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《Solid State Sciences》2012,14(7):777-781
TiO2 film imprinted by atrazine molecule at the surface of quartz crystal was prepared using molecular imprinting and surface sol-gel process. The molecularly imprinted TiO2 film was characterized by scanning electron microscopy and cyclic voltammetry, and the atrazine adsorption was investigated by quartz crystal microbalance (QCM) technique. In comparison with non-imprinted TiO2 film, the molecularly imprinted TiO2 film exhibits high selectivity for atrazine, better reversibility and a much higher adsorption capacity for the target molecule, the adsorption equilibrium constant estimated from the in situ frequency measurement is about 6.7 × 104 M−1, which is thirteen times higher than that obtained on non-imprinted TiO2 film. 相似文献
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We have developed a piezoelectric sensor for the determination of atrazine. It is based on the modification of a molecularly imprinted film of TiO2 that was placed on a quartz crystal via a surface sol?Cgel process. The resulting sensor exhibits high selectivity for atrazine, a re-usability that is better than that of other sensors, a response time of 3?min, a wider linear range (0.0005?C8?mM), and a lower detection limit (0.1???M). The analytical application of the atrazine sensor confirms the feasibility of atrazine determination. Graphical abstract
The response of QCM electrodes prepared by various methods to atrazine (pH 5.0). 相似文献
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Acetylsalicylic acid electrochemical sensor based on PATP-AuNPs modified molecularly imprinted polymer film 总被引:1,自引:0,他引:1
A novel electrochemical sensor based on molecularly imprinted polymer film has been developed for aspirin detection. The sensitive film was prepared by co-polymerization of p-aminothiophenol (p-ATP) and HAuCl(4) on the Au electrode surface. First, p-ATP was self-assembled on the Au electrode surface by the formation of Au-S bonds. Then, the acetylsalicylic acid (ASA) template was assembled onto the monolayer of p-ATP through the hydrogen-bonding interaction between amino group (p-ATP) and oxygen (ASA). Finally, a conductive hybrid membrane was fabricated at the surface of Au electrode by the co-polymerization in the mixing solution containing additional p-ATP, HAuCl(4) and ASA template. Meanwhile, the ASA was spontaneously imprinted into the poly-aminothiophenol gold nanoparticles (PATP-AuNPs) complex film. The amount of imprinted sites at the PATP-AuNPs film significantly increases due to the additional replenishment of ASA templates. With the significant increasing of imprinted sites and doped gold nanoparticles, the sensitivity of the molecular imprinted polymer (MIP) electrode gradually increased. The molecularly imprinted sensor was characterized by electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV). The linear relationships between current and logarithmic concentration were obtained in the range from 1 nmol L(-1) to 0.1 μmol L(-1) and 0.7 μmol L(-1) to 0.1 mmol L(-1). The detection limit of 0.3 nmol L(-1) was achieved. This molecularly imprinted sensor for the determination of ASA has high sensitivity, good selectivity and reproducibility, with the testing in some biological fluids also has good selectivity and recovery. 相似文献
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分子印迹膜电化学传感器检测土壤中莠去津 总被引:2,自引:0,他引:2
本文报道了一种对莠去津有识别特性的分子印迹膜的制备,即在含和不含模板分子(莠去津)的情况下,通过循环伏安技术在金电极表面沉积2-巯基苯并咪唑,制备了2-巯基苯并咪唑聚合膜.利用循环伏安法对印迹和非印迹膜行为进行了评价,对分子印迹膜的影响因素进行了筛选和优化.实验表明,该分子印迹膜对莠去津具有良好的选择性和灵敏度.莠去津的还原峰电流与莠去津的浓度在 1.2 ×10 - 8mal/L~8.0 ×10 - 5mol/ L 范围内具有良好的线性关系( r=0.99862),检出限可达 3.0 ×10 - 9mol/ L.将此传感器用于土壤中莠去津的测定,回收率在90.8% ~ 98.2%之间,取得了很好的结果. 相似文献
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Photo-lithographically impregnated and molecularly imprinted polymer thin film for biosensor applications 总被引:1,自引:0,他引:1
A voltammetric sensor for albuterol was investigated where we combined the techniques of microfabrication and molecular imprinting to construct on-chip devices using photoirradiation of cross-linkable polymers. Molecularly imprinted polymer was coated as a thin film onto the gold working electrode on chip and the analyte was directly quantified by differential pulse voltammetric measurements. 相似文献
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Nan Wu 《Analytica chimica acta》2009,653(1):103-967
