Salting-Out Assisted Liquid–Liquid Microextraction and Reverse-Phase Chromatographic Quantification of Two Neonicotinoid Insecticides from Fruits and Vegetables

Abstract

The present monograph describes the salting-out assisted liquid–liquid microextraction (SALLME) and reverse-phase high-performance liquid chromatography with diode array detector (RP-HPLC-DAD) based quantification of two frequently applied neonicotinoid insecticides, i.e., acetamiprid (ACE) and imidacloprid (IMD), from selected tropical fruits (citrus and guava) and vegetables (tomato, okra and cauliflower). The SALLME conditions like pH, liquid/solid ratio and salt ratio (NaCl/Na2SO4) were varied over a wide range of conditions for the enhanced recovery of IMD and ACE from spiked quality control (low, high and medium) of fruits and vegetables. Meanwhile, RP-HPLC-DAD quantification of IMD and ACE was found to be linear over 1–100 μg/L with the coefficient of determination (R2) value ≥0.997 and slope of the calibration curve (sensitivity) ≥2.3 × 104 peak area unit (μAu). The analysis of selected fruits and vegetables after 0 (1 h), 1, 3, 7, 10 and 14 days of foliar application revealed the presence of IMD and ACE residues in okra and guava higher than maximum residual limits set by the Codex Alimentarius Commission until the third day of spray. Overall, the SALLME-RP-HPLC-DAD was found to be a rapid, selective and expedient choice for the routine analysis of neonicotinoids in environmental and food commodities.