title: A label-free silicon quantum dots-based photoluminescence sensor for ultrasensitive detection of pesticides.
abstract: Sensitive, rapid, and simple detection methods for the screening of extensively used organophosphorus pesticides and highly toxic nerve agents are in urgent demand. A novel label-free silicon quantum dots (SiQDs)-based sensor was designed for ultrasensitive detection of pesticides. This sensing strategy involves the reaction of acetylcholine chloride (ACh) with acetylcholinesterase (AChE) to form choline that is in turn catalytically oxidized by choline oxidase (ChOx) to produce betaine and H2O2 which can quench the photoluminescence (PL) of SiQDs. Upon the addition of pesticides, the activity of AChE is inhibited, leading to the decrease of the generated H2O2, and hence the PL of SiQDs increases. By measuring the increase in SiQDs PL, the inhibition efficiency of pesticide to AChE activity was evaluated. It was found that the inhibition efficiency was linearly dependent on the logarithm of the pesticides concentration. Consequently, pesticides, such as carbaryl, parathion, diazinon, and phorate, were determined with the SiQDs PL sensing method. The lowest detectable concentrations for carbaryl, parathion, diazinon, and phorate reached 7.25 × 10(-9), 3.25 × 10(-8), 6.76 × 10(-8), and 1.9 × 10(-7) g/L, respectively, which were much lower than those previously reported. The detecting results of pesticide residues in food samples via this method agree well with those from high-performance liquid chromatography. The simple strategy reported here should be suitable for on-site pesticides detection, especially in combination with other portable platforms.
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha 410081, P. R. China.
authors.forename: Yinhui
authors.initials: Y
authors.lastname: Yi
authors.forename: Gangbing
authors.initials: G
authors.lastname: Zhu
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Youyu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Haitao
authors.initials: H
authors.lastname: Li
authors.forename: Jiangna
authors.initials: J
authors.lastname: Zhao
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D008163:Luminescent Measurements / Q000379:methods*; D010575:Pesticides / Q000032:analysis*; D045663:Quantum Dots / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*
chemical_list: D010575:Pesticides; D012825:Silicon