## 3 Results  
### Characterization of Copolymers  
Copolymeric poly(4 VP-_co_-14 DMB) and poly(4 VP-_co_-TRIM) microspheres were obtained via seed swelling polymerization. It is a suitable method for preparing polymeric beads with small diameters and narrow particle size distribution, which are important parameters determining the use of such microspheres as sorbents in chromatographic applications. As a functional monomer, 4 VP was used, whereas 1,4-dimethoxyyloyloxybenzene or trimethylolpropane trimethacrylate acted as a crosslinking agent. In Figure 1, the schematic chemical structures of the obtained copolymers are presented. The proposed composition of monomers enables the synthesis of the crosslinked copolymers with the presence of the following polar functional groups: the carbonyl one derived from 14 DMB or TRIM monomer and basic pyridine one from 4 VP monomer that makes the copolymers less hydrophobic than the traditional poly(St-_co_-DVB) sorbent. On the other hand, the aromatic rings which are able to create \(\pi\)-\(\pi\) interactions are still present in the copolymer's structure. The chemical structures of poly(4 VP-_co_-14 DMB) and poly(4 VP-_co_-TRIM) sorbents were evaluated by ATR-FTIR measurements. In Figure 2, the obtained spectra of the copolymers are shown. The absorption bands observed between 1599 cm\({}^{-1}\) and 1558 cm\({}^{-1}\) derive from C=C and C=N stretching vibrations of the pyridine ring and confirm that 4 VP units are present in the copolymer network. On the other hand, a significant absorption band at 1745 cm\({}^{-1}\) is attributed to the C=O stretching vibration from 14 DMB and TRIM units. The second characteristic bands derived from the used crosslinkers are those in the region of 1173-1101 cm\({}^{-1}\) (COC stretching vibration). Thus, it was confirmed that the functional 4 VP monomer and crosslinked 1,4 DMB or TRIM monomers took part in the polymerization reaction. The obtained poly(4 VP-_co_-14 DMB) is a brand-new material, so for its detailed chemical structure characterization, the \({}^{13}\)C CP/MAS NMR analysis was also performed. It  
Figure 2: ATR-FTIR spectra of obtained 4 VP copolymers. confirmed the proposed in Figure 1 structure of the synthesized adsorbent. Taking into account the spectrum given in Figure 3, the broad signals derived from the resonance of carbon atoms are as follows: \(\delta\) = 188 ppm (C=O), \(\delta\) = 163 ppm (Ar C\({}_{8,3,2}\)), \(\delta\) = 136 ppm (Ar C\({}_{9,1}\)), \(\delta\) = 59 ppm (-CH\({}_{2}\)-, -CH-), \(\delta\) = 52 ppm (quaternary C), and \(\delta\) = 32 ppm (-CH\({}_{3}\)). Additionally, to assess the amount of 4 VP monomer incorporated into copolymeric structures, elemental analysis was performed. As is seen in Table 1, the percent of nitrogen in the structure of poly(4 VP-_co_-14 DMB) and poly(4 VP-_co_-TRIM) is 5.56% and 4.32%, respectively. The used for polymerization, 4 VP:crosslinking agent-relative molar ratio was 2:1. The calculation based on the elemental analysis results shows that in the prepared microspheres, the 4 VP ratio to 14 DMB is 1.72:1, and the 4 VP ratio to TRIM is 1.5:1. Both these molar ratios are close to the assumed ones. It also confirms that the obtained copolymeric networks consist of units derived from 4 VP and crosslinkers. The morphology of poly(4 VP-_co_-14 DMB) and poly(4 VP-_co_-TRIM) microspheres was determined by SEM measurements. As is visible in Figure 4 presenting the SEM images of the synthesized copolymers, the particles possess an ideal spherical shape. Their number average diameter is 8.18 \(\upmu\)m with a CV of 4.22% for poly(4 VP-_co_-14 DMB) and 9.25 \(\upmu\)m with a CV of 9.83% for poly(4 VP-_co_-TRIM). A CV value lower than 10% indicates that the microspheres are nearly uniform in size. For TRIM crosslinked microspheres, the D\({}_{\text{n}}\) value is higher than for those synthesized with 14 DMB. The chemical structure of TRIM is more expanded than that of 14 DMB, and TRIM possesses three methacrylate groups that can react during polymerization with 4 VP.