tailieunhanh - Mechanism to detect pesticide residues in tealeaves based on CdZnSe/ZnS ternary alloy quantum dots

In this report, we present the optical properties of the biosensors fabricated from CdZnSe/ZnS quantum dots. The optical properties such as absorption and emission of the ternary quantum dots before and after coupling with the protein molecules like streptavidine (SA) and acetylcholinesterase enzymes (AChE), forming a biosensor structure, will be presented. | Communications in Physics, Vol. 25, No. 1 (2015), pp. 67-74 DOI: MECHANISM TO DETECT PESTICIDE RESIDUES IN TEALEAVES BASED ON CdZnSe/ZnS TERNARY ALLOY QUANTUM DOTS NGUYEN NGOC HAI, NGUYEN HAI YEN, DUONG THI GIANG, DINH HUNG CUONG, NGUYEN DUC NHAT, PHAM THU NGA, AND DAO TRAN CAO Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay, Hanoi, Vietnam E-mail: haidhsphn@ Received 01 December 2014 Accepted for publication 26 March 2015 Abstract. In this report, we present the optical properties of the biosensors fabricated from CdZnSe/ZnS quantum dots. The optical properties such as absorption and emission of the ternary quantum dots before and after coupling with the protein molecules like streptavidine (SA) and acetylcholinesterase enzymes (AChE), forming a biosensor structure, will be presented. In particular, the changes in luminescence intensity according to the pH value of the solution environment containing biosensor have been considered, before and after the presence of pesticides. The changes in luminescence intensity of the biosensor after the presence of pesticide over time from 2 seconds to 26 minutes were also surveyed. We have carried out the tests to determine the trace amounts of commercial pesticides like Motox 5EC, containing 5% cypermethrin and Tungatin 10 EC, containing 10% abamectin, on the real samples of tealeaves. Some characteristics of the relationship between composition, structure, and special optical properties of ternary alloy quantum dots will also be presented. These studies open up the potential applications of ternary quantum dots for agricultural production. Keywords: Pesticide, biosensors, ternary alloy quantum dots, photoluminescence. I. INTRODUCTION Tea is the most popular beverage throughout the world. Among the factors limiting the quality and quantity of tea production, the role of insect pests is important. Management of pests in tea .