铑(III)离子印迹聚合物的制备及其作为吸附材料的应用探索

以RhCl63-为模板,丙稀酰胺(AM)为功能单体,甲基丙烯酸乙二醇酯(EGDMA)为交联剂,采用分子印迹技术合成了一系列铑离子印迹聚合物(ⅡPs);研究了聚合条件和聚合方法对ⅡPs吸附性能的影响。结果发现,在模板、功能单体和交联剂的加入摩尔比为1:2:40时,用沉淀聚合法制备的铑离子印迹聚合物(ⅡP2)具有较高的吸附容量和最好的印迹效果。该印迹聚合物不仅可重复多次使用,而且在Rh(Ⅲ)与Pd(Ⅱ)、Pt(Ⅳ)、Ru(Ⅲ)、Ir(Ⅳ)、Cu(Ⅱ)、Ni(Ⅱ)及Fe(Ⅲ)之间的吸附选择性系数均在10以上,将其作为吸附材料用于分离富集添加了Rh(Ⅲ)的河水样品中的Rh(Ⅲ),回收率在90%左右,相对标准偏差在5.0%以下。     

Molecularly Imprinted Ion-Exchange Resin for Fe3+

Abstract

Ion exchange resins selective for the sequestration of Fe³⁺ from aqueous solutions containing citrate were prepared by the molecular imprinting technique. Sorption characteristics of imprinted resins prepared with high (85 mole%) and low (3 mole%) amounts of covalent cross‐linking were examined. Experiments to determine loading capacity and selectivity, relative to several metal ions of physiological significance, were performed. The Fe³⁺ capacity of the highly cross‐linked resin was larger but the selectivity was lower.     

Synthesis and Evaluation of a Molecularly Imprinted Polymer for Solid Phase Extraction of Ethopabate from Chicken Tissue

In this paper the development and evaluation of a molecularly imprinted polymer (MIP) for ethopabate is described. Ethopabate (ETP), 4-acetamido-2-ethoxybenzoic acid methyl ester, is one of the antibiotics which is used as coccidiostat in poultry feeds. In the present study, two widely used functional monomers, methacrylic acid (MAA) and 4-vinylpyridine (4-VP) were compared theoretically and experimentally as the candidates for MIP preparation. Hyperchem software was employed to estimate binding energies between ETP and functional monomers and batch rebinding experiments were performed to study the binding characteristics of the polymers. The results showed that MAA is a better functional monomer to prepare MIP. UV/Vis and NMR spectroscopy were used as two common tools to study the interactions between ETP and MAA in the pre-polymerization mixture. Liquid chromatography experiments showed that the prepared MIP has recognition capability toward ETP in comparison with other structurally related compounds. The ETP-imprinted polymer was further applied for selective solid phase extraction (SPE) of ETP from a chicken tissue sample. The extraction yield of ETP was found to be quantitative (87 ± 3%) and the LOD and LOQ based on 3 and 10 times of the noise of HPLC profile were 0.05 and 0.32 ng ml^?1, respectively. It was confirmed that the binding ability of the prepared MIP for ETP was essentially sufficient in the presence of other compounds coexisting in tissue sample. Therefore, as a selective and efficient solid phase material, ETP-imprinted polymer has a high potential application in the analysis of residues of this antibiotic in chicken tissue samples.     

A Zipper‐Like On/Off‐Switchable Molecularly Imprinted Polymer

A zipper‐like on/off‐switchable molecularly imprinted polymer is reported. This unique imprinted polymer was composed of template‐imprinted polymeric networks that incorporate zipper‐like interactions between poly(acrylamide) (PAAm) and poly(2‐acrylamide‐2‐methyl propanesulfonic acid) (PAMPS). This polymer showed marginal recognition ability towards the imprint species under low temperature conditions, due to the interpolymer interaction between PAAm and PAMPS, which inhibited access to the imprinted networks. In contrast, at relatively high temperatures (such as 40 °C), the polymer demonstrated significant molecular recognition ability towards the imprint species resulting from the dissociation of the interpolymer complexes of PAAm and PAMPS, which enabled access to the imprint networks. Unlike previously reported PNIPAm‐based imprinted polymers, which demonstrate alterable molecular recognition simply because of the thermosensitive hydrophilicity/hydrophobicity of PNIPAm, this polymer employed a zipper‐like supramolecular architecture between PAAm and PAMPS, thereby enabling switchable molecular recognition.     

Design of molecularly imprinted polymer grafts with embedded gold nanoparticles through the interfacial chemistry of aryl diazonium salts

A novel strategy is described for the preparation of highly sensitive molecularly imprinted (MIPs) sensors for dopamine. It combines mercaptobenzene diazonium salt as a coupling agent for immobilizing gold nanoparticles to gold electrodes and benzoyl benzene diazonium salt as photoinitiator of radical polymerization at the said gold nanoparticle-decorated gold electrodes. The MIP films were prepared by surface-initiated photopolymerization (SIPP) of methacrylic acid (MAA) as functional monomer (F) for dopamine (DA) the template molecule (T), and ethylene glycol dimethacrylate (EGDMA), the crosslinker (C). Dimethylaniline was employed as a hydrogen donor. The specificity and selectivity were demonstrated by square wave voltammetry (SWV). The detection limit was 0.35 nmol L^-1 (0.054 ng mL⁻¹). The sensor layers are stable and adherent to the surface through aryl layers. The originality and advantage of the process lie in the use of aryl diazonium salt as coupling agents for anchroring nanoparticles and MIP layers to the electrode surface in a simple and efficient way which ensures high sensing performance together with good surface-MIP adhesion. The same strategy can be extended to a broad range of templates.     

The influence of polymer morphology on the performance of molecularly imprinted polymers

This is the first in-depth study examining the effect of morphology on the performance of 2-aminopyridine (2-apy) imprinted polymers. A series of polymers were prepared by varying the amount of crosslinking monomer (EGDMA) whilst the other polymer components remained constant. Physical characterisation was carried out using conventional techniques, such as nitrogen sorption porosimetry and solvent swelling studies. The use of a novel thermal desorption GC-MS technique suggested higher levels of polymer degradation with prolonged exposure to elevated temperatures for those polymers formed with lower amounts of EGDMA. The thermal desorption GC-MS profiles obtained correlated with the physical characteristics of the polymers, where higher levels of polymer bleed was found to occur with larger average pore diameters. Polymer physical characteristics were also found to correlate with the binding parameters (number of binding sites and polymer-template association energy) obtained from the Langmuir-Freundlich Isotherm (L-FI) and affinity distribution spectra (AD). The flexibility of the polymers formed from lower amounts of EGDMA combined the swelling effect of the solvents on the polymers resulted in an increase in affinity, which was both specific and non-specific in nature.     

Directly fast detection of digoxin in the serum sample by the synthetic receptor sensor

A novel biosensor (the synthetic receptor sensor) employing the molecular imprinted technology for the digoxin analysis is investigated. The molecularly imprinted polymer (MIP) modified electrode can specifically bind to the analyte in the sample without sample pretreatment. The digoxin analyzed by the MIP sensor was carried out in 1 mM K₃Fe(CN)₆ solution with the cyclic voltammetry. In the system, the K₃Fe(CN)₆³⁻/Fe₂(CN)₆⁴⁻ redox couple was taking place. When the solution contains the digoxin, the MIP on the electrode will bind the digoxin. Further the redox system is interrupted and the peak current is decreased according to the digoxin concentration increasing. Digoxin is a glycosylated steroid-like drug. It is important for the heart disease treatment. However, since the digoxin toxic level is low, the drug remains in the blood sample must be monitored frequently. The device possesses many advantages, such as high specific recognition properties, good chemical and mechanical stability, simplicity and low cost of preparation, sensitive and label free determination. The reproducibility is good (CV < 5). The linear relationship between the digoxin concentration and the current is 1.28–128 nM, and a detection limit of 1.28 nM is achieved. The detection time is less than 5 min.     

分子印迹聚合物的设计与制备

对分子印迹聚合物的设计、制备及其特性以及分子印迹技术的未来发展方向进行简要评述。过程及方法：概述了分子印迹技术的原理和特点，重点介绍了分子印迹聚合物的制备和特性，最后分析了分子印迹技术目前存在的一些突出问题。结果及应用范围：作为一种制备具有亲和性和选择性高、稳定性好的分子印迹聚合物的技术，分子印迹以其简便、通用和高效等特点吸引了研究者的广泛兴趣。分子印迹聚合物在分离分析、仿生传感器和模拟酶催化等领域将具有重要的应用前景。     

The preparation of molecularly imprinted poly(o‐phenylenediamine) membranes for the specific O,O‐dimethyl‐α‐hydroxylphenyl phosphonate sensor and its characterization by AC impedance and cyclic voltammetry

A molecularly imprinted polymer (MIP) membrane for sensing O,O‐dimethyl‐α‐hydroxylphenyl phosphonate (DHP) has been prepared by electropolymerizing o‐phenylenediamine on the glassy carbon electrodes in the presence of DHP. Optimization studies with the aim to enhance insulating properties and response kinetics of the polymer membrane were carried out with respect to template molecular concentration, the monomers concentration, the polymer membrane thick and scan rate. Cyclic voltammetry and electrochemical impedance have been used to characterize the behavior of MIP polymer membrane. The capacitive measurements were also certified the imprinting effect of the polymer layers. The experimental results showed that DHP imprinted polymer has better recognition property for the template than that of a blank polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2222–2227, 2006