Shulou(Shulou.com)11/24 Report--

CTOnews.com, July 24, CTOnews.com learned from the official website of Hefei Institute of Scientific Materials of the Chinese Academy of Sciences that the team of Jiang Changlong researchers of the Institute made new progress in the analysis and detection of carbamate pesticides and organophosphorus pesticide residues. Two efficient ratio fluorescent nanoprobes were designed and prepared, and combined with the color recognizer of smart phones, visual quantitative detection of pesticides in food and environmental water was realized. The related research results were published in the Journal of Chemical Engineering and ACS Sustainable Development Chemistry and Engineering Research.

Figure 1. A schematic diagram of the mechanism of visual detection of aminomethyl ester pesticide residues by ratio fluorescence probe.

Figure 2. A schematic diagram of the mechanism of rapid visual quantitative detection of organophosphorus pesticide residues by ratio fluorescence probe. Carbamates are mainly used as insecticides, acaricides, herbicides and fungicides, and have become a major category of pesticides. Organophosphorus pesticides are mainly used to control plant diseases, insects and weeds. These two pesticides are widely used in agricultural production, and there will be varying degrees of residues in crops. However, they degrade slowly in nature, and after their residues enter the body with breathing, skin absorption or accidental ingestion, drug toxins will damage the function of human organs, and in severe cases, respiratory paralysis or even death will occur, endangering human health. At present, the main analytical methods for the detection of pesticide residues at home and abroad are still limited to enzyme inhibition and immunoassay, which usually have some problems, such as high cost, complex operation, time-consuming and so on. Therefore, it is of great significance to develop new methods for pesticide detection with high speed, low cost, high specificity and high sensitivity.

In view of this, based on the principle of Strecker-like reaction induced by 2,3-naphthalenedialdehyde (NDA) and sulfite, an enzyme-free ratio fluorescence probe was constructed, using CdTe quantum dots (CdTe QD) as background fluorescence for full-spectrum visual recognition of carbamate pesticides (CPs). After the addition of CPs, the green fluorescent isoindole was produced by nucleophilic condensation reaction. The fluorescent probe showed an obvious color change from red to green, and achieved a rapid visual response to carbamate. The detection limit (LOD) was as low as 18.6 nM, which was much lower than the national maximum residue standard.

In addition, a ratio fluorescence probe was constructed by integrating green carbon dots and CdTe quantum dots (CdTe QD) for highly selective quantitative detection of methyl parathion (MP). Under alkaline condition, MP can be hydrolyzed rapidly to p-nitrophenol (p-NP). The transient reaction of hydrogen bond enhancement leads to the internal filtration effect between carbon point and p-NP to quench the green fluorescence, which leads to the sensitive fluorescence chromaticity change from green to red. The detection limit is as low as 8.9 nM.

The above work is supported by the national key R & D program, the National Natural Science Foundation project and the key research and development plan of Anhui Province.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.