The excessive use of pesticides is a serious health problem due to their toxicity and bioaccumulation through the food chain. Due to the complexity of foods, the analysis of pesticides is challenging often giving large matrix effects and co-extracted compounds. To overcome this problem, a selective and “green” supercritical fluid extraction method was developed, using neat carbon dioxide as a solvent at pressures of up to 800 bars. A Box–Behnken response surface experimental design was used, with the independent variables of density (0.70−1.0 g mL−1), temperature (40−70 °C), and volume (10−40 mL) of solvent, and the dependent variable of extracted amount of pesticides. The optimum extraction condition was found at the use of 29 mL of supercritical CO2 at 0.90 g mL−1 and 53 °C (corresponding to 372 bars of pressure). It was observed that increasing the density of CO2 significantly increased the extraction recovery of endrin and 2,4′-dichlorodiphenyldichloroethane. Matrix-matched calibration curves showed satisfactory linearity (R2 ≥ 0.994), and LODs ranged from 0.2 to 2.0 ng g−1. Precision was lower than 11% and recoveries between 80%–103%. Thus, the developed method could efficiently be used for trace analysis of pesticides in complex food matrices without the use of organic solvents.

The intensive application of pesticides to increase crop production has resulted in contamination of the agricultural products. Due to their occurrence at trace levels and the complexity of food samples, analysis of pesticide residues requires selective and efficient sample preparation methods. For this purpose, an extraction method based on supercritical carbon dioxide and acetonitrile as entrainer solvent was developed for trace analysis of atrazine, diazinon, chlorothalonil, and deltamethrin pesticides in honey samples. A Box-Behnken experimental design was applied to optimize extraction variables including static extraction time(5-15 min), pressure (200-700 bar), and temperature (45-70 • C). The optimum extraction conditions were found to be 11.5 min static extraction time, 252 bar, and 70 • C. The proposed analytical method showed a good linearity (≥0.998), low limit of detection (0.005-0.009 mg/kg), and good extraction recovery (74-111%). The precision study of the proposed method at two concentration levels of each pesticides, 0.25 and 1.0 mg/kg was found to be in the ranges of 2.3-4.21% for intraday (n = 3) and 3.93-8.02% for interday precisions (n = 3). The developed method is promising for use in trace analysis of pesticides in complex food samples including honey.

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