## 4 Conclusions  
In this paper, a novel carbon paste electrode modified with core-shell structure Fe\({}_{3}\)O\({}_{4}\)@SiO\({}_{2}\) ion imprinted membrane was constructed for the determination of trace uranyl ions in the heterogeneous environment. Prior to the preparation of imprinted polymers, density functional theory (DFT) was utilized to investigate the complex matrix interaction between templates and binding ligands so as to screen out the best functional binding ligands, which can also lay the theoretical basis for the rationally designing MIIP/Fe\({}_{3}\)O\({}_{4}\)@SiO\({}_{2}\)/MCPE. The simulation design not only simplifies the experimental process, saves cost and time, improves the modification efficiency, but also generates a stable structure and better performance of the synthesized polymers. The synergistic effect of Fe\({}_{3}\)O\({}_{4}\)@SiO\({}_{2}\) modified IIP membranes on the modification of carbon paste electrode resulting in a larger specific surface area and excellent electron transfer capability on the electrode surface. Additionally, the magnetic core-shell imprinted film was obtained \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Electrode** & **Method** & **Linear Range (mol L\({}^{-1}\))** & **LOD (mol L\({}^{-1}\))** & **References** \\ \hline Graphite electrodes & DPV & \(1\times 10^{-8}\)\(-\)\(2.5\times 10^{-7}\) & \(3.5\times 10^{-8}\) & [52] \\ SHPD/CNT/CPE & DPV & \(6\times 10^{-7}\)\(-\)\(6\times 10^{-8}\) & \(2\times 10^{-9}\) & [53] \\ UO\({}_{2}\)\({}^{2+}-\)PME/CCE & FIP & \(1\times 10^{-7}\)\(-\)\(1\times 10^{-1}\) & \(5.4\times 10^{-8}\) & [54] \\ UO\({}_{2}\)\({}^{2+}-\)DCQ-VP & ISE & \(2.0\times 10^{-8}\)\(1.0\times 10^{2}\) & \(2.0\times 10^{8}\) & [49] \\ MIIP/Fe\({}_{3}\)O\({}_{4}\)@SiO\({}_{2}\)/MCPE & DPV & \(1\times 10^{-9}\)\(-\)\(2\times 10^{-7}\) & \(3.23\times 10^{-10}\) & This work \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of this method with other electrochemical methods for the determination of UO\({}_{2}\)\({}^{2+}\). \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**Added (\(\upmu\)M)**} & \multicolumn{3}{c}{**Detected by This Method**} \\ \cline{3-5}  & & **Found (\(\upmu\)M)** & **Recovery (\%)** & **RSD (\%)** \\ \hline Soil 1 & 0.10 & 0.103 & 103 & 1.69 \\ Soil 2 & 0.10 & 0.970 & 97 & 2.01 \\ Soil 3 & 0.10 & 0.101 & 101 & 2.41 \\ Water 4 & 0.15 & 0.156 & 104 & 1.25 \\ Water 5 & 0.15 & 0.147 & 98 & 3.06 \\ Tap water & 0.10 & 0.950 & 95 & 2.15 \\
0.15 & 0.146 & 97 & 1.03 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The MIIP/Fe\({}_{3}\)O\({}_{4}\)@SiO\({}_{2}\)/MCPE sensor applied to UO\({}_{2}\)\({}^{2+}\) analysis and determination in actual samples (\(n=6\)). by embedding the magnet material inside the carbon paste electrode, allowing the polymeric microspheres to be simply immobilized to the electrode surface under the action of an applied magnetic field without the need for a complicated process. Moreover, it can solve the problem of interference caused by a series of electrochemical experiments on MIIP/Fe3O4@SiO2/MCPE in the background solution (such as template shedding) to minimize the impact, thereby rendering a stable and intact IIP structure on the electrode surface. Due to its unique recognition characteristics, the IIP-modified carbon paste electrode material is highly selective for the determination of uranyl in the presence of common interfering ions. To sum up, the sensor has the advantages of low cost, simple preparation, fast analysis, high sensitivity, good stability, and excellent reproducibility, which can be applied in real samples. In addition, the new sensor developed in the present study also lays a certain foundation for the determination of other metal ions.