Residue and dissipation kinetics of thiamethoxam in a vegetable-field ecosystem using QuEChERS methodology combined with HPLC–DAD

• Published in: Food chemistry 2014-09, Vol.159, p.1-4
• Main Author: Abd-Alrahman, Sherif H.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Chromatography, High Pressure Liquid - methods; Dissipation; Ecosystem; Food toxicology; HPLC; Kinetics; Medical sciences; Neonicotinoids; Nitro Compounds - analysis; Oxazines - analysis; Pesticide Residues - analysis; Pesticides, fertilizers and other agrochemicals toxicology; Potato; QuEChERS; Soil - chemistry; Soil Pollutants - analysis; Solanum tuberosum - chemistry; Thiamethoxam; Thiazoles - analysis; Toxicology
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2014.02.124

•This is the first study to investigate the dissipation kinetics of thiamethoxam in potato tubers and soil samples.•A rapid and sensitive method to determine thiamethoxam residues in vegetables were developed.•The dissipation kinetics of thiamethoxam was followed first-order rate kinetics at standard recommended dose application. The dissipation kinetics and residual levels of thiamethoxam in potato and soil under field ecosystem were determined using a QuEChERS method with HPLC–DAD. At fortification levels of 0.05, 0.1, 0.25, 0.5, 1.0 and 5.0mgkg−1, it was shown recovery was 99.4% (95.3–103.5%) for potato tubers, and 88.5% (86–91%) for soil with coefficient variation of the method (CV%) was less than 4% in potato tubers, and in soil less than 11%. For repeatability ranged from 1.27% to 4.77%. The LOD and LOQ were estimated to be 0.02 and 0.06mgkg−1, respectively. The half-lives were 2.92 and 1.4days, respectively. The terminal residues of thiamethoxam were below the maximum residue limit (MRL 0.2mgkg−1) after 6days, which considered to be safe for human beings. These results contribute to establishing the scientific basis of the dosage of thiamethoxam for use in vegetable-field ecosystems.