A novel and highly selective optical sensor with molecularly imprinted polymer (MIP) film was fabricated and investigated. The optical sensor head employing a medium finesse molecularly imprinted polymer film has been fabricated and characterised. A blank polymer and formaldehyde imprinted polymer were using methacrylic acid as the functional monomer and the ethylene glycol dimethacrylate as a crosslinker. The transduction mechanism is discussed based on the changes of optical intensity of molecularly imprinted polymer film acting as an optical reflected sensor. Template molecules, which diffused into MIP, could cause film density, and refractive index change, and then induce measurable optical reflective intensity shifts. Based on the reflective intensity shifts, an optical reflection detection of formaldehyde was achieved by illuminating MIP with a laser beam. For the same MIP, the reflective intensity shift was proportional to the amount of template molecule. This optical sensor, based on an artificial recognition system, demonstrates long-time stability and resistance to harsh chemical environments. As the research moves forward gradually, we establish the possibilities of quantitative analysis primly, setting the groundwork to the synthesis of the molecular imprinted optical fiber sensor. The techniques show good reproducibility and sensitivity and will be of significant interest to the MIPcommunity. 相似文献
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Enantioselective sensor based on microgravimetric quartz crystal microbalance with molecularly imprinted polymer film 总被引:2,自引:0,他引:2
We report a novel quartz crystal microbalance sensor that provides enantioselectivity to dansylphenylalanine enantiomers by using a molecularly imprinted polymer film as a recognition element. The polymeric recognition thin film, imprinted with chiral dansyl-L-phenylalanine, was immobilised on a gold electrode modified with a photoactive precursor monolayer via a self-assembly process using photopolymerization. The fabricated sensor was able to discriminate between L- and D-dansylphenylalanine enantiomers in solution owing to the enantioselectivity of the imprinted sites. The enantiomeric composition of L- and D-enantiomeric mixtures could be quantitatively determined by the fabricated sensor. The detection limit is 5 micrograms mL-1 with a response range of 5-500 micrograms mL-1 at pH 10.0. The influence of the template concentration on the sensitivity and selectivity of the synthesised polymer membranes was investigated and optimised. The surface characteristics of the polymer coating were studied by varying the pH value of the buffer solution, and a convenient regeneration process was proposed to increase the reproducibility and reusability of the sensor by flushing with pH 2.0 buffer. The selectivity and recognition mechanism of the imprinted polymer film were studied with compounds that are structurally related to the template. The method presented in this work provides a novel means of preparing highly selective and sensitive chemical sensors via self-assembly and molecularly imprinting techniques. 相似文献
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Terminal alkynyl and azide groups are introduced on the surface of molecularly imprinted core-shell nanoparticles using precipitation polymerization. These clickable groups enable simple nanoparticle conjugation and surface modification under mild reaction conditions, opening new opportunities for nanoparticle-based assays and chemical sensing. 相似文献
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A novel amine-imide type conducting polymer, denoted as poly(PD-BCD), was molecularly imprinted on an indium-tin oxide (ITO) glass, with uric acid (UA) as the template and without any functional monomer. Intending to improve the imprinting efficiency, the polymer content was varied from 0.3 to 0.9 wt% during the preparation of the molecularly imprinted polymer (MIP), thereby varying the thickness of the polymer film; the content of UA as the template was maintained to be the same for all the films. The sensitivities of the thus prepared MIP electrodes were calculated to be more than 3-fold, compared to those of the corresponding non-MIP (NMIP) electrodes, which were obtained through the same method, however, without adding UA during their preparation. A polymer content of 0.6 wt% rendered the best performing MIP electrode, as judged by the imprinting efficiency and sensitivity of the electrode for UA. A linear relationship between steady-state currents and UA concentrations from 0 to 1.125 mM was obtained for both types of the sensors. The sensitivities of the MIP and the NMIP electrodes made with 0.6 wt% of polymer were calculated to be 24.72 and 6.63 μA mM−1 cm−2, respectively. The limit of detection (LOD) for this MIP was found to be 0.3 μM at a signal to noise ratio (S/N) of 3. This MIP electrode was used as a biosensor for the detection of UA in the presence of ascorbic acid (AA) in a sample containing these species in the same concentrations as those in a human serum. The selectivity of MIP electrode is higher than that of NMIP electrode, and the values are 28.76 and 8.85, respectively. The results are substantiated by using cyclic voltammetry (CV), linear sweep voltammetry, amperometry, and scanning electron microscopy. 相似文献
