from the perspective of increasing the excitation light intensity and improving the fluorescence collection efficiency. In principle, the fluorescence generated by the excitation region illuminated by the excitation light is spatially divergent, and the detector can only collect the fluorescence at a small part of the angle, so the fluorescence collection efficiency is very low. In order to improve the collection efficiency of fluorescence, people arrange the curved...

AI Technical Summary

Problems solved by technology

However, due to the limited cut-off depth of the filter, it is difficult to avoid stray light entering the photodetector, resulting in enhanced background signal and reduced signal-to-noise ratio. When mirror devices are added to the system, there will be more excitation light It is reflected to the fluorescent light path, so that the addition of mirror-like devices does not significantly improve the overall sensitivity of the system

In order to prevent stray light from entering the fluorescent light path, patent CN109387490A proposes a method of using a two-color coated curved surface mirror instead of a total reflection curved surface mirror, which ensures the fluorescence collection efficiency and prevents the excitation light from being reflected together with the fluorescence. After passing through the sample cell once, it is directly transmitted through, and a considerable part of the "unused" excitation light is lost, which also has a certain adverse effect on the improvement of the signal-to-noise ratio.

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