Residues of chlorantraniliprole in rice field ecosystem

Abstract

The fate of chlorantraniliprole was studied in rice field ecosystem, and a simple and reliable analytical method was developed for determination of chlorantraniliprole in soil, rice straw, paddy water and brown rice. Chlorantraniliprole residues were extracted from samples with acetonitrile. The extract was cleaned up with QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, and determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS). The average recoveries were 76.9–82.4% from soil, 83.6–89.3% from rice straw, 95.2–103.1% from paddy water and 84.9–87.7% from brown rice. The relative standard deviation was less than 15%. The limits of detection (LODs) of chlorantraniliprole calculated as a sample concentration (S/N ratio of 3) were 0.012μgL−1 for paddy water, 0.15μgkg−1 for soil, brown rice and rice straw. The results of the kinetics study of chlorantraniliprole residue showed that chlorantraniliprole degradation in soil, water and rice straw coincided with C=0.01939e−0.0434t, C=0.01425e−0.8111t, and C=1.171e−0.198t, respectively; the half-lives were about 16.0 d, 0.85 d and 3.50d, respectively. The degradation rate of chlorantraniliprole in water was the fastest, followed by rice straw. The final residues of chlorantraniliprole on brown rice were lower than maximum residue limit (MRL) of 0.02mgkg−1 after 14d Pre-Harvest Interval (PHI). Therefore, a dosage of 150mL a.i.hm−2 was recommended, which could be considered as safe to human beings and animals.