Determination of tefluthrin insecticide in environmental water samples by magnetic solid-phase extraction and high-performance liquid chromatography

In today's world, the risks of pesticides have reached serious levels and the pollution caused by them has become an extremely important issue in terms of both human and environmental health. For this reason, the accuracy of the determination of pesticides at trace levels in water and wastewater systems and the applicability of the methods used are of great importance. Within the scope of this thesis, an analytical method was developed by enriching the Tefluthrin insecticide found in environmental water samples (tap water, surface water and wastewater) by magnetic solid-phase extraction (MKFE) method. Chromatographic analysis of Tefluthrin was carried out after optimizing the system parameters with HPLC-UV device. Fe3O4 nanoparticles were functionalized by coating with di-(2-ethylhexyl)phosphoric acid (DEHPA). After the characterization processes, DEHPA/Fe3O4 magnetic nanoparticles were used as adsorbent in magnetic solid-phase extraction. In the study, the optimization of experimental parameters such as adsorbent amount, type and volume of desorption solvent, adsorption time, desorption time, ion strength and pH, which affect the extraction efficiency, were made. As a result of the optimizations, the average extraction yield for tefluthrin was calculated as 76% under the most suitable extraction conditions. The detection and detection limit and relative standard deviation of the applied method for Tefluthrin were found to be 0.7 µg/L, 2.3 µg/L, 4.1% and 6.7%, respectively. In order to determine the applicability of the developed method in environmental water samples, recovery studies were carried out and the recovery values were determined in the range of 93-99% in tap water, 91% in surface water and 90-92% in wastewater from the Zonguldak region.