Screening combinatorial libraries of molecularly imprinted polymer films casted on membranes in single-use membrane modules

A new and fast technique for screening combinatorial libraries of molecularly imprinted polymers is presented. The procedure is based on commercially available membrane modules which are rinsed with pre-polymerization imprinting mixtures. After the in situ polymerization and generation of MIP films on the PTFE membranes within the modules, the membranes are evaluated in terms of affinity towards the target molecule (template) R-(-)-phenylbutyric acid. Therefore, after template extraction from the freshly produced membranes a solution of this target molecule is flushed through the module. By analyzing the remaining analyte concentration in the permeate, the amount of analyte adsorbed on the membrane can be calculated and related to specific interactions with the molecular imprints. By this means, optimized recipes in terms of cross-linker to template ratios could be obtained in combination with the optimal porogen, when screening p-divinylbenzene or ethylene glycol dimethacrylate as cross-linker and porogens like acetonitrile, dimethylsulfoxide and methanol.     

Synthesis and characterization of a molecularly imprinted polymer and its application as SPE enrichment sorbent for determination of trace methimazole in pig samples using HPLC-UV

A novel molecularly imprinted polymer that could be applied as enrichment sorbent was prepared using methimazole (MMZ) as the template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker. Though evaluated by static, kinetic and competitive adsorption tests, the polymer exhibited high adsorption capacity, fast kinetics and good selective ability. A method for determination of trace MMZ was developed using this polymer as enrichment sorbent coupled with high performance liquid chromatography focusing on complex biological matrices. Under the optimum experimental conditions, the MMZ standard is linear within the concentration range studied, that is, from 0.5 μg L⁻¹ to 150 μg L⁻¹ (r² = 0.9941). Lower limits of detection (LOD, at S/N = 3) and quantification (LOQ, at S/N = 10) in pig samples were 0.63 μg kg⁻¹ and 2.10 μg kg⁻¹ for kidney, 0.51 μg kg⁻¹ and 1.70 μg kg⁻¹ for liver, 0.56 μg kg⁻¹ and 1.86 μg kg⁻¹ for muscle, respectively. Recoveries and relative standard deviation (RSD, n = 9) values for precision in the developed method were from 71.14% to 88.41% and from 2.53% to 6.18%.