DETERMINATION OF PARAQUAT IN WATER, RICE, AND URINE SAMPLES BY RESONANCE LIGHT SCATTERING TECHNIQUE WITH DNA

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 mu g mL(-1) and the detection limit (S/N = 3) was 0.036 mu g 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.