Core-shell magnetic-modified molecular imprinted polymer (Fe3O4@SiO2@MIP) for dihydroartemisinin recognition and separation

Dihydroartemisinin (DHA) is an artemisinin derivative compounds that employs as malaria drug. Extraction and purification artemisinin derivatives by liquid extraction utilize organic solvent and results in mixtures of compounds requiring further purification process. In this study, core-shell magnetic molecular imprinted polymer (Fe3O4@SiO2@MIP) has been synthesized for DHA isolation. Methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) were employed as monomer and cross-linker, respectively. Fe3O4 was modified by tetraethyl orthosilicate (TEOS) to enhance stability and prevent aggregation. Nonimprinted polymer (Fe3O4@SiO2@NIP) was also prepared as a comparison. The Fourier transform infrared (FTIR) represented O-O stretching of O-O-C bond (1,2,4-trioxane ring) at 825 cm(-1) denoting that DHA has been successfully attached to MIP. Meanwhile, the morphology of Fe3O4@SiO2@MIP and Fe3O4@SiO2@NIP revealed uniform spherical-like form particle due to core-shell magnetic modification. The Brunaeur-Emmett-Teller (BET) revealed S-BET of Fe3O4@SiO2@MIP and Fe3O4@SiO2@NIP was 70.16 and 19.56 m(2) g(-1), respectively. The prepared materials owned a superparamagentic behavior as indicated by narrow loop and low remanence and coercivity. The binding study indicated that Fe3O4@SiO2@MIP and Fe3O4@SiO2@NIP were achieved optimum condition at pH 4, contact time 90 min and initial concentration 8 mg L-1 with adsorption capacity (q(exp)) 1.026 mg g(-1) for Fe3O4@SiO2@MIP and 0.806 for Fe3O4@SiO2@NIP. The selectivity of Fe3O4@SiO2@MIP was more than 60% in all over the ratio. The prepared MIP exhibited good selectivity toward DHA with imprinting factor (IF) 2.14 and selectivity coefficient (a) 3.43. The percent adsorption of Fe3O4@SiO2@MIP did not changed after three times adsorption-desorption cycles. The result exhibited that Fe3O4@SiO2@MIP could effectively be used for DHA separation.