## 1 Introduction  
The highly cross-linked polymers have many useful features, such as their well-developed porous structure, high thermal resistance, and low ability to swelling. This makes them very useful materials as adsorbents for purification and separation techniques [1; 2; 3; 4; 5]. In order to make their porous structure more suitable to adsorb a specific group of compounds, methods like surface sensitization or imprinting are used [6]. Additionally, functionalization reactions can be carried out to modify the chemical nature of their surface [7; 8]. Other methods allow for the design of surface properties of the polymer (e.g., polarity, acidity) while already at the stage of synthesis [9; 10]. These methods rely on the usage of monomers with functional groups, which give the polymer a specific character and are able to interact with an analyte. Their presence also helps to improve the wettability of the polymer, which is advantageous when uptake is carried out from the aqueous solutions. The chemistry of polymeric sorbent is particularly important in the case of analysis of polar analytes like phenols or pharmaceuticals that exhibit biological activity. Although their concentration in natural waters or sewage is on a low level, they pose a serious threat to the environment. All living organisms are exposed to the harmful effects of these substances and products of their decomposition. A lot of such compounds are not biodegradable, and remain in the environment for a very long time. This type of pollution may lead to contamination of drinking water. For this reason, governments around the world introduced directives on maximum limit values for the most toxic compounds and the requirement for constant monitoring of their presence [11; 12; 13; 14]. Moreover, if pollutants are very diluted, it is an additional difficulty from an analytical point of view, as a stage of quantitative isolation and concentration should be included in the determination procedure [1; 15]. For many years analytical methods for extraction of phenolic compounds based on liquid-liquid extraction (LLE) and Soxhlet extraction, for liquid and solid samples, respectively [16]. These methods are expensive and time consuming therefore SPE (solid phase extraction) as more convenient, cheap, fast and environmentally friendly method was proposed [1]. Due to differentiated chemical character of pollutants there is no one universal adsorbent suitable \"for all purposes\". Depending on the properties and molecular size of an analyte, the right adsorbent should be selected. The most important features of the adsorbent are: Porosity, surface chemistry and stability, both chemical and thermal. Porosity affects sorption capacity. Chemical structure determines its usefulness for a particular type of analytes. Chemical and thermal stability influences the regime of working conditions, especially in the stage of recyclability. Many studies were performed to evaluate the usefulness of commercially available sorbents like Isolute ENV, PLRP-S, PGC, LiChrolut EN, Bond Elut Env, OASIS HLB [17; 18; 19] also newly prepared materials are examined [20; 21; 22; 23]. Researchers used stationary and dynamic methods, different experimental conditions and sample matrices. In addition, the way of presentation of the data is not unified. For this reason, it is difficult to compare results obtained by various groups. In order to model the sorption process usually one-component solutions are used, but from the practical applications point of view, studies performed for multicomponent mixtures are more useful. In this work we present the series of highly cross-linked porous polyvinylbenzenes (pDVB). The aim of our study was the evaluation if the addition of a potential adsorbate to pore forming agents in the stage of polymerization will have an influence on a porous structure and sorption properties of the synthesized polymer towards the added adsorbate.