The Detection Study Of Aflatoxin B1 In Grain Based On Fiber Sensor

Aflatoxin(AFT),a carcinogenic and immunosuppressive secondary metabolite produced by Aspergillus flavus and Aspergillus parasiticus,be c ome s a pa rtic ula r c onc e rn a s food c onta mina te s.AFT is found widely in food and feed,such as peanuts,nuts,corn,and grains.Among the several kinds of AFT,aflatoxin B1(AFB₁)is considered to be the most toxic and the most pote nt he pa toc a rc inoge n,re c ognize d a s group I c a rc inoge n.Once the food contaminated with AFB₁ a re e a te n by huma n a nd a nima ls,it will provide a thre a t to he a lth.Therefore,a method for detecting AFB₁ with high sensitivity has become the research direction.Accurate and timely detection of AFB₁ will help reduce food safety issues and better protect people's safety.Based on the advantages of high sensitivity,anti-interference and simple structure,optical fiber sensing technology has been rapidly developed.In the paper,the detection study of aflatoxin B1 in grain based on fiber sensor have been proposed.The main contents are shown as following:1.A sensor based on hollow-core photonic crystal fiber was proposed to realize the fluorescence detection of AFB₁.The distribution of optical field energy and transmission loss of the sensor structure are simulated theoretically by COMSOL Multiphysics software,which proves the feasibility of the sensor.Two sets of different experimental systems for UV irradiation were proposed.The first set was to use a UV lamp with a center wavelength of 370 nm to il uminate the sensor from the side to excite the AFB₁ fluorescence signal,and achieve AFB₁ measurement in the concentration range of 100?1000 ng/ml with a detection limit of 14.97 ng/ml.The second system was improved on the basis of the first system.Using an ultraviolet LED lamp with a center wavelength of 340 nm,the sensor was il uminated from the end face of the fiber,and the AFB₁ fluorescence signal was triggered in the concentration range of 25?800 ng/ml.By changing the length of the sensor,the detection concentration can reach 1ng/ml,and the detection limit is up to 1.34ng/ml.In addition,the sensor has high sensitivity,simple structure,easy fabrication,which can be applied to actual biological detection.2.A coreless fiber based SPR sensor was proposed to achieve the concentration measurement of AFB₁.At the same time,the sensor was used to measure the refractive index in the range of 1.3335-1.4297.With the increase of SRI,the resonance wavelength is red-shifted.The highest sensitivity of SRI is 4328.2 nm/RIU,and the average refractive index sensitivity is 2836 nm/RIU.The response time of the sensor is?15s,and the stability is good.Based on this experiment,the AFB₁ was experimentally measured using this highly sensitive sensor.In the AFB₁concentration range of 1?5?g/ml,the resonance wavelength increases linearly toward the longer wavelength as the AFB₁ concentration increases.The sensitivity of AFB₁ is2.1nm/(?g/ml)with the range from 1?g/ml to 5?g/ml and the precision can reach0.16?g/ml.In terms of its performance,the SPR sensor has the advantages of miniaturization,high sensitivity and good stability.