title: Fluorescence Determination of Omethoate Based on a Dual Strategy for Improving Sensitivity.
abstract: Omethoate is a frequently used organophosphorus pesticide, and the establishment of a sensitive, selective, and simple method to determine omethoate is very important for food safety. In this paper, a dual strategy was applied to improve the detection sensitivity of omethoate. In the first strategy, graphene quantum dots (GQDs) were doped with nitrogen to increase the fluorescence quantum yield to 30%. By coupling N-GQDs with omethoate aptamer, an N-GQDs-aptamer probe was synthesized. The fluorescence of the N-GQDs-aptamer probe was turned off by graphene oxide (GO), but recovered by omethoate. Based on this principle, the fluorescence method for detecting omethoate was established with a detection limit of 0.041 nM. To further improve the detection sensitivity, the fluorescence polarization analysis method was applied as another strategy based on the polarization signal of GQDs. The detection limit was decreased to 0.029 pM by using the fluorescence polarization method. The detection limits in this paper were lower than those in other reports. The imaging of omethoate on plant leaves showed that the probe could be used for visual semiquantitative determination of omethoate.
authors.affiliation: School of Chemistry and Environment, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, South China Normal University , Guangzhou 510006, P. R. China.
authors.forename: Cuiping
authors.initials: C
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Environment, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, South China Normal University , Guangzhou 510006, P. R. China.
authors.forename: Bixia
authors.initials: B
authors.lastname: Lin
authors.affiliation: School of Chemistry and Environment, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, South China Normal University , Guangzhou 510006, P. R. China.
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Cao
authors.affiliation: School of Chemistry and Environment, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, South China Normal University , Guangzhou 510006, P. R. China.
authors.forename: Manli
authors.initials: M
authors.lastname: Guo
authors.affiliation: School of Chemistry and Environment, Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, South China Normal University , Guangzhou 510006, P. R. China.
authors.forename: Ying
authors.identifier: http://orcid.org/0000-0002-0369-2394
authors.initials: Y
authors.lastname: Yu
keywords: dual strategy; fluorescence method; fluorescence polarization; nitrogen-doped graphene quantum dots; omethoate