Preparation Of Fluorescent Probe Of Metal Milk Amino Acids And Its Application In Pesticide Detection

Fluorescence analysis,as a sensitive and reproducible detection method,has been widely used in medicine,chemistry,biology,botany and other fields.Most of the fluorescence substrates of traditional fluorescent probes are hydrophobic hydrocarbons with large π-conjugated system with high biotoxicity and carcinogenicity.In recent years,fluorescence detection technology has gradually developed towards the aspect of low toxicity and environmental protection.Amino acids,as a kind of easily modified natural green high fluorescence quantum system,are often used as fluorescence substrates for various types of detection.In this paper,milk amino acids are obtained by chemical treatment of skimmed milk,which are used as fluorescence substrate,and metal ions are used as quenching agent and recognition ions to detect oxime group and organophosphorus respectively.In the process of exploring the treatment method of milk,the experimental conditions are obtained to maximize the fluorescence quantum yield of milk amino acid system,that is,1.5mL milk is added with 150 μL NaOH solution(5 M),and then diluted to 20 mL with deionized water after stirring.The pH value of the solution is about 12.92.It is kept in a water bath at 50 ℃ for 24 h.The chemically treated milk amino acid fluorescence substrate not only the problems of protein salting out and denaturation are solved,but also the treated system has higher fluorescence quantum yield and dispersion compared with untreated milk.Then,through the quenching effect of metal ions on amino acids,the fluorescence of the obtained milk amino acid fluorescence substrate is reduced,and two kinds of fluorescence probes are prepared:Nickel Ion Milk Amino Acid Fluorescence Probe and Ferric Ion Milk Amino Acid Fluorescence Probe.The sensitivity of the system is the highest when the concentration of metal ions(nickel or ferrum)in the solution is 1mM.Then,the difference between the stability constant of milk amino acid and the material under test caused by metal ions is used to replace the metal ions in the structure of the metal ionmilk amino acid system,so that the fluorescence of the system could be recovered.The change of optical properties in the system is used to quantitatively detect the substance to be measured.The Nickel Ion Milk Amino Acid Fluorescence Probe showed outstanding performance in the detection of oxime-group substances with the detection limit as low as 6.5062 μM,and the Ferric Ion Milk Amino Acid Fluorescence Probe also showed excellent performance in the detection of organophosphorus substances with the detection limit up to 16.360μM.In this paper,common milk in daily life as a fluorescent substrate to make fluorescent probe.The probe has the advantages of simple synthesis process,high fluorescence quantum yield,green system,short reaction time,simple operation,low price and easy availability of raw materials,rapid response during detection,extremely high sensitivity and linear relationship between oxime group and organophosphorus,good reproducibility of experiment,and less sample consumption.The synthesis of two probes provide a new idea for the real-time monitoring and detection of oxime-based pesticides and organophosphorus insecticides besides enzyme inhibition and chromatography.