Extraction method for determining dinotefuran insecticide in water samples

Dinotefuran is a compound belonging to the third generation of nicotinoid insecticides, and has been effective in combating pests that are resistant to conventional insecticides, such as organophosphates, carbamates, and pyrethroids. This molecule presents high-water solubility (39,830 mg L-1 at 25 °C) compared to other pesticides, which facilitates its drag and leaching to lower soil layers. Therefore, the present study aimed to optimize and validate liquid-liquid extraction with low temperature purification (LLE-LTP) to determine dinotefuran residues in water by high performance liquid chromatography with diode array detection (HPLC-DAD). The results revealed that the analyte recovery ranged from 85.44 to 89.72% with a relative standard deviation <5.8. LLE-LTP was selective, precise, accurate, and linear in the range from 10.0 to 210 µg L-1, and presented limits of detection and quantification of 5.00 and 10.00 µg L-1, respectively. The matrix effect was <14%. The stability study of dinotefuran in water revealed significant stability of this molecule in water in the absence of light (>130 days), and a half-life of 7 days in water with sunlight. LLE-LTP coupled to HPLC-DAD was a simple, easy, and efficient method for extracting and analyzing dinotefuran in water samples.