A QuEChERS method was developed for the analysis of diazinon, chlorfenapyr, and lufenuron in Napa cabbage. These pesticides represent three different chemical classes and are commonly used in cabbage production in Korea. The objective of the proposed method is a fast, inexpensive, and easy extraction of pesticides, followed by rapid analysis. The proposed method involves a microscale extraction using acetonitrile and dispersive solid phase extraction (SPE), allowing for time and materials savings. The pesticides were separated and quantified using reversed-phase HPLC-UV at 220 nm. The calibration curves showed good linearity (R2>0.97), and the limits of detection and quantification were ≤0.05 and 1 mg/kg, respectively. Intraday and interday recoveries were in the range 97-116% and 101-112% with RSD% ≤9% for concentrations between 0.5-5 mg/kg. Abnormal recoveries and a substantial matrix effect were initially observed for lufenuron, signaling that optimization of lufenuron recovery requires a slight modification of the method. The proposed method was tested on cabbage samples sold at local markets, which showed no detectable residues of the target pesticides. The proposed method could thus be used for monitoring these pesticides in cabbage and similar vegetables.

• Ahmed Gotah
• Coralia V. Garcia
• Sam-Pin Lee
• Key Whang Corresponding author