A simple, inexpensive, reliable and environmentally friendly method based on ultrasound assisted extraction (UAE) combined with dispersive liquid-liquid microextraction with solidification of floating organic drop (DLLME-SFO) was developed for the simultaneous determination of four triazines in fruit and vegetable samples. Parameters affecting the extraction process were studied and optimized. Under the optimum conditions (sonication time: 15 min; extraction solvent: 30.0 µL 1-undecanol; disperser solvent: 1.0 mL acetonitrile; pH: 7; and extraction time: 0 min), extraction recoveries for different fruit and vegetables are in the range of 65-86%. The calibration graphs are linear in the range of 5-800 µg kg-1, with the correlation coefficient (r2) higher than 0.9985. The limits of detection (LODs) are in the range of 1-2 µg kg-1, which are lower than the maximum residue levels (MRLs) established by various official organizations. Repeatability (intra-day) and reproducibility (inter-day) of the method based on five replicate measurements of 100 µg kg-1 of herbicides were in the range of 3.6-5.4% and 4.5-6.3%, respectively.
Keywords:
ultrasound assisted extraction; dispersive liquid-liquid microextraction; triazine herbicides; fruit; vegetables
