Study On The Detection Of Food Additives Based On Gel-Solid Phase Microextraction And Fluorescence

In today's increasingly prominent food safety and environmental safety issues,the large-scale use of food additives has caused widespread concern in society.The key to solving these food safety problems is to propose a technology that can conveniently and quickly detect food additives.The traditional detection technology is limited in practical application due to the need for large-scale instruments and equipment,as well as the complex operation and long time consuming.Therefore,this paper proposes a gel-based flexible substrate,using solid-phase micro-extraction theory,combined with solid-phase fluorescence technology,rapid,non-destructive detection of food additives,can be applied to a variety of food additives on-site analysis and research.In this study,a flexible gel substrate was prepared by mixing high molecular weight polyvinyl alcohol(PVA)with a crosslinking agent sodium tetraborate.In order to maximize the extraction efficiency of PVA gel,the factors affecting the flow properties and viscoelastic properties of the gel matrix are fully considered in this paper.The PVA mass fraction,the solvent ratio of PVA solution,and the ratio of PVA solution to sodium tetraborate are determined.The optimal conditions for the preparation of the gel are as follows: a mass fraction of 4% of the PVA solution with the ethanol solvent ratio of 60%,and a mass fraction of 4% tetraborate sodium solution,and a mixture ratio of PVA solution and sodium tetraborate solution 10:9.At the same time,using the food additives Rhodamine B and auramine O as the probe molecules,the limit of detection of the two additives was tested.The detection limit of rhodamine B was 0.01 mg/L.The detection of auramine O was found and the limit is 0.1 mg/L.In this paper,basing on the optimal gel determination,the real sample detection in the field of food and Chinese herbal medicine is carried out by using gel solid-phase micro-extraction fluorescence detection technology.In the food field,this study tested the market for chili powder,plum,and sausage.In the test process,the actual sample was spiked using the soaking method.By repeatedly wiping the surface of the sample with a gel and fluorescence testing the gel,it was found that the minimum detection limits of rhodamine B in the gel for paprika powder,prunes,and sausages were 7 mg/kg,3 mg/kg,and 0.5 mg/kg,respectively.In the field of Chinese herbal medicines,this article tested the common Chinese herbs Puhuang,Corydalis yanhusuo and Phellodendron chinense using auramine O as the test object.The three kinds of samples were spiked first,and then the auramine O was extracted by repeatedly rubbing the surface of the sample with a gel.The solid phase fluorescence technique was used as a detection method.Finally,the fluorescent signal of auramine O was detected in all three samples.And the detection limit of the auramine O in Puhuang,Corydalis,and Phellodendron amurense were 15 mg/kg,3.28 mg/kg and 7.78 mg/kg,respectively.In this study,after the preparation of a flexible gel substrate,the preparation conditions were optimized,and the detection of illegal additives in foods and medicines was initially achieved,thereby realizing the application of gel solid-phase micro-extraction fluorescence technology in the food field.The application of solid-phase micro-extraction fluorometry has opened up new fields.