Adil Alshoaibi

In this work, a simple sensitive validated liquid chromatography mass spectroscopy (LC-MS/MS) analytical method was developed for the determination of Spirodiclofen residues in different aquatic toxic media. The toxic media were those that provide nutrients and help with the growth of different aquatic organisms for their survival and multiplication. The different media were the M4 medium for Daphnia magna and The Organization for Economic Cooperation and Development (OECD TG 201) medium for alga. Fe2O3-Ag2O/TiO2 nanocomposites were prepared by using a precipitation method, which was used as a photo-catalyst for the removal of Spirodiclofen pesticide from aquatic media. The experiment was performed under direct sunlight at a single fortification level (1.0 µg/mL) in M4 and OECD TG 201 media. The optimum catalyst concentration for the complete degradation was found to be 10 mg/L under sunlight. Spirodiclofen residues in water were determined by LC-MS/MS, and the rate constant DT50 (half-life) values were calculated from the obtained data. The results showed that with Fe2O3-Ag2O/TiO2 nanocatalyst, the DT50 (half-life) value was found to be approximately 8 h. These results revealed that iron-oxide- and silver-oxide-incorporated TiO2 nanocomposites were excellent photocatalysts when compared with TiO2, Fe2O3-TiO2, and Ag2O-TiO2 for the decontamination of pesticide residues in aquatic media samples.