## 2 Materials and Methods
### _Plusico-Chemical Analysis_  
_Freeze drying method_ was used to dry the MIPs from water and obtain a powdered product using a Laboconc 7934030 freeze dryer (Laboconco Corporation, Kansas City, MO, USA). MIPs were first frozen at approximately \(-20\)\({}^{\circ}\)C and then freeze-dried.  
_The yield of the reaction product_ is the ratio of the mass of the resulting product to the mass that should theoretically be obtained. The theoretical mass of the substances was taken as the total mass of the monomers used. The yield of products was calculated using the following formula:  
\[\omega=\frac{m_{pract.}}{m_{theoret.}}*100\% \tag{1}\]  
_Fourier Transform Infrared (FTIR) Analysis_ was conducted using an FTIR Spectrometer, Nicolet iS10 FT-IR Spectrometer (Thermo Electron Corporation, Waltham, MA, USA), for the determination of the MIP structure. Samples for analysis were prepared using the ATR technique.  
_Scanning Electron Microscopy (SEM)_ was conducted using a ZEISS Crossbeam 540 SEM (Carl Zeiss Microscopy GmbH, Jena, Germany) to identify the product's surface morphology.  
_Adsorption method_ was used to study the sorption parameters (sorption degree, sorption capacity) of the imprinted structures. The optimal wavelength for a silver solution with a concentration of 0.5 g/100 mL vs. distilled water was obtained using a \"Shimadzu  
Figure 1: Synthesis of the MIPs.  
UV-1900\" UV-VIS Spectrophotometer (Shimadzu, Kyoto, Japan). Then, 5 different concentrations of solutions (0.3125, 0.625, 1.25, 2.5, 5 g/L) were made, and a calibration curve for silver nitrate with a wavelength of 425 nm was constructed as shown in Figure 2. The sorption experiment was carried out as follows: each MIP (0.2 g) was placed in a solution of silver nitrate with a concentration of 0.1 g/mL. During sorption, the absorbance was measured on the spectrophotometer every 15 min for 3 h for further concentration calculations (using a calibration curve). After 24 h, control measurements were made. Based on the obtained results, the sorption degree and sorption capacity were calculated.  
Sorption degree:  
\[\eta=\frac{C_{0}-C_{c}}{C_{0}}*100\% \tag{2}\]  
where \(C_{0}\) is an initial concentration of silver nitrate in a solution, in g/mL, and \(C_{c}\) is a concentration of silver nitrate in a solution at a certain time interval, in g/mL.  
Sorption capacity:  
\[Q=\frac{(C_{0}-C_{c})*V_{solution}}{m_{sorbent}} \tag{3}\]  
where \(C_{0}\) is an initial concentration of silver nitrate in a solution, in g/mL; \(C_{c}\) is a concentration of silver nitrate in a solution at a certain time interval, in g/mL; \(V_{solution}\) is a volume of solution of terbium nitrate taken for sorption experiments, in mL; \(m_{sorbent}\) is the mass of the MIPs taken for sorption experiments, in g.  
_Desorption experiments_ were conducted to study the polymer's surface release properties. The samples of the imprinted structures after sorption were placed into beakers containing a weak solution of nitric acid at a concentration of 0.05 M for this purpose. Similar to the adsorption analysis, the absorbance was determined using a \"Shimadzu UV-1900\" UV-VIS Spectrophotometer every 15 min for 3 h. A control absorbance measurement during desorption was performed at 24 h.