Development Of Visual Rapid Detection Products For Dimethoate And Ethyl Carbamat

The prevention and monitoring of small molecular hazards in food is the focuses of food safety.Small molecular hazards such as pesticides,antibiotics,biotoxins,and ethyl carbamate in fermented foods are widely present in foods.However,there are still some challenges in the detection of small molecular hazards,and detection methods mostly rely on large-scale instruments.At present,there are no relevant reports on visualized rapid detection products of dimethoate pesticides and ethyl carbamate.In this manuscript,functional nanomaterials were selected as color signals,and small molecular hazards or their nucleic acid aptamers were used to adsorb or wrap functional nanomaterials.Then,a colorimetric sensor of small molecular hazards was constructed,and the visual fast detecting enzyme sheets and test strips were further developed.The main contents of this study are as follows:（1）A colorimetric sensor and a visual rapid detection enzyme sheet for dimethoate pesticide were constructed.Silver citrate（Ag Cit）mimics lassase activity and catalyzes2,4-dichlorophenol（2,4-DP）to form quinone,which combines with 4-amino-antipyrine（4-AAP）to form a red substance.Dimethoate can inhibit the lassase-like activity of the simulated enzyme silver citrate（Ag Cit）,making the color of the colorimetric sensing solution change from red to colorless,so as to construct a sensitive colorimetric sensor for dimethoate pesticide.Moreover,the chromogenic substance Ag Cit was immobilized on the carrier membrane to prepare visualized fast enzyme sheets for dimethoate.The constructed colorimetric sensor has excellent detection performance and good practicability in vegetable samples.The detection results of the developed rapid detection enzyme sheets can be recognized by the naked eye within 5minutes.（2）A visual rapid test strip for ethyl carbamate of liquor based on aptamer recognition was developed.The EC1-34 aptamer was used as a recognition molecule,which was coated with nano-gold（Au NPs）to prepare a recognition probe,and cationic polymer was selected as the efficient trapping agent for the recognition probe.The test strip has excellent detection performance for ethyl carbamate in liquor.The developed test strip has a short detection time,usually achieving a stable and visible color development effect within 10 minutes.The results are visible to the naked eye when the concentration of ethyl carbamate in the sample solution is higher than 20 mg×L^-1.Compared with the previously reported methods for the detection of dimethoate,the colorimetric sensor and rapid detection enzyme sheets constructed in this manuscript have the advantages of high detection sensitivity,strong specificity,good practicality,rapid detection speed,and visible detection results.Moreover,the test strip also has good specificity and practicality.Compared to traditional detection methods,the developed test strip has good specificity,stability,and portability,and does not rely on professional equipment,which can meet the needs of real-time on-site detection.Therefore,this study will provide new ideas and technical support for constructing real-time monitoring methods for other small molecule hazards.