Determination of Paraquat by Cucurbit[7]uril Sensitized Fluorescence Quenching Method

Abstract

A method for the determination of paraquat by cucurbit[7]uril (CB[7]) fluorescence quenching was developed. The assay was based on the reaction of the CB[7] with acridine orange. The fluorescence intensity of acridine orange regularly increased with the addition of CB[7]. However, while an appropriate amount of paraquat was added to the CB[7]- acridine orange system, the fluorescence intensity of the system was quenched which was employed to determine paraquat. Under the optimum conditions, a linear range of 3.0–800 nmol L⁻¹ and a detection limit of 1.61 nmol L⁻¹ for paraquat were obtained. The simple strategy reported here offers great practical potential for the determination of pesticide residues in agricultural products.

Keywords:

• Competitive inclusion
• Cucurbit[7]uril
• Fluorescence spectroscopy
• Paraquat

Acknowledgments

This work was supported by Natural Science Foundation of China. (20875002).