## 3 Results and Discussion
### Comparison of Interaction Parameters of PILs-Based Stationary Phases  
The six different columns prepared were studied using the [PERSON] model to determine their solvation parameters, and to obtain information on the specific interactions that can be provided [47; 48]. Although the resulting properties must be assigned to the two components of the composite, the fused silica, and the polymeric ionic liquid, changes in those properties must be ascribed to changes in the PIL and, more specifically, to the modification in the crosslinking degree, which represents the most relevant structural change. It must be noted that the stationary phase containing 60% of DVB (PIL60) could not be properly characterized, due to the lack of elution of most of the compounds at 60 \({}^{\circ}\)C and 90 \({}^{\circ}\)C and for the excessive asymmetry of the peaks observed, which generated large errors in the [PERSON]'s model. The values of all the solvation parameters calculated for the other stationary phases are shown in Table 3. As can be seen, a slight decrease in the system constants was observed when increasing the temperature for all stationary phases, as usually occurs in gas chromatography analysis [47; 48; 52; 54]. In all cases, the hydrogen bond basicity (a-term) and the dipole interactions (s-term) are the dominant system constants, followed by the hydrogen bond acidity (b-term) and the term involving dispersion forces (l). In imidazolium ILs, the structure of the cation and anion involved determines their acid/basic properties, as well as the values obtained for other parameters [54]. As the nature of both the cation and the anion in the PIL component remain constant for all the columns studied, the differences observed must be assigned to the crosslinking of the polymers, most likely associated with changes in the mobility and accessibility of the functional groups in the PIL coating, and to the possible generation, for the higher crosslinking degrees, of polymer domains with different polarities, which could also contribute to the low performance of PIL60. The hydrogen bond basicity (a-term) in imidazolium ILs has been shown to be essentially dependent on the nature of the anion. The value of this parameter for the five different columns is relatively similar as they share the NTf\({}_{2}\) anion for the imidazolium cation (ca. 1.77 \(\pm\) 0.13 at 60 \({}^{\circ}\)C) and is also similar to the value calculated for ILs containing this anion (i.e., 1.752 for BMIM-NTf\({}_{2}\) at 70 \({}^{\circ}\)C) [54]. A value of 1.377 has been reported for a commercial IL-based column (1,9-di(3-vinylimidazolium) nonane bis(trifluoromethyl sulfonyl)imide at 120 \({}^{\circ}\)C [23], a value close to that found in our case (1.23 \(\pm\) 0.22), The hydrogen bond acidity (b-term), on the other hand, is different from zero for all stationary phases studied. This is relevant in comparison to most commercial stationary phases (i.e., HP-5 and ZB-WAX), where the b-term is practically zero [47; 48; 55], and represents a clear competitive advantage of these columns containing composite materials based on polymeric ionic liquids from AAILs. The presence of acidic hydrogen atoms at positions 2, 4, and 5 of the imidazolium ring contributes to the acidity observed in this family of ILs. In the present case, however, the value observed is significantly higher (0.66-0.90 at 60 \({}^{\circ}\)C) than that reported for BMIM-NTf\({}_{2}\) (0.378 at 70 \({}^{\circ}\)C) [54]. The presence of AAIL 4 of an amide functionality providing an additional hydrogen bond donor group and preserved in all prepared PILs can explain this fact. A similar value for the b-term has been reported for an imidazolium bistriflamide salt displaying a hydroxyl group [55],