Electrochemical tolazoline sensor based on gold nanoparticles and imprinted poly-o-aminothiophenol film

Amperometric detection of tolazoline (TL) was carried out on a gold nanoparticles (AuNPs)/poly-o-aminothiophenol (PoAT)-modified electrode by a molecular imprinting technique and electropolymerization method. The modification procedure was characterized via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The recognition between the imprinted sensor and target molecule was observed by measuring the variation of amperometric response of the oxidation-reduction probe, K₃Fe(CN)₆ on electrode. Under the optimal experimental conditions, the peak currents were proportional to the concentrations of tolazoline in two ranges of 0.05-5.0 μg mL⁻¹ and 5.0-240 μg mL⁻¹ with the detection limit of 0.016 μg mL⁻¹. Meanwhile the prepared sensor showed sensitive and selective binding sites for tolazoline. The enhancement of sensitivity was attributed to the presence of AuNPs which decreased the electron-transfer impedance.     

分子印迹电化学传感器检测链霉素

为实现链霉素的快速、灵敏测定,将特异性强的分子印迹技术与检测灵敏度高的电化学检测方法结合,构建链霉素分子印迹电化学传感器。以链霉素为模板分子,吡咯为功能单体,利用电化学聚合方法制备分子印迹聚合物(MIP)膜。在最优化实验条件下,以铁氰化钾为探针,利用循环伏安法(CV)对链霉素进行定量测定及传感器性能研究。结果表明:传感器线性范围为5.00×10~(-8)～8.00×10~(-5)mol/L,最低检出限(LOD)为3.45×10~(-8)mol/L,为链霉素的测定提供了高效的方法。     

Direct synthesis of surface molecularly imprinted polymers based on vinyl–SiO2 nanospheres for recognition of bisphenol A

Molecularly imprinted polymers (MIP) with high performance in selectively recognizing bisphenol A (BPA) were prepared by using a novel and facile surface molecular‐imprinting technique. Vinyl‐functionalized, monodispersed silica spheres were synthesized by a one‐step emulsion reaction in aqueous solution. Then, BPA surface molecularly imprinted polymers (SMIP) were prepared by polymerization with 4‐vinylpyridine as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. Maximal sorption capacity (Q_max) of the resulting SMIP was up to 600 μmol g^?1, while that of nonimprinted polymers was only 314.68 μmol g^?1. Kinetic binding study showed that sorption capacity reached 70% of Q_max in 20 min and sorption equilibrium at 80 min. SMIP had excellent accessibility and affinity toward BPA, for the selectivity coefficients of SMIP for BPA in respect to phenol, p‐tert‐butylphenol, and o‐phenylphenol were 3.39, 3.35, and 3.02, respectively. The reusage process verified the SMIP owning admirably stable adsorption capacity toward BPA for eight times. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Electrochemical sensor prepared from molecularly imprinted polymer for recognition of TNT

We report herein an effective strategy for recognizing of 2,4,6‐trinitrotoluene (TNT) molecules at the surface of graphene polyaniline (PANI) nanocomposites. The imprinted template was synthesized using picric acid as a template analogue for the explosive. The recognition sites were generated by the extraction of the imprinting template from GN‐PANI‐molecularly imprinted polymer film. The morphology of preparing films was investigated using scanning electronic microscopy images. The differential pulse voltammograms and cyclic voltammograms were used for TNT detection. The results reported here could form the basis of a new strategy for preparing various polymer‐coating layers on PANI supports and the molecular imprinting techniques discussed could also find applications in the fields of separation and environmental monitoring. POLYM. COMPOS., 36:1280–1285, 2015. © 2014 Society of Plastics Engineers     