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We have investigated the effect of buffer solution composition and pH during the preparation, washing and re-loading phases within a family of acrylamide-based molecularly imprinted polymers (MIPs) for bovine haemoglobin (BHb), equine myoglobin (EMb) and bovine catalyse (BCat). We investigated water, phosphate buffer saline (PBS), tris(hydroxymethyl)aminomethane (Tris) buffer and succinate buffer. Throughout the study MIP selectivity was highest for acrylamide, followed by N-hydroxymethylacrylamide, and then N-iso-propylacrylamide MIPs. The selectivity of the MIPs when compared with the NIPs decreased depending on the buffer conditions and pH in the order of Tris > PBS > succinate. The Tris buffer provided optimum imprinting conditions at 50 mM and pH 7.4, and MIP selectivities for the imprinting of BHb in polyacrylamide increased from an initial 8:1 to a 128:1 ratio. It was noted that the buffer conditions for the re-loading stage was important for determining MIP selectivity and the buffer conditions for the preparation stage was found to be less critical. We demonstrated that once MIPs are conditioned using Tris or PBS buffers (pH7.4) protein reloading in water should be avoided as negative effects on the MIP's imprinting capability results in low selectivities of 0.8:1. Furthermore, acidifying the pH of the buffer solution below pH 5.9 also has a negative impact on MIP selectivity especially for proteins with high isoelectric points. These buffer conditioning effects have also been successfully demonstrated in terms of MIP efficiency in real biological samples, namely plasma and serum. 相似文献
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Evaluation of methods aimed at complete removal of template from molecularly imprinted polymers. 总被引:1,自引:0,他引:1
A Ellwanger C Berggren S Bayoudh C Crecenzi L Karlsson P K Owens K Ensing P Cormack D Sherrington B Sellergren 《The Analyst》2001,126(6):784-792
Polymers imprinted with clenbuterol were used to study the influence of various post-polymerization treatments [e.g., thermal annealing, microwave assisted extraction (MAE), Soxhlet extraction and supercritical fluid template desorption] on the bleeding of residual template. The aim of the study was to reduce the bleeding to levels that would allow the use of the materials as affinity phases for extraction of clenbuterol from bovine urine at concentrations below 1 ng ml-1. After treatment, the clenbuterol imprinted polymers were packed into solid-phase extraction columns and the bleeding was estimated by quantifying the amount of template released in 10 ml of methanol-acetic acid (9 + 1 v/v). This was followed by an assessment of selectivity and recovery in comparison with non-treated material. The lowest bleeding level was found after MAE using 100% trifluoroacetic acid for 3 x 20 min at 100 degrees C. The collected eluate contained in this case 3 ng ml-1 of clenbuterol. The same material was subsequently used for the extraction of clenbuterol from spiked bovine urine. The resulting selectivity and recovery were lower compared with those obtained using the untreated material. A milder but still efficient method to reduce the bleeding level was found to be MAE with formic acid. In this case a bleeding level of 14 ng ml-1 was found after only a 1 h extraction time. In a second model system, using a polymer imprinted with L-phenylalanine anilide, the bleeding was reduced to a similar level by extensive on-line washing in good swelling solvents containing acid or base additives and after thermal annealing of the polymers in the dry state. 相似文献
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Multimode reader has been generally applied in immunoassay, and in the proposed paper, the 96 well micro-plate was modified with molecularly imprinted melamine sol-gel film, based on which the highly selective and high throughput detection of melamine was achieved. Melamine was imprinted into silica sol-gel films directly using phenyltrimethoxysilane and methyltrimethoxysilane as functionalized organosilicon precursors. The binding characteristic of the imprinted film to melamine was evaluated by equilibrium binding experiments and the morphology was studied by scanning electronic microscope (SEM). Scatchard analysis was carried out to estimate the binding parameters of the imprinted film. The proposed method exhibited excellent selectivity because of specific recognition of MM by molecularly imprinted film. Under the optimum conditions, the chemiluminescence (CL) intensity had a linear relationship against the concentration of melamine over the range of 0.1-50 μg mL−1 with a lower detection limit of 0.02 μg mL−1. 相似文献
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Kong LJ Pan MF Fang GZ Qian K Wang S 《Analytical and bioanalytical chemistry》2012,404(6-7):1653-1660
A simple electrochemical sensor based on a molecularly imprinted polymer film as the recognition element was developed for ractopamine (RAC) detection. This is the first report of a RAC-imprinted film on a gold electrode surface, synthesized through an electrochemical method using o-aminothiophenol as the functional monomer. The imprinting mechanism and experimental parameters affecting the capability of the imprinted film are discussed here. The sensor was successfully applied with constant potential amperometry for RAC detection in an indirect process with potassium ferricyanide as an electrochemical probe. The sensor had a rapid equilibrium time (120?s), high binding affinity and selectivity towards RAC, and with good reproducibility and stability. Under the experimental conditions applied, a linear relationship between the relative amperometric response and RAC ranged from 2.0?×?10(-7) to 1.4?×?10(-6)?mol?L(-1), with a lower limit of detection (LOD) of 2.38?×?10(-8)?mol?L(-1) (signal to noise ratio?=?3). The sensor was tested with feed samples spiked with trace amounts of RAC, with good recoveries between 87.4 and 90.5?%. 相似文献
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Selective removal of bisphenol A from wastewater is quite challenging primarily because of its low concentration and matrix complexity. To this end, according to the molecular structure of bisphenol A, we designed a functional monomer for the preparation of molecularly imprinted mesoporous silica using click chemistry reaction. The resultant bisphenol A imprinted mesoporous silica was characterized by transmission electron microscopy, small angle X‐ray diffraction, and N2 adsorption–desorption experiments. The results indicated that the bisphenol A imprinted mesoporous silica possessed a highly ordered periodic hexagonal mesostructure with the Brunauer–Emmett–Teller surface area of 944.28 m2/g. The bisphenol A imprinted mesoporous silica showed fast adsorption kinetics and the saturated adsorption capacity reached up to 88.6 mg/g at pH 6.5, and with relative selectivity factors ranged from 1.06 to 3.20. The adsorption efficiency of the bisphenol A imprinted mesoporous silica was above 97.96% after five extraction/elution cycles. The bisphenol A imprinted mesoporous silica was further applied to the selective removal of bisphenol A from real wastewater samples and showed great promise in practical applications. 相似文献
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Lee WC Cheng CH Pan HH Chung TH Hwang CC 《Analytical and bioanalytical chemistry》2008,390(4):1101-1109
Recent efforts in the investigation of chromatographic characterization of molecularly imprinted polymers (MIPs) have focused
mainly on the nature of heterogeneous binding sites. More data on the thermodynamics than on the kinetic features of MIP columns
have been published. The present article addresses the sources of peak broadening and tailing, which are the main drawbacks
often associated with imprinted polymers in chromatography for practical applications. With use of the theory of nonlinear
chromatography, the peak properties of a MIP column, including the retention and peak broadening and tailing, can be well
interpreted. Efforts to improve chromatographic efficiency using MIPs prepared by approaches different from the conventional
method, including covalent imprinting and the format of uniformly sized spherical microbeads, are reviewed and discussed.
This review leads to the conclusion that nonlinear chromatography theory is useful for characterizing chromatographic features
of MIP columns, since a MIP is essentially an affinity-based chromatographic stationary phase. We expect more theoretical
and experimental studies on the kinetic aspects of MIP columns, especially the factors influencing the apparent rate constant,
as well as the analysis of the influences of mobile-phase composition on the chromatographic performance. In addition to revealing
the affinity interaction by molecular recognition, slow nonspecific interactions which may be inherited from the imperfect
imprinting and may be involved in the rebinding of the template to MIPs also need to be characterized.
Figure The peak broadening and tailing associated often with molecularly imprinted polymers (MIPs) in column chromatography for practical
applications can be well characterized by the theory of nonlinear chromatography. 相似文献
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