Ultrasonic solvent extraction and nonaqueous CE for the determination of herbicide residues in potatoes.

In the present work we address the development of a simple and effective method for the determination of triazine herbicide residues in horticultural products by CE in nonaqueous media (NACE). Potato samples were selected as a representative matrix of such foods with a nonfatty content. Isolation of the analytes from the sample matrix was accomplished by extraction with organic solvents, assisted by ultrasound; a clean-up step of the organic extracts was carried out with SPE, using an Oasis MCX(R) sorbent to retain the analytes directly from the organic medium. The detection limits achieved in spiked potatoes (1.7-4.0 mug/kg) were lower than the default value of maximum residue level (MRL) established by current EU legislation for pesticide residues in foodstuffs. The results obtained were compared with HPLC in order to evaluate the performance of the NACE procedure.