## Materials and Methods
### Binding Experiments  
Binding studies were conducted to evaluate the adsorption performance of MIPs and NIPs for gossypol. In the study, the UV absorption peak at 373 nm was chosen for the quantitative analysis. By comparing the change of absorbance value before and after the uptake, the binding capacity of each material was obtained. In the kinetic adsorption experiments, 10 mg of MIPs or NIPs were added to 5.0 mL of the gossypol solution in methanol at an initial concentration (\(C_{0}\), mg\(\cdot\)L\({}^{-1}\)) of 300 mg\(\cdot\)L\({}^{-1}\) and were shaken for different time intervals ranging from 0 min to 900 min (MIP1 and NIP1) and 0 min to 90 min for MIP2, MIP3, NIP2, and NIP3. Then, the supernatants and polymers were separated using syringe filters (0.2 \(\upmu\)m, PTFE), and the concentrations of gossypol in the supernatant (\(C_{t}\), mg\(\cdot\)L\({}^{-1}\)) were measured by UV-Vis spectrometry following a reported procedure [9]. The adsorption capacity (\(Q_{t}\), mg\(\cdot\)g\({}^{-1}\)) at given times was calculated according to Equation (1):  
\[Q_{t}=\frac{(C_{0}-C_{t})V}{m} \tag{1}\] \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Polymer** & **Template** & **FM** & **Cross-linker** & **Initiator/Catalyst** & **Support** & **Solvent** \\  & **(mmol)** & **(mmol)** & **(mmol)** & **(g)** & **(mL)** \\ \hline MIP1 a & Gossypol & DMAEMA & EGDMA & AIBN & CH\({}_{2}\)Cl\({}_{2}\) \\  & (0.083) & (1.0) & (5.0) & (0.27 mmol) & & (4.0) \\ NIP1 a & & DMAEMA & EGDMA & AIBN & CH\({}_{2}\)Cl\({}_{2}\) \\  & & (1.0) & (5.0) & (0.27 mmol) & & (4.0) \\ MIP2 b & Gossypol & APTES & TEOS & 1.0 mol L\({}^{-1}\) HAc & activated & Acotone \\  & (0.083) & (1.25) & (2.6) & (0.15 mL) & silica (0.058) & (3.0) \\ NIP2 b & & APTES & TEOS & 1.0 mol L\({}^{-1}\)HAc & activated & Acotone \\  & & (1.25) & (2.6) & (0.15 mL) & silica (0.058) & (3.0) \\ MIP3 b & Gossypol & APTES & TEOS & 1.0 mol L\({}^{-1}\)HAc & Acotone \\  & (0.083) & (1.25) & (2.6) & (0.15 mL) & (3.0) \\ NIP3 b & & APTES & TEOS & 1.0 mol L\({}^{-1}\)HAc & Acotone \\  & & (1.25) & (2.6) & (0.15 mL) & (3.0) \\ \hline \hline \end{tabular}  
* a: bulk polymerization carried out at 65 \({}^{\circ}\)C for 24 h; b: sol –gel surface imprinting and sol-gel process carried out at room temperature (RT) for 24 h.
* NIP = non-imprinted polymer, MIP = molecularly imprinted polymers, DMAEMA = dimethylaminoethyl methacrylate, EGDMA = ethylene glycol dimethacrylate, AIBN = 2,2-azobis(isobutyronitrile), APTES = (3-aminopropyl) triethoxysilane, TEOS = tetraethoxysilane.  
\end{table} 
Table 1: Polymerization conditions for the preparation of bulk polymerization and sol-gel surface layer imprinting. where \(V\) (L) is the volume of gossypol solution, and \(m\) (g) is the weight of the absorbents. In the adsorption isothermal experiments, 10 mg of MIPs or NIPs were added to 5.0 mL of gossypol solutions in methanol at various concentrations ranging from 200 mg\(\cdot\)L\({}^{-1}\) to 2000 mg\(\cdot\)L\({}^{-1}\) and were shaken for 12 h (MIP1 and NIP1). Ten mg of MIPs or NIPs were added to 5.0 mL of gossypol solutions in methanol at various concentrations ranging from 110 mg\(\cdot\)L\({}^{-1}\) to 1600 mg\(\cdot\)L\({}^{-1}\) for MIP2, MIP3, NIP2, and NIP3 and were shaken for 6 h to ensure adsorption equilibrium could be reached. The supernatants and polymers were separated by a syringe filter (0.2 \(\upmu\)m, PTFE), and the supernatants were analyzed to determine the remaining concentration (\(C_{\mathrm{e}}\), mg\(\cdot\)L\({}^{-1}\)) using UV-Vis spectrometry (Shimadzu, Kyoto, Japan) [9]. The equilibrium adsorption capacity (\(Q_{\mathrm{e}}\), mg\(\cdot\)g\({}^{-1}\)) was calculated according to Equation (2):  
\[Q_{\mathrm{e}}=\frac{(C_{0}-C_{\mathrm{e}})V}{\mathrm{m}} \tag{2}\]  
Two structurally similar analogs of ellagic acid and quercetin were chosen for the selectivity study. Ten mg of MIPs or NIPs were added to 5.0 mL of each analyte solution in methanol (200 mg\(\cdot\)L\({}^{-1}\) of gossypol, ellagic acid, and quercetin).