A new and efficient analytic methodology based on cloud point extraction (CPE) was developed for determination of pesticide residues of metsulfuron-methyl (MSM), chlorsulfuron (CS), and bensulfuron-methyl (BSM) in water, soil, and rice grain by high-performance liquid chromatography (HPLC). Multiple experimental conditions that affected CPE efficiency-including surfactant type and concentration, equilibration temperature and duration, ionic strength, and solution pH were identified. CPE conditions were optimized as follows: 1.5% Triton X-114 (w/v), 12% Na(2)SO(4) (w/v) solution (pH 2.0), and heat-assisted at 50 °C for 15 min. The calibration curves for all analytes were linear, ranging from 0.05 to 4.0 mg L(-1), with the correlation coefficients >0.9995 by HPLC-ultraviolet detector and were linear, ranging from 0.004 to 2.0 mg L(-1), with correlation coefficients >0.9983 by CPE-HPLC. The average recoveries at the three spiked levels using CPE ranged from 86.0% to 94.5% for water samples with relative SDs (RSDs) of 0.4% to approximately 7.8%; from 85.6% to 94.8% for soil samples with RSDs of 1.2% to approximately 9.5%; and from 81.9% to 91.3% for rice samples with RSDs of 1.7% to approximately 5.8%. The proposed CPE-HPLC method can be successfully used to analyze MSM, CS, and BSM residues from contaminated water, soil, and rice grain samples.

A molecularly imprinted polymer (MIP) was prepared using chlorsulfuron (CS), a herbicide as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a cross-linker, methanol and toluene as a porogen, and 2,2-azobisisobutyronitrile as an initiator. The binding behaviors of the template chlorsulfuron and its analog on MIP were evaluated by equilibrium adsorption experiments, which showed that the MIP particles had specific affinity for the template CS. Solid-phase extraction (SPE) with the chlorsulfuron molecularly imprinted polymer as an adsorbent was investigated. The optimum loading, washing, and eluting conditions for chlorsulfuron molecularly imprinted polymer solid-phase extraction (CS-MISPE) were established. The optimized CS-MISPE procedure was developed to enrich and clean up the chlorsulfuron residue in water, soils, and wheat plants. Concentrations of chlorsulfuron in the samples were analyzed by HPLC-UVD. The average recoveries of CS spiked standard at 0.05~0.2 mg L(-1) in water were 90.2~93.3%, with the relative standard deviation (RSD) being 2.0~3.9% (n=3). The average recoveries of 1.0 mL CS spiked standard at 0.1~0.5 mg L(-1) in 10 g soil were 91.1~94.7%, with the RSD being 3.1~5.6% (n=3). The average recoveries of 1.0 mL CS spiked standard at 0.1~0.5 mg L(-1) in 5 g wheat plant were 82.3~94.3%, with the RSD being 2.9~6.8% (n=3). Overall, our study provides a sensitive and cost-effective method for accurate determination of CS residues in water, soils, and plants.