Preconcentration of elements as hydrophobic complexes with low-polar adsorbents

Data on the adsorption preconcentration of elements as hydrophobic complexes on nonpolar and low-polar adsorbents are reviewed and systematized. It is shown that inorganic (most often octadecyl silica), organic polymer (polytetrafluoroethylene and its analogues, styrene–divinylbenzene copolymers, polyurethane, cellulose), and carbon matrices (activated carbon, expanded graphite, fullerenes) are used for the extraction of elements in such systems. The “flexibility” of such preconcentration systems is demonstrated: impregnated and adsorption-modified adsorbents can be obtained, elements can be extracted as pre-synthesized synthesized hydrophobic complexes, and the desorption of elements can be performed with the destruction of such complexes or without it. It is shown that the large number of similar preconcentration systems enable the creation of effective configurations of hybrid and combined systems for analyzing various samples.