An Atrazine Molecularly Imprinted Polymer Synthesized Using a Cooling-Heating Method with Repeated Washing: Its Physicochemical Characteristics and Enhanced Cavities

Abstract

An atrazine molecularly imprinted polymer (MIP) has been successfully produced via a coolingheating method with repeated washing process. A template (atrazine) was incorporated into a prepolymerization solution containing a functional monomer (methacrylic acid), a cross-linker (ethylene glycol dimethacrylate), and an initiator (benzoyl peroxide). The pre-polymerization solution was cooled in a refrigerator at -5°C for 60 min. and heated in an oven at 70°C for 150 min. The template removal process was conducted through a repeated washing process to increase the effectiveness of the cavities formation. The FTIR spectrum of the MIP showed that the peaks of amine group decrease significantly, indicating that the concentration of atrazine decreases drastically. HPLC was used to determine accurately the concentration of atrazine and the chromatogram of the MIP confirmed that there is no atrazine left. The repeated washing process was therefore better than the single washing process with 3% of atrazine left. In addition, the MIP obtained by the repeated washing process had the number of cavities of 780, which is higher than that produced by the single washing process as analyzed from SEM images. From the Scatchard plots, it was found that the equilibrium dissociation constant KD and the maximum number of binding sites Bmax, which is written as (KD; Bmax), of the MIP obtained by the repeated washing process is (7.1 μM; 14.9 mmol/g), respectively. These values are higher than those of the MIP produced by the single washing process.