## 1 Introduction  
Plastic and rubber materials or materials with a polymeric coating [1] are currently used in various applications, including laboratory or technological equipment. Except for disposable items (pipette tips, vials, containers, gloves, etc. ), many of these materials are designed for repeated use, such as instrument hoses. Tubing materials are desired to be durable, inert and resistant to mechanical and chemical irritation, especially in applications such as advanced oxidation processes (AOP), where specific oxidative and irritating conditions can occur [2; 3; 4]. In addition to chemical resistance, resistance to fluctuating and abrasive process conditions, thermal conductivity, fabrication capabilities and design play significant roles in the decision-making process. Nevertheless, when used in contact with hydrophobic compounds, their polymeric nature poses a risk of contamination. Unwanted sorption (adgortion/absorption) and desorption events of trace amounts of organic pollutants can cause severe discrepancies during sample handling and analyses [5; 6], especially when only trace and environmentally relevant quantities are present. Among factors that contribute to sorption may be the ability of a micropollutant to interact specifically with polymer functional groups, Gibbs free energy of the localized environment, and other factors. Moreover, the sorption could be enhanced by the surface roughness and microporosity of the polymer material. Due to the predominantly hydrophobic nature of many organic pollutants, polymeric materials are expected to interact with them through weak hydrophobic interactions, van der Waals forces or noncovalent interactions [5; 7; 8]. Between them, natural estrogenic hormones, such as estrone (E1), 17\(\beta\)-estradiol (E2), estriol (E3) and synthetic contraceptive 17\(\alpha\)-ethinylestradiol (EE2) are emerging micro-pollutants established in the Watch List of Substances for European Union-wide monitoring reported in the Decision 2015/495/EU of 20 March 2015 [9] and US EPA [10]. Due to their hydrophobicity values expressed as log K\({}_{\rm ow}\) (see Table S1) and the high-risk coefficients, estrogens represent relevant model compounds [11; 12]. They are released into the environment via wastewater-treated effluents as they are poorly removed with conventional wastewater treatment plant (WWTP) processes [13; 14; 15; 16]. Various studies have reported their occurrence in aqueous and solid environmental matrices and tap water [17; 18; 19; 20; 21]. Although their concentrations in the environment were found in the ng/L range, they show high estrogenic potency. The presence and persistence of estrogens in the environment raise concerns regarding the potential adverse effects on the sexual and reproductive systems of wild animals, fish and humans [22; 23; 24; 25; 26]. The ability of estrogens to sorb onto the surfaces of various materials is used for their removal from the environment [27; 28; 29; 30; 31]. On the other hand, the sorption and following desorption of such chemicals can be a source of problems. For example, due to organic carbon as a sorbent (e.g., humic acids), they can reach deeper layers of soil (possessing divergent conditions), where they can be desorbed and thus contaminate groundwater [26; 32]. Similarly, plastic waste [33], especially microplastics [34; 35] as an important part of current environmental pollution, can serve as a source and vector for various chemicals in aquatic and terrestrial environments. The sorption of estrogens can also be a source of inaccuracy in analysis, especially when their concentrations are very low, as is usually the case in environmental samples. If estrogens sorb to the sample handling material or materials used for sample filtration, the results may be significantly underestimated or false negative [5; 25]. In addition, if they sorb to coupling material in AOP units, better degradation efficiencies may be falsely attributed to sorption.