Design And Development Of A Portable Fluorescence Spectrometer For The Detection Of Antibiotic Residues

Antibiotics have been widely used in the prevention and treatment of epidemic diseases in humans and animals since they were discovered.With their heavy use,they have entered various media in the environment,greatly threatening human life and health,so it is necessary to detect the residual antibiotics in the environment.Fluorescence analysis is becoming an important technical tool for antibiotic detection because of its low detection limit,high selectivity,low demand for test samples and simple sample preparation method.Fluorescence spectrometers combined with fluorescence analysis methods cannot meet the demand for miniaturization and portability in environmental monitoring applications due to their large size.Therefore,a fluorescence probe was prepared as a detection reagent and combined with the portable fluorescence spectrometer with STM32F103VRT6 as a control core to achieve the detection of doxycycline(DOX)residues in the environment.This paper firstly introduces the origin,current use and pollution hazards of antibiotics,and then describes the measurement principle,instrument structure and development status of fluorescence spectrometer.Next,a fluorescence probe based on boron-dipyrromethene(BODIPY)was prepared,which can produce specific fluorescence response with DOX.Finally,the system composition and design framework of the portable fluorescence spectrometer was proposed,which uses UV LED lamp as the light source,grating as the monochromator,photomultiplier tube as the detector,and a stepper motor to directly drive the grating to achieve wavelength scanning.The main tasks include:1.The parameters and performance of fluorescence spectrometer products at home and abroad were analyzed,and combined with the design objectives,the overall design framework of the portable fluorescence spectrometer was proposed.The system has a compact and reasonable structure,reduces the noise interference in the optical system,and improves the measurement accuracy of the instrument.2.The fluorescence probe based on BODIPY was prepared to realize the detection of DOX,and the UV-Vis absorption spectrum,fluorescence spectrum and detection limit of the probe were characterized,the mechanism of the interaction between the probe and DOX was investigated,which provide the basis for the design of portable fluorescence spectrometer.3.The optical path structure of conventional fluorescence spectrometers was analysed,and the optics were selected and the optical structure was improved according to the physicochemical properties of the detection reagents,combined with the design objectives and functional requirements.4.An ARM Cortex-M3-based embedded microprocessor,the STM32F103VET6,was selected as the system control core to achieve control of the entire measurement process of the instrument.It also introduced the design of the instrument’s hardware circuit modules,including the processor peripheral circuit,the power supply module circuit,the motor drive module circuit,and the digital signal acquisition module circuit.5.By comparing the three commonly used grating control structures,sine,cosine and cam,the control method of wavelength scanning by stepper motors directly driving the grating was proposed.The grating turntable was then designed,the stepper motor and drive module,the digital signal acquisition module were tested and the housing for the portable fluorescence spectrometer was designed.