Study of the feasibility of focused microwave-assisted Soxhlet extraction of N-methylcarbamates from soil

A study of the feasibility of a focused microwave-assisted Soxhlet device for the extraction of N-methylcarbamates from soil has been performed. The main factors contributing to the extraction efficiency—namely microwave power, irradiation time and number of cycles—were optimized by means of a two-level full factorial design. The extracts were analysed by HPLC–post-column fluorescence derivatization–detection at excitation wavelength 340 nm and emission wavelength 445 nm. The method has allowed the extraction of carbamate pesticides from contaminated soil with quantitative recoveries, similar to those provided by the US Environmental Protection Agency method 8318, without degradation of the target compounds during the extraction and using less organic solvent, as 75–80% of the extractant was recycled.