This work aims to study the degradation of estrone, 17β-estradiol, 17α-ethinylestradiol, and estriol under direct solar radiation, with an average irradiance value of 5.2 kWh/m 2 . Degradation at different temperatures (4°C, 20°C, and 30°C) was also tested in darkness. Individual solutions of the four estrogens were prepared and subjected to the conditions referred to above. The degradation for each compound was followed, after 7, 14, 21, 28, 35, 63, 91, and 126 days measuring the absorbance at the wavelength of 281 nm. The degradation of the four mixed estrogens was determined using capillary electrophoresis (CE), with a diode array detector and cholic acid, sodium salt plus sodium borate as a background buffer. The results showed no significant degradation rates on samples subjected to different temperatures. However, the results from CE analysis showed that, under direct solar radiation, after 126 days, the degradation rate varied between 75% and 100%. Also, the UV-Vis showed significant changes in the shape of UV-Vis spectra under direct solar radiation.
Fluoxetine is the most prescribed drug for treatment of depression. Recently, its presence in aquatic environment has been receiving a growing interest as several studies assessed its effects on aquatic fauna. Therefore, it's important to have an analytical method capable of monitoring these compounds at low concentrations. In this study, a new method was developed based on dispersive liquid–liquid microextraction to preconcentrate fluoxetine in a small volume of water sample (6 mL) before chromatographic analysis using ultra high performance liquid chromatography with fluorescence detection. Effect of composition and volume of extracting mixture, sample pH, vortexing time and salt addition were evaluated. Optimization of extraction conditions lead to an enrichment factor of 61 ± 18. After extraction optimization, recovery percentages of fluoxetine spiked into different water matrices between 83–110% were obtained. For the optimized method, the calibration curve was obtained in the range of 160–2500 ng/L with a limit of detection of 98.9 ng/L and a limit of quantification of 329.8 ng/L.
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