基于壳聚糖的分子印迹聚合物的制备和应用

壳聚糖具有良好的生物相容性和独特的分子结构,基于其制备的分子印迹聚合物因亲和性和选择性高、应用范围广等特点引起了广泛的关注。本文首先总结了壳聚糖和改性壳聚糖在分子印迹聚合物制备中的作用,然后介绍了壳聚糖分子印迹聚合物在环境污染治理、医药、蛋白质分离与识别、手性物质分离以及吸附功能成分等方面的应用,分析了壳聚糖分子印迹聚合物在各个应用领域的优缺点及发展方向。最后,从发展绿色分子印迹技术以及分子印迹技术与电化学传感器结合等层面对壳聚糖分子印迹聚合物的应用前景进行了展望。     

Electrochemical probing of selective haemoglobin binding in hydrogel-based molecularly imprinted polymers

An electrochemical method has been developed for the probing of hydrogel-based molecularly imprinted polymers (HydroMIPs) on the surface of a glassy carbon electrode. HydroMIPs designed for bovine haemoglobin selectivity were electrochemically characterised and their rebinding properties were monitored using cyclic voltammetry. The electrochemical reduction of bovine oxyhaemoglobin (BHb) in solution was observed to occur at −0.460 V vs (Ag/AgCl) in 150 mM phosphate buffer solution (PBS). When the protein was selectively bound to the MIP, the electrochemical reduction of oxyhaemoglobin could be observed at a similar peak potential of −0.480 V vs (Ag/AgCl). When analysing the non-imprinted control polymer (NIP) interfaced at the electrode, which contained no protein, the peak reduction potential corresponded to that observed for dissolved oxygen in solution (−0.65 V vs (Ag/AgCl)). MIP and NIP (in the absence of protein) were interfaced at the electrode and protein allowed to diffuse through the polymers from the bulk solution end to the electrode. It was observed that whereas NIP exhibited a protein response within 10 min of protein exposure, up to 45 min of exposure time was required in the case of the MIP before a protein response could be obtained. Our results suggest that due to the selective nature of the MIP, BHb arrival at the electrode via diffusion is delayed by the MIP due to attractive selective interactions with exposed cavities, but not the NIP which is devoid of selective cavities.     

Solid-phase extraction materials based on molecularly imprinted polymers for recognition of pyrethroids

A novel recognition material for detection of kinds of pyrethroids was successfully synthesized by molecular imprinting technology. 3-Phenoxybenzoic acid (PBA) usually could be the antigen to prepare the polyclonal antibody. In this work, the recognition material was prepared utilizing PBA as the template, methacrylicacid as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. The recognition material was characterized by atomic force microscope, adsorption equilibrium and selectivity experiments. The results showed that the recognition material has been successfully prepared and recognized four pyrethroids (fenpropathrin, deltamethrin, fenvalerate, and cyhalothrin). The recognition material was utilized as sorbents in solid-phase extraction for separation and detection of pyrethroids in practically samples. Under the optimal conditions, the recoveries were ranging from 74.3 to 111.0%. Therefore, novel materials for pyrethroids are very promising for future applications. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48919.     

Electrochemical copper (II) sensor based on chitosan covered gold nanoparticles

This study outlines a new sensing platform based on glassy carbon electrodes modified by gold nanoparticles (AuNPs) for the determination of heavy metal. A glassy carbon electrode was modified by chitosan stabilized AuNPs. AuNPs were prepared by reducing gold salt with a polysaccharide chitosan. Here, chitosan acted as a reducing/stabilizing agent. The AuNPs were characterized with UV–Visible absorption spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. Chitosan covered AuNPs were immobilized on the glassy carbon electrode for the determination of Cu (II) in aqueous solutions. The electrochemical determination of Cu (II) ions was performed using the differential pulse voltammetry technique. Some parameters for Cu (II) determination, such as pH, preconcentration time and electrolysis potential of Cu (II), were optimized. The detection limit was calculated as 5 × 10^?9 mol L^?1 by means of the 3:1 current-to-noise ratio. The interference of Cr(III), Fe(II), Ni(II), Pb(II), Mg(II), Zn(II), Ba(II) ions was investigated and showed a negligible effect on the electrode response. Recovery studies were carried out using tap water.     

