分子印迹水相分离技术及其在分析化学中的应用

分子印迹分离技术通过模拟抗体-抗原相互作用原理,专一地与目标分子互补性结合,从而将目标分子与杂质分离,是一种非常具有发展前景的分离技术。传统的分子印迹技术通常是在有机相中制备对印迹分子具有选择性的印迹聚合物,然而分子印迹技术的实际应用环境大多是水相体系。近年来,分子印迹水相分离技术受到了科学工作者的广泛关注。本文分别从以下几个方面总结了分子印迹水相分离技术的最新研究进展:水相中分子印迹聚合物的设计原理与合成方法;印迹聚合物在水相中的作用机制;印迹水相分离技术在分析化学中的应用。最后讨论了该项技术现存的问题,并对其未来发展进行了展望。     

基于偶氮水杨醛酰腙的氰根比色检测探针的合成及性能

设计合成了一种基于酚羟基和氨基的酰腙类探针分子, 利用紫外-可见吸收光谱和核磁滴定考察了其对F^-, Cl^-, Br^-, I^-, CH₃COO^-, H₂PO₄^-, HSO₄^-, ClO₄^-, CN^-, SCN^-, SO^2-₄和NO^-₃等阴离子的识别作用. 结果表明, 当加入CN^-离子时主体溶液颜色由无色变为黄色, 而加入其它离子时主体溶液颜色不变, 说明该探针在DMSO/H₂O(体积比5: 5)体系中能选择性裸眼比色检测CN^-. 核磁滴定及质谱数据表明, 该探针与CN^-以1:1化学计量比结合, 该过程通过亲核加成方式完成.     

Construction of a novel electrochemical sensor based on molecularly imprinted polymers for the selective determination of chlorpyrifos in real samples

We present a novel electrochemical sensor based on an electrode modified with molecularly imprinted polymers for the detection of chlorpyrifos. The modified electrode was constructed by the synthesis of molecularly imprinted polymers by a precipitation method then coated on a glassy carbon electrode. The surface morphology of the modified electrode was characterized by using field‐emission scanning electron microscopy and transmission electron microscopy. The performance of the imprinted sensor was thoroughly investigated by using cyclic voltammetry and differential pulse voltammetry. The imprinted electrochemical sensor displayed high repeatability, stability, and selectivity towards the template molecules. Under the optimal experimental conditions, the peak current response of the imprinted electrochemical sensor was linearly related to the concentration of chlorpyrifos over the range 1 × 10⁻¹⁰–1 × 10⁻⁵ mol/L with a limit of detection of 4.08 × 10⁻⁹ mol/L (signal‐to‐noise ratio = 3). Furthermore, the proposed molecularly imprinted electrochemical sensor was applied to the determination of chlorpyrifos in the complicated matrixes of real samples with satisfactory results. Therefore, the molecularly imprinted polymers based electrochemical sensor might provide a highly selective, rapid, and cost‐effective method for chlorpyrifos determination and related analysis.     

分子印迹电位型传感器快速检测猪尿液中的克伦特罗

以盐酸克伦特罗为模板分子,采用沉淀聚合法合成了克伦特罗的分子印迹聚合物,并以其为离子载体,制得分子印迹聚合物膜克伦特罗离子选择性电极。在最优实验条件下,电极对克伦特罗阳离子的检出限可达7.0×10-8mol/L,线性范围为1.0×10-7～1.0×10-4mol/L,能斯特斜率为55.7 mV/decade。此电极具有优越的选择性、快速的响应时间以及良好的稳定性;已成功应用于实际猪尿样品中克伦特罗的测定,加标回收率为98%～107%,检测时间小于3 min。     

Design,Synthesis and Recognition Properties of a New Acetate Ion Receptor Based on Shiff-base Derivative

A simple colorimetric acetate ion receptor based on 3-methoxysalicylaldehyde-4'-nitrophenyl-hydrazone was synthesized in an ethanol solution through one step,and characterized by 1H NMR and elemental analyses.Its anion-binding ability was examined by UV-Vis absorption spectroscopy in DMSO(dimethyl sulfoxide).The result shows that the compound has a high affinity for and a high selectivity toward acetate ions,and also an advantage of 'naked-eye' recognition of color changing from yellow to purple.     

