Nonpolar benzotriazoles are benzotrizole derivatives, usually hydroxyphenyl derivatives. Because they absorb the entire tropospheric spectrum of UV light, they are commonly used as UV stabilizers. As hydrophobic molecules they don't dissolve in water but accumulate in soil, sea or river sediment, or due to their lipophilic nature they bioaccumulate. Nonpolar benzotriazoles have become regarded as pollutants due to the potential negative impact on living organisms and the increasing release into enviroment. The problem with determination of nonpolar benzotriazoles in environmental samples is that they are found in low concentrations and sample pretreatment is crucial.
In my work, I have described the extraction methods used to extract nonpolar benzotriazoles from solid environmental samples. Soxhlet extraction is a simple technique but takes more time to extract. Other techniques used for extraction, such as ultrasonic-assisted extraction, microwave-assisted extraction, supercritical fluid extraction or pressurized liquid extraction are much faster techniques but all require additional, more expensive equipment. The aim of improving each of these techniques is to carry out the extraction with the best possible efficiency in the shortest possible time, using as few organic solvents as possible, which are also pollutants. After extraction, the extract needs to be purified and solid-phase extraction or gel-permeation chromatography are most commonly used for this.
Gas chromatography (GC) with various detectors, sometimes in combination with MS detector, is commonly used to determine concentrations of nonpolar benzotriazoles. Liquid chromatography (HPLC) can also be used in combination with MS detector.
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