Electrochemical determination of cysteine based on conducting polymers/gold nanoparticles hybrid nanocomposites

In this study, a hybrid nanocomposite consisting of a conducting polymer and gold nanoparticles (AuNPs) is fabricated onto a screen-printed carbon electrode (SPCE). A thin layer of poly(3,4-ethylenedioxythiophene) (PEDOT) is coated electrochemically on a bare SPCE; then, the nano-sized AuNPs are embedded by electrochemical deposition. The resultant SPCE/PEDOT/AuNPs-modified electrode is characterized by electrochemical methods, field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). The SPCE/PEDOT/AuNPs-modified electrode possesses great catalytic activity for the oxidation of cysteine in various pH buffer solutions (pH 2.0–8.0). The selectivity of the method is demonstrated by the separation of the oxidation peaks at up to 240 mV for cysteine and glutathione in pH 6.0 buffer solutions. The effects of the oxidizable interferences are also investigated. Flow-injection amperometry is performed for 0.5–200 μM of cysteine in pH 4.0 buffer solutions, and a linear calibration plot with a slope of 0.115 μA/μM is obtained. The detection limit (S/N = 3) is 0.05 μM. Additionally, the proposed methods obtain satisfactory results in the detection of cysteine-containing medicine samples.     

Synthesis and optimization of molecularly imprinted polymers for quercetin

Molecularly imprinted polymers (MIPs) were synthesized through solution polymerization using quercetin as the template molecule, N‐vinylpyrrolidone and acrylic acid as functional monomers, N,N′‐methylenebiacrylamide as crosslinker and the redox system L ‐ascorbic acid and hydrogen peroxide as initiator in the porogen of ethanol and water. During the optimization process an interference compound, genistein (5,7,4′‐trihydroxy isoflavone), which possesses the same skeleton and functional groups as quercetin, was adopted to optimize the preparation conditions, and the separation degree of the MIP to quercetin and genistein was chosen to optimize each factor. The synthesized MIP under optimal conditions showed a specific recognition of quercetin from a mixture of quercetin and genistein. Thereafter, the structure of the MIP was comparatively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer–Emmett–Teller analysis using non‐imprinted molecular polymers as control. In addition, the kinetics of the adsorption process were also studied, and Scatchard analysis revealed that heterogeneous binding sites were formed in the polymers. Copyright © 2012 Society of Chemical Industry     

三硝基甲苯分子印迹电化学传感器的制备和应用

以三硝基甲苯（TNT）为模板分子,甲基丙烯酸（MAA）为功能单体,采用乳液聚合法制备TNT的分子印迹聚合物（MIPs）。将制备的MIPs分散在溶剂中,通过表面涂覆法制备出检测TNT的分子印迹电化学传感器。紫外光谱表明TNT与MAA之间存在相互作用力,有助于形成结构稳定、亲和性强的MIPs。利用扫描电镜观测不同制备条件下印迹聚合物的表观形貌,发现溶剂用量为30mL、乳化剂用量为12mg时制备的聚合物形貌较优异。吸附实验表明MIPs对TNT的吸附量随着TNT初始浓度的增加而增加,140min后达到最大吸附量的95%。MIPs对TNT的分离常数远大于RDX和DNT,对RDX和DNT的选择性系数均达到4.4以上,说明MIPs对TNT有较好的选择性吸附能力。铁氰化钾探针实验和对TNT的响应曲线验证了电化学传感器的成功制备,该传感器富集3min就达到了最大电流值的94%,5min内达到吸附平衡。TNT浓度在0.1~5mg/mL的范围内与峰电流有良好的线性关系,检出限为0.06mg/mL。MIPs传感器对TNT的电流响应分别为DNT和RDX的3.13倍、3.27倍,说明其对TNT分子具有很强的特异性识别能力。     

基于对氨基苯酚的芦丁分子印迹电化学传感器的制备及应用

在GCE表面构建了一种新型的基于对氨基苯酚(p-aminophenol,p-AP)的芦丁分子印迹电化学传感器并对芦丁(rutin,RT)进行检测研究.考察了制备条件、检测条件对检测的影响,并进行了阻抗表征,最后研究了芦丁浓度与电流响应的关系.结果表明,最佳沉积圈数是12圈;p-AP与芦丁最佳质量浓度比为1:8;最佳洗脱...     

