Determination of Chlorpyrifos and Thiamethoxam in Potato Tuber (Solanum tuberosum L.) and Soil of Brazil Using Solid-Liquid Extraction with Low Temperature Partitioning (SLE/LTP)

The main objective of this work was to evaluate the presence of residues of chlorpyrifos and thiamethoxam in potato and soil samples under different circumstances after optimization and validation of solid-liquid extraction and partitioning at low temperature technique. Recovery percentages between 93% and 105% were obtained for pesticides in the samples. The optimized and validated method was applied to potatoes from supermarkets and it was obtained chlorpyrifos residue at concentrations of 0.67 mg kg(-1). Potatoes grown in the field were treated with pesticide on different days and chlorpyrifos was the only residue detected. The potatoes grown in pots were treated with chlorpyrifos and thiamethoxam only at planting. After 91 days, it was observed the concentration of thiamethoxam in the potatoes higher than the tolerable MRL. The proposed method was efficient in the determination of chlorpyrifos and thiamethoxam and it was concluded that the monitoring of pesticides in food must be performed periodically to ensure the product quality and the safety of consumer's health.