分子烙印聚合物的结构表征及手性拆分中的热力学研究

考察了一系列分子烙印聚合物的热稳定性和孔结构,探讨了孔结构与手性选择性的关系。计算了手性分离过程中的某些热力学参数的变化,发现分子烙印聚合物上的手性分离是一个焓控制的过程,热力学参数的变化同烙印分子的结构有关。     

基于硅材料的分子印迹聚合物的制备及应用*

分子印迹聚合物因制备简单、稳定性好、且具有分子识别功能使其在色谱分离、固相萃取、化学传感、模拟酶催化等方面有了广泛的应用。近年来,基于硅的分子印迹聚合物发展较为快速。本文主要介绍了以硅为母体材料和以硅为基质材料的分子印迹聚合物的制备及分子识别性质研究,并对其应用进行了分类,在此基础上对其将来的发展进行了展望。     

Tetracycline Potentiometric Sensor Based on Cyclodextrin for Pharmaceuticals and Waste Water Analysis

In this work, the construction and performance evaluation of PVC membranes ion‐selective electrodes for the determination of tetracycline type antibiotics is described. Electrodes with the best responses were based on plastic membranes containing 31% (w/w) PVC, 68% (w/w) of dibutylphthalate as plasticizer and 1% (w/w) of β‐cyclodextrin as ionophore. The electrodes were responsive over 6 months to tetracycline, oxytetracycline, doxycycline and chlortetracycline in glycine buffer solution (pH 2), in the dynamic range 2×10^?5–10^?2 mol L^?1 with a constant slope of about 55 mV/dec To enable large scale analysis reducing wastes as associated costs tubular shape electrodes were coupled to a sequential‐injection analysis system and its performance evaluated using pharmaceutical samples and waste waters from a treatment facility. The sample throughput of 51 samples h^?1 was enabled by the system as well as results that favorably agree with those provided by chromatographic analysis.     

Molecularly Imprinted Polymers (MIPs) in Sensors for Environmental and Biomedical Applications: A Review

Molecular imprinted polymers are custom made materials with specific recognition sites for a target molecule. Their specificity and the variety of materials and physical shapes in which they can be fabricated make them ideal components for sensing platforms. Despite their excellent properties, MIP-based sensors have rarely left the academic laboratory environment. This work presents a comprehensive review of recent reports in the environmental and biomedical fields, with a focus on electrochemical and optical signaling mechanisms. The discussion aims to identify knowledge gaps that hinder the translation of MIP-based technology from research laboratories to commercialization.     

石墨烯修饰电极分子印迹电化学传感器的研制及其对多巴胺的测定

以石墨烯为电极增敏材料,多巴胺印迹聚合物为特异性识别材料,采用滴涂法组装石墨烯修饰电极的分子印迹电化学传感器。考察了pH值、石墨烯浓度、印迹聚合物浓度对传感器的影响,优化的实验条件为:pH 7.0,石墨烯浓度为0.5g/L,印迹聚合物浓度为20g/L。实验表明,该印迹传感器对多巴胺的响应电流远大于非印迹电极,同时该印迹传感器对多巴胺具有较好的选择性,检测范围为2.0×10-7～1.0×10-4mol/L,检出限(S/N=3)为6.8×10-8mol/L。该传感器用于盐酸多巴胺注射液的测定,其回收率为98%～105%。     

基于表面分子印迹技术及相转化过程的双酚A电化学传感器

以双酚A (Bisphenol A, BPA)为模板, 氨基化硅胶为载体合成了对BPA有特异选择性的表面分子印迹聚合物(surface molecularly imprinted polymer, sMIP). 然后以聚氯乙烯(PVC)为支撑基质, 通过相转化过程(phase inversion process)制成BPA分子印迹聚合物膜, 将聚合物膜固载到处理过的金电极表面, 制成电流型双酚A电化学传感器. 优化了pH值、温度等实验条件, 结果表明在10～120 μg/mL范围内对双酚A有良好的线性响应(R＝0.9971). 传感器用于实际水样的测定, 结果令人满意.     

Computer‐aided design and synthesis of CdTe@SiO2 core–shell molecularly imprinted polymers as a fluorescent sensor for the selective determination of sulfamethoxazole in milk and lake water

In this work, a molecular dynamics simulation method was introduced to compute the preassembled system of molecular imprinted polymers for sulfamethoxazole monomer. The results revealed that the ratio of sulfamethoxazole as template molecule to 3‐aminopropyltriethoxysilane as functional monomer to tetraethylorthosilicate as cross‐linker of 10:10:40 led to the most stable template‐functional monomer cluster. Based on the result of computational simulation, CdTe@SiO₂ core–shell imprinted polymers, a cadmium telluride quantum dots layer on the surface of aminofunctionalized SiO₂, were synthesized as the fluorescent sensor. Then, a series of measures were used to characterize the structure and morphology to get optimal sensors. The concentration range was 5.0–30.0 μmol/L between molecular imprinted polymