Benzotriazoles (BZ) are heterocycles, that can be found in households and industry as corrosion inhibitors and UV stabilizers. As a consequence of ever-growing anthropogenic activities, they have become globally present pollutants. Not only are BZ toxic for plants and aquatic organisms, but they are also endocrine disrupting chemicals and potential carcinogens. Even furthermore – some of BZ can bioaccumulate.
With increasing pollution, we seek newer and even greener methods for laboratory work. One of the most environmentally friendly solvents is of course water, which shows altered properties at elevated temperatures. From a polar solvent, it can become nonpolar under extreme conditions, and that is already used in environmental science.
In this work, I tested hot water extraction (HWE), whereby my goal was to determine the simplest benzotriazole (BTZ) in soil. According to available literature, mentioned method hasn’t been applied to this pollutant yet, so I sought the optimal extraction parameters. I varied the soil mass, time of cooking, amount of extraction solvent and its pH, however, none of the variations significantly changed the efficiency. So, on the basis of its anticorrosive function, I concluded that BTZ forms chelates with metal ions in soil and that this is the reason for my poorer results. Therefore, I added good chelating agent – EDTA, in my final experiment. It displaced the analyte, which then became free and available for extraction.
Because a simple variation of HWE was used – cooking in hot water in a beaker covered with a watch glass, I added an additional purification step with an already optimized solid-phase extraction (SPE). All samples were then analyzed with high-performance liquid chromatography with a diode-array detector (HPLC-DAD) by a previously developed method.
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