Research On Detection Method Of Four Animal-derived Food Safety Hazards Based On Quantum Dot Fluorescent Probe

As the improvement of the quality of life of residents,the percentage of animal-derived foods in people's diets has gradually increased.Therefore,it is important to ensure the quality and safety of animal-derived foods.In this study,four hazard factors(including nitrite,clenbuterol,tetracycline and biogenic amines)in animal-derived foods were used as the research objects,and the unique advantages of fluorescent quantum dots were used to establish specific fluorescence detection methods for hazard factors in animal-derived foods.(1)Blue fluorescent carbon quantum dots were synthesized via one-step hydrothermal method.Utilizing the redox reaction between nitrite(NO₂^-)and ferrous ion(Fe²⁺)and the fluorescence quenching effect of ferric ion(Fe³⁺),a“turn on”fluorescent probe for NO₂^-was constructed.The quenching intensity was linearly associated with the NO₂^-concentration ranged from 10 to 400?M(R²=0.996),and the limit of detection was 0.48?M.Furthermore,various potential additives did not interfere with the detection signal.In the analysis experiment of NO₂^-in sausage samples,the detection results of the proposed probe were basically consistent with those of ion chromatography,indicating the accuracy and reliability of the proposed probe.(2)Aiming at the illegal additive clenbuterol(CLB)in meat products,a ratiometric fluorescent probe based on graphene quantum dots@pyridine ruthenium(GQDs@[Ru(bpy)₃]²⁺)was constructed.The GQDs prepared via the bottom-up synthesis method emitted yellow-green fluorescence,and the fluorescence could be quenched by CLB through the diazo coupling reaction.While[Ru(bpy)₃]²⁺with red fluorescence was used as a reference signal,its fluorescence was almost unaffected by CLB.There was a linear relationship between the intensity ratio of the two fluorescence signals and the CLB concentration ranged from 0.05 to 40?M,accompanied by a fluorescence change from yellow to red.The detection limit was 0.029?M,and the recovery rate of the actual sample was satisfactory.(3)Antimonene quantum dots(AMQDs)with excellent luminescence properties were prepared by the ultrasonic-assisted liquid phase exfoliation method.Under acidic conditions,the blue fluorescence of AMQDs was quenched by tetracycline(TET)via the internal filtration effect,and at the same time,due to the enhancement effect of the solvent on the inherent fluorescence of TET,striking red fluorescence was produced.The intensity ratio of the two emission peaks was linearly correlated with the TET concentration in the range of 0.1-150?M,and the detection limit was 0.027?M.Under alkaline conditions,based on the internal filtration effect and dynamic quenching principle,the fluorescence of AMQDs was quenched,and yellow-green fluorescence was generated due to the decomposition of TET.The two fluorescence signal intensity ratios were linearly correlated with the TET concentration in the range of 0.1-10?M and 20-80?M,and the limit of detection reached 0.074?M.In the spike-recovery test of animal-derived food,the recovery rates under the two p H conditions were between 90-110%,reflecting that the probe possessed good practical application potential.(4)Since many fluorescent materials are prone to aggregation-induced quenching in the solid phase,this study used a one-step hydrothermal method to prepare red fluorescent quantum dots with aggregation-induced emission characteristics.Combining with the fluorescence enhancement effect caused by the conformational changes before and after the reaction between fluorescein and amine substances,the quantum dots and fluorescein were jointly modified on the filter membrane by physical deposition.Under ultraviolet light,the composite film emitted pink fluorescence.When ammonia gas was present,the green fluorescence of fluorescein increased due to conformational changes,and the color of the composite film changed from pink to bright green.The color change can be observed within 1 min,and the reusability was good.In the biogenic amines detection experiment of shrimps and crabs,the prepared membrane showed good color response at three different temperatures,suggesting that it could be used for the detection of biogenic amines of animal-derived foods.