Determination of Paraquat in Water, Rice, and Urine Samples by Resonance Light Scattering Technique with DNA

Abstract

In this paper, a rapid and accurate method was developed for the determination of paraquat by a resonance light scattering (RLS) quenching technique with a common spectrofluorometer. In the presence of paraquat, the intensity of resonance light scattering (I _RLS ) of DNA-HCL system was significantly quenched. A resonance light scattering peak at 308 nm was found. At this wavelength, the decrease in I _RLS was in proportion to the concentration of paraquat. The linear range of the calibration curve was approximately 0.05–1.0 μg mL⁻¹ and the detection limit (S/N = 3) was 0.036 μg mL⁻¹. The recovery rates of paraquat in river water, rice, and urine samples were determined with satisfactory results. The solid-phase extraction was used for the preparation of urine sample. The spectral characteristics of the ctDNA-paraquat-HCl system were also discussed.

Keywords:

• ctDNA
• Environmental sample
• Paraquat
• Quenching effect
• Resonance light scattering

Acknowledgments

This work was supported by the Natural Science Foundations of China (No. 20575005).

Notes

^a Conditions: ctDNA, l.0 mg L⁻¹; paraquat, l.0 mg L⁻¹; HC1, 0.005 mol L⁻¹.