Research On Aflatoxin Detection Method Based On Magnetic Signal

The content of aflatoxin in food is strictly restricted due to the wide range of contamination and high toxicity.Existing high-performance liquid phase and other fluorescent quantitative detection methods have the disadvantages of complicated operation,long detection cycle and high cost,which cannot meet the increasing detection.need.This paper presents a novel aflatoxin detection method based on magnetic signals.Magnetic nanoparticles(MNPs)with surface-modified antibodies are used as markers to prepare magnetic chromatography test paper.MNPs are excited under an external excitation magnetic field to generate response signals and use TMR sensors Detect its magnetic signal to achieve rapid quantitative detection of aflatoxin B1(AFB1).The main research contents of this article are:Firstly,the biochemical reaction model is established by combining the magnetic chromatography test paper reaction principle and hydrodynamic equations,and the mathematical model of magnetic signal detection is established according to the linear magnetic dipole theory,and the COMSOL software is used for simulation.In the simulation,three different uniform magnetic field excitation sources are compared to determine the best excitation element for the experiment.The relationship of magnetic signal with position,reaction time and sample concentration was analyzed,and the excitation current and lift-off distance were optimized.Second,use superparamagnetic nanoparticles(MNPs)to prepare magnetic chromatography test paper,build a system hardware platform,use a C-type electromagnet to provide an excitation magnetic field,and detect the magnetic signal of the MNPs on the T line and C line of the chromatography test paper through a TMR sensor.Use LabVIEW to write the host computer software,construct a simple and intuitive human-computer interaction interface,and realize the reception and storage of the collected signals.Finally,the wavelet transform noise reduction technology is used to filter the collected original magnetic signal to remove noise and "burr".Use the least square method to correctthe baseline to solve the problem of baseline drift in the signal waveform.Extract the characteristic T/C value of magnetic signal,draw a standard curve according to the change trend of T/C value with the concentration of AFB1,realize quantitative detection of AFB1,and evaluate the accuracy and repeatability of the detection system.The research results show that the designed detection system can complete a scan in only 40 seconds,greatly reducing the detection time;the magnetic signal detection waveform is basically consistent with the simulation results,proving the feasibility of the experiment;the wavelet transform noise reduction technology effectively reduces the signal noise Realized signal smoothing;least square method solves the problem of baseline drift and improves the reliability of data;the standard curve has good linearity between 0.01 ug /mL—10ug / mL,and the detection limit is 0.008 ug / mL.The designed detection system has good accuracy and repeatability.