Simultaneous determination of different pesticites with switchable and binary dispersive liquid-liquid microextraction strategies with high accuracy and sensitivity

In recent years, the determination of pesticides which pose great risks to human health has gained importance in different environmental samples. The determination of pesticides at trace levels in wastewater systems is extremely important because it helps to develop effective treatment strategies for the removal of contaminants from wastewater systems. For this purpose, different microextraction strategies have been used in the literature and each strategy provides new contributions towards high accuracy and sensitivity. Within the scope of this thesis, two accurate and sensitive methods namely: switchable liquid-liquid microextraction and binary liquid-liquid microextraction were used to preconcentrate clorflurenol and procyimidone from wastewater matrices. All experimental parameters of the two analytical methods were optimized and the analytical performance of each system was determined under the optimum conditions obtained. After determination of the system's analytical performance, applicability of the developed methods was validated by recovery studies in wastewater matrices. The limits of detection determined for clorflurenol and procymidone using switchable liquid-liquid microextraction was 3.5 µg L-1 ve 0.44 µg L-1 for clorflurenol and procymidone, respectively. The enhancements in detection power recorded by this method for clorflurenol and procymidone were 17 and 59 folds, respectively. Similarly, the limits of detection determined using the binary dispersive liquid-liquid microextraction was 0.57 µg L-1 ve 0.30 µg L-1, respectively. The enhancements in detection power recorded over the conventional GC-MS were 105 and 233 folds for clorflurenol and procymidone, respectively. Spike studies were carried out to test the effectiveness of the analytical method in real wastewater samples by determining percent recoveries. Application of binary dispersive liquid-liquid microextraction to university wastewater, dam lake and Hospital wastewater samples spiked with the two analytes yielded percent recoveries in the range of 87.3-116.5%. Similarly, spiked recovery tests performed municipal wastewater, hospital wastewater and irrigation canal water using the switchable liquid-liquid microextraction method produced results in the range of 86.3-115.4%. The closeness of the results to 100 validates both methods as accurate and applicable to real samples.