Study On Optical Fiber Sensing Detection Of Doxycycline Drug Residues

As a broad-spectrum antibiotic,doxycycline is widely used in the prevention and treatment of bacterial infections in livestock and poultry.However,the abuse of doxycycline will lead to its residues in water and animals.After human consumption,it will pose a threat to human health.Therefore,the detection of doxycycline residues in food in people ’s daily life is imminent.So far,there are many methods for the detection of doxycycline,such as microbial method,immunoassay and highperformance liquid chromatography.However,these detection methods generally require expensive experimental equipment,high requirements for the experimental environment and long detection time.Therefore,it is of great significance to develop low-cost,real-time detection and short response time detection methods for doxycycline.Based on the Mach-Zehnder interference principle,this paper develops local cone "water drop structure" fiber optic sensor with specific recognition of doxycycline.According to the designed optical fiber structure,the cladding of local cone "water drop structure" fiber optic sensor and the evolution of the optical field mode of the core are simulated.Through theoretical simulation and experimental exploration,the structural parameters of the water droplet structure optical fiber sensor are determined.Local cone "water drop structure" fiber optic sensor has higher refractive index detection sensitivity than the same structure non-taper sensor.The molecularly imprinted polymer film was assembled on the sensor by molecular imprinting technology,and various drugs such as oxytetracycline hydrochloride(OTC),cefalexin(CED),and antipyrine(AP)were compared and tested under laboratory conditions at25 °C.The results showed that when the solution concentration was 0～300 ppm,the detection sensitivity of the sensor to doxycycline was 5-37 times that of other drugs,indicating that the sensor had high detection sensitivity and specificity for doxycycline drug molecules.Finally,the response time and repeatability of the fiber optic sensor were investigated.It was found that the fiber optic sensor with water droplet structure had a response time of 120 s and was stable for doxycycline molecules in solution,and had good repeatability.