## 2 Metal-Organic Frameworks
The use of the same SBU and similar organic ligands, e.g., terephthalatic acid, which may contain different substituents, e.g. (-Br, -NH\({}_{2}\), -COOH), but differing in length, leads to the formation of MOF families with the same lattice geometry but with different pore sizes. An example of such materials is isoreticular metal-organic frameworks (IRMOF) [7; 20]. Despite the existence of potentially millions of different combinations of metallic nodes and organic linkers, due to their impermanence or difficulty in synthesis, only a small part of them has gained popularity and is available on the commercial market. One of the advantages of MOFs is the possibility of modifying their structure in a wide range, which leads to a change in their properties and potential applications. In the case of using MOFs as sorbents in the process of preparing liquid samples for analysis, changes in the sorption selectivity of selected analytes are obtained. Modifying the MOF structure to change network properties can be done in several ways. The simplest method of modifying the resulting crystal structures is the appropriate selection of substrates for their production, but an MOF can also be modified after the synthesis is completed, that is, through post-synthetic modification (PSM) [9]. Due to the rapid development of this group of compounds and the relatively short history of their existence, the problem remains with the naming and affiliation of MOFs compared to other porous materials. We are also dealing here with a situation in which the rapidly growing amount of research on MOFs has exceeded the number of attempts to systematize and classify their nomenclature. The situation probably needs to be simplified by the unusual structure of the compounds in question. While exploring this topic, there have been several attempts to link MOFs with other materials and to give them appropriate names, although these are still only guidelines. To date, there are no strict rules governing how an MOF is named. One can encounter a situation where one structure can be correctly described with several names [16; 20; 21; 22]. The problem also concerned how to write the name of this group of compounds. Is the correct form a \"Metal-Organic Framework\", a \"Metal Organic Framework\", or an \"Organometallic Framework? Eventually, it was determined that the correct form contained a hyphen in the middle: \"Metal-Organic Framework\". The \"Organometal\" form has been reserved for complex compounds in which there is a direct M-C (metal-carbon) bond [16]. However, to this day, in some sources, both concepts are erroneously used interchangeably. The problem with the terminology of MOF also arose during the creation by individual universities and research institutions of common names and acronyms of materials developed by them, most often derived from the names of individual institutions, but not only. However, due to the high complexity of the structures of MOFs, acronyms formed from the names of individual universities and institutes have become an acceptable and popular way of naming this group of compounds [23]. The extraordinary properties of MOFs also translate into several practical applications. MOFs have found their applications mainly in gas storage (CO\({}_{2}\), H\({}_{2}\), CH\({}_{4}\), and others), in gas separation and purification processes, as catalysts in organic reactions, as drug carriers, as sensors (luminescent properties) [12; 24; 25], and recently as sorption materials in chemical analysis [20; 23]. In broadly understood chemical analysis, MOFs have proven themselves as sorbents during environmental contamination studies, food analysis, and in the chromatographic separation process. MOFs have also been used to remove environmental pollutants, in the process of wastewater treatment, the adsorption of hazardous materials from water and organic matrices, the removal of toxic and radioactive metal ions, aromatic compounds, air pollutants, and others [26].