INSTITUTUL NAÅ¢IONAL DE CERCETARE-DEZVOLTARE - ICECHIM

2. Multifunctional materials and nanocomposites - PCOMPETITIVE BATCH REBINDING IN DIOSGENIN MOLECULARLYIMPRINTED POLYMERS (D-MIPS)Stefan-Ovidiu Dima a,b , Andrei Sarbu a , Tanase Dobre ba National Research and Development Institute for Chemistry and Petrochemistry ICECHIM,Splaiul Independentei 202, Bucharestb Politehnica University of Bucharest, Splaiul Independentei 313, BucharestSection 2: Multifunctional materials and nanocompositesThe binding capacity of diosgenin imprinted (D-MIPs) and non-imprinted polymers wasevaluated from batch rebinding studies. The conditions were: 0.1 g of pearls type MIPAN:AA 80:20 in 8 mL solution with three concentrations: 0.2%, 0.4% and 0.6% of templateand competitors in ethanol. Three competitor molecules were chosen for crossreactivity testsagainst the template (diosgenin – D): inulin (I), hydrocortisone (HC) and stigmasterol (ST).Fig. 1. Overlaid chromatograms of 0.2% solutions (D+ST+HC+I)at four different adsorption moments (0, 0.1, 0.3 and 0.5h).Fig. 2. The selectivity of the binding sites forthe template (diosgenin), as determined in thesolid phase.The adsorption capacity B (g i / g polymer ) was calculated with eq. (1), in which c i and c f(g/L) were the initial and final concentrations of specie “i” in solution (were “i” can bereplaced with D, ST, HC and I), V s (L) was the volume of the initial solution and m p (g) wasthe quantity of polymer taken into account. The affinity of specie “i” for the binding sites canbe calculated with the eq. (2), where ΣB represent the sum of all adsorbed species in MIP.( ci- cfB =mp) × Vs, (1)BiAi = , (2)BThe crossreactivity based on the imprinting effect might be categorized into four classes:(i) high binding for the template (affinity 54% for D), (ii) intermediate crossreactivity forsubstances with similar structure and similar functional groups (affinity 31% for HC), (iii)low-intermediate crossreactivity for substances with similar structure (affinity 11% for ST)and (iv) low binding for structurally non-related compounds (affinity 4%I).å