Dissipation of Diethyl Aminoethyl Hexanoate (DA-6) Residues in Pakchoi, Cotton Crops and Soil

Abstract

QuEChERS procedure and acetonitrile extraction, oscillation and ultrasonic procedure followed by GC–MS and LC–MS/MS (QqQ) detections were established for determination of diethyl aminoethyl hexanoate (DA-6) residues in pakchoi, cotton leaf, cotton seed and soil. At concentration levels of 0.005–1 mg kg⁻¹, recoveries were in the range of 80.5%–103.3%, with a RSD less than 14.2%. The LOQs of methods were 0.005, 0.003, 0.005 and 0.001 mg kg⁻¹ for the pakchoi, cotton leaf, soil and cotton seed samples, respectively. DA-6 was applied in supervised field trials at GAP conditions to pakchoi and cotton. It was found that the dissipation half-lives of DA-6 were 5.4–8.2 days and 1.1–2.2 days and 1.5–1.9 days in cotton crop, pakchoi and soil respectively. At harvest, no detectable residues (<LOD) were found in cotton samples. However, residues was detected in pakchoi (0.007–0.013 mg/kg) in Beijing and soil (0.008–0.014 mg/kg) in Changsha in 2008.