Ultrasound-assisted Extraction Methods for the Determination of Organic Contaminants in Solid and Liquid Samples

Ultrasound-assisted extraction is a common technique for the extraction of organic contaminants from solid samples due to its ease of application to a variety of matrices and the wide range of solvents that can be used. In recent years, many methods have combined sonication with microextraction techniques for liquid samples. Among the improvements in extraction techniques, there is an increasing interest in reducing the use of traditional organic solvents or replacing them with other less toxic solvents, such as ionic liquids due to the negligible vapour pressure of these solvents. However, these solvents are not fully green due to poor biodegradability and some toxicity to aquatic life. As a result of the growing interest in the so-called “Green Chemistry”, the use of more environmentally friendly solvents, such as deep eutectic solvents, or novel sorbents, such as magnetic nanoparticles, has been observed for the extraction of organic contaminants. This review provides an overview of the new applications of ultrasound-assisted extraction for the determination of organic contaminants, with special emphasis on the methods that implement the principles of Green Analytical Chemistry to reduce the environmental impact. In this article, the ultrasound-assisted extraction methods proposed in the last five years (2018–2022) are reviewed to update our previous review.