Recent advances in gels application for green analytical sample preparation

The ongoing quest for more environmentally sustainable analytical methodologies has led to the development of gels as highly versatile and promising materials for sample preparation. Their high surface area, adjustable porosity, mechanical stability, and the capacity to accommodate a diverse array of functional chemical groups, render them remarkably well-suited for the selective capture, retention, and regulated release of a broad spectrum of analytes. Recent studies have demonstrated significant advancements in the field of gel research and innovation, including hydrogels, ionogels, eutectogels, xerogels, aerogels, and cryogels. It has been demonstrated that the properties of gels can be modulated for a variety of sample preparation techniques, including solid-phase extraction, dispersive SPE, magnetic SPE, solid-phase microextraction, and matrix solid-phase dispersion. The synergy between gels and nanostructured materials, such as metal–organic frameworks, carbon nanotubes, graphene oxide, and magnetic nanoparticles, and many others, leads to a pronounced increase in extraction capacity and selectivity. Thus, gel-based materials are gaining attention over a wide range of analytical purposes, including environmental monitoring, food safety testing, and biological analysis.