香草醛分子印迹聚合物的制备及其性能研究

以香草醛为模板分子,二甲基丙烯酸乙二醇酯(EDMA)为交联剂,甲基丙烯酸(MAA)为功能单体,采用悬浮聚合法和本体聚合法制备了香草醛分子印迹聚合物。利用扫描电镜、平衡吸附实验、选择性吸附实验等,探讨了两种聚合方法制备出的分子印迹聚合物的性能。结果表明,悬浮聚合法制备的分子印迹聚合物粒径分布更均匀,选择吸附性能更好,更适用于分离材料。     

Synthesis and characterization of high selective molecularly imprinted polymers for bisphenol A and 2,4-dichlorophenoxyacetic acid by using supercritical fluid technology

Molecularly imprinted polymers (MIPs) have been extensively used in chemical and biochemical related areas due to their high molecular recognition affinity and selectivity for the target molecule. On the other hand, supercritical polymerization is relatively novel technique, which can be applied in the polymerization without hazard organic solvent. This work introduces a supercritical fluid polymerization technique for preparation of MIP particles. The adsorption properties of prepared MIP particles are also investigated. The MIPs were prepared with methyl methacrylate (MMA) as a third monomer, methacrylic acid (MAA) as a functional monomer, templates (bisphenol A (BPA) and 2,4-dichlorophenoxyacetic acid (2,4-D)), methyl methacrylate (MMA) as a third vinyl monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. Equilibrium binding experiments are conducted to evaluate the binding characteristics of MIPs and templates (BPA and 2,4-D). The Scatchard plot analysis demonstrates that two classes of binding sites are formed with the equilibrium dissociation constants. The adsorption ability of the MIPs was also evaluated by measuring the adsorbed amounts of a similar imprinted template structure, the selectivity factor (α), and the imprinting-induced promotion of binding (IPB).     

Preparation of molecularly imprinted fluorescence sensor based on carbon quantum dots via precipitation polymerization for fluorescence detection of tetracycline

A facile and effective method was proposed to prepare the molecularly imprinted fluorescence sensor with carbon quantum dots, which were modified vinyl groups by acrylic acid on the surface. The obtained fluorescence composite material was investigated by transmission electron microscope and Fourier transform infrared spectra. After the experimental conditions were optimized, a linear range of 1.0–60 μmol L⁻¹ was obtained and the detection limit was 0.17 μmol L⁻¹. The novel fluorescence sensor can be successfully used to detect tetracycline in real samples. This study provides a convenient strategy for selective recognition and rapid detection of tetracycline in the complex environment.     

表面印迹聚合物的制备与吸附性能

以L-色氨酸作为模板分子,丙烯酰胺为功能单体,N,N'-亚甲基双丙烯酰胺为交联剂,通过在聚甲基丙烯酸甲酯多孔基质球表面复合印迹层,制备了L-色氨酸表面印迹聚合物微球(SMIPs),探索了不同比表面积基质球及添加丙烯腈对SMIPs吸附性能的影响,结果表明基质球比表面积为432.0m~2/g时,SMIPs对L-色氨酸的吸附量较高;当n(AN):n(L-trp):3:1时,SMIPs的综合吸附性能较好.     

Positron annihilation lifetime spectroscopy of molecularly imprinted hydroxyethyl methacrylate based polymers

Radiation-induced molecular imprinting of d-glucose onto poly(2-hydroxyethyl methacrylate) (HEMA) matrix was achieved to create three-dimensional cavities to recognize and bind glucose. Molecularly imprinted polymers (MIPs) were synthesized with different types of crosslinkers and varying amounts of template molecule in an attempt to elucidate the impact of imprint quantities on the effectiveness of imprinting technique. The crosslinking agents used in this study were diethylene glycol diacrylate (DEGDA), triethylene glycol dimethacrylate (TEGDMA) and polypropylene glycol dimethacrylate (PPGDMA) in the order of increasing chain length. Crosslinking agent concentration in the polymerization mixture (monomer, crosslinking agent and template) covered a range of 10, 20, 30, and 70 mol%. The mole ratio of template molecule, d-glucose to functional monomer, HEMA, was kept either as 1:3 or 1:6. The absorbed dose varied from 1 to 15 kGy. Control polymers were synthesized with exactly the same composition in the absence of d-glucose. Cavity sizes of MIPs were investigated by positron annihilation lifetime (PAL) measurements. A sandwich arrangement (sample-source-sample) was used. PAL experiments were carried out using a conventional fast-fast coincidence system having a time resolution (FWHM) of about 280 ps. Free-volume hole radii of samples were investigated in their dry and fully water swollen state.The results obtained from a systematic study of the effects of concentration and molecular size of the crosslinking agents, template to monomer ratio and irradiation dose experiments suggest that control of cavity size is feasible in nanometer scale by the optimization of these parameters revealed by means of (PAL) spectroscopy technique.     

磁性粉煤灰空心微珠表面印迹聚合物选择性识别头孢氨苄

利用共沉淀法制备了粉煤灰空心微珠磁性复合材料（MFACs）,以乙烯基改性的MFACs为基质材料,利用乳液聚合法制备磁性粉煤灰空心微珠表面印迹聚合物（MMIPs）。通过SEM、FT-IR、TGA、XRD和VSM等方法对其物理化学性质进行表征,其比表面积123.65 m²·g^-1,且具有较好的热稳定性、超顺磁性（M_s=12.155 emu·g^-1）。通过系列吸附实验研究表明,Langmuir等温模型能较好地拟合MMIPs对头孢氨苄（cefalexin,CFX）的吸附平衡数据,25℃时MMIPs的单分子层吸附容量为69.55 mg·g^-1。准二级动力学模型能较好地描述MMIPs对CFX吸附动力学行为,选择性实验研究表明,MMIPs对CFX具有较好地选择识别性。结合高效液相色谱分析技术,MMIPs已成功应用于环境样品中痕量CFX的分离/富集。     

Extraction and determination of malachite green from aquatic products based on molecularly imprinted polymers

Molecularly imprinted polymers (MIPs) were synthesized using malachite green (MG) as template, and methacrylic acid/sodium methacrylate as composite monomers. The equilibrium dissociation constant and apparent maximum adsorption capacity of the MIPs reach 12.2 mg·L^?1 and 3.2 mg·g^?1, respectively. The MIPs demonstrate excellent recognition ability due to high-affinity sites constructed by the electrostatic interaction and hydrogen bonds between template and composite monomers. The MIPs were successfully employed for the detection of MG residue in aquatic products coupled with high-performance liquid chromatography (HPLC) with a detection limit of 0.57 μg·kg^?1.     

Preparation and adsorption selectivity of rutin molecularly imprinted polymers

Molecularly imprinted polymer (MIP) for Rutin had been prepared through solution polymerization by redox initiation. The effects of monomers, crosslinker, initiators, polymerization time, and temperature on adsorption selectivity for Rutin were investigated and optimized. The structure and surface morphology of MIP were evaluated by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The synthesized MIP under the optimal conditions showed a specific recognition of Rutin from the mixture of Rutin and Isorhamnetin. And the maximal separation degree of Rutin was 5.0. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011