Combination of Ultrasound-Assisted Extraction and Ultrasound-Assisted Emulsification Microextraction for Separation and Enrichment of Permethrin and Deltamethrin Residues in Spinach Samples

A simple, inexpensive, reliable and environmentally friendly procedure based on ultrasound-assisted extraction combined with ultrasound-assisted emulsification microextraction based on applying low density organic solvent followed by gas chromatography-flame ionization detection has been developed for the simultaneous determination of permethrin and deltamethrin in spinach samples. Parameters affecting the extraction process have been optimized. Under the optimum conditions, the calibration plots were linear in the range of 0.01–20 mg/kg with the determination coefficient (r2) higher than 0.990. The limits of detection were 0.007 and 0.006 mg/kg for deltamethrin and permethrin, respectively, which are lower than the maximum residue levels established by various official organizations. The proposed procedure has high potential for the use as a sensitive method for the determination of deltamethrin and permethrin residues in spinach samples.