Microextração líquido-líquido dispersiva assistida por vortex e ultrassom aplicada à determinação de diferentes classes de pesticidas em água

Abstract

This study comprised the development and validation of a method of liquid-liquid microextraction dispersive with emulsification assisted by vortex and ultrasound (USVADLLME) for the simultaneous determination of four triazines (ametrina, atrazine, prometryne and terbuthylazine), two triazinones (metribuzin and hexazinone) and one triazole (flutriafol) in water. The analytes quantitation was performed by gas chromatography with mass detection (GC-MS). The experimental condition that provided the best results were: 5.00 mL of sample, 100 µL extractor solvent toluene and 1 minute of sonication at 40º C. At this conditions, the method detection limit (MDL) ranged from 0.10 to 2.71 μg L-1 for flutriafol to terbuthylazine, respectively. The linear working range was 1.00 to 150 μg L-1 . The accuracy, measured in terms of percentage recovery was greater than 77.2% to all evaluated analytes. The repeatability and intermediate precision ranged from 1.4 to 9.0% and from 2.9 to 15%, respectively. The USVADLLME method was also applied to river water and stream water samples, with different physic chemical properties, and no matrix effects on the accuracy and precision of the method were not observed. These results suggest that USVADLLME -GC/MS may be used for the determination of these analytes in water, with the advantage of using small amounts of solvents, easy operation and low cost.