Development Of Fluorescence Dissolved Oxygen Sensor

Dissolved Oxygen?DO?refers to molecular oxygen dissolved in water.Quantity of DO is one of the important indicators for water quality.Traditional fluorescent DO sensor is expensive,and the sensing membrane technology is immature and mainly depends on imports.In this paper,the preparation technology of oxygen sensing membrane and the design and implementation of DO sensor are studied.Firstly,The research status of DO sensors at home and abroad is summerized by reviewing a large number of literature.Based on the review,the process of fluorescence generation and quenching were analyzed,the principle of fluorescence quenching and the detection method of DO concentration were studied.Secondly,the preparation technology of fluorescent sensing membrane was explored.DO sensing membranes were prepared by pouring,which used Ru?dpp?₃Cl₂ as fluorescent indicator,cellulose acetate?CA?as matrix material,absolute ethanol as solvent and acetone as dispersant.The effects of solvent and fluorescent indicator on the fluorescence spectrum of oxygen sensing membrane were demonstrated experimentally to obtain the optimal ratio for preparation of DO sensing membrane.Thirdly,the DO sensor is designed and assembled.The angle between the excitation light transmission direction and the fluorescence receiving direction is designed to be 90°in spatial structure,and optical filters are inserted to degrade the effect of spatial stray light.The space optical path of dissolved oxygen sensor is designed and optical components are assembled.Finally,the performance of DO sensor was tested experimentally.The YSI dissolved oxygen sensor was used as the standard to calibrate the sensor,and the repeatability,stability and response time of the sensor were tested.The effects of temperature,PH,salinity and turbidity on DO sensors were studied experimentally,and a correction compensation model was proposed.