Research on anti-interference technology of groundwater heavy metal fluorescence detection device

Heavy metals in liquid seriously harm the environment and threaten human health. The fluorescence detection system based on fluorescence probe method has the advantages of small size and fast detection speed, which is helpful to understand the pollution status and environmental risk of groundwater and provide scientific basis for liquid environment treatment. However, long time laser irradiation of fluorescent probe produces photobleaching phenomenon, which weakens the fluorescence signal intensity. The excitation noise in the confocal detection optical path is high, resulting in low signal-to-noise ratio, which cannot meet the requirement of high sensitivity detection. In this paper, the anti-interference technology of groundwater heavy metal fluorescence detection device is studied. The effect of photobleaching and optical noise is avoided by single pulse excitation and noise reduction using dichroic mirror. After applying the improvement, the repeatability error is reduced from 1.59% to 0.23%, while the noise is reduced by 87.5%. The stability of the detection results and the signal-to-noise ratio are significantly improved, so the anti-interference ability of detection device is greatly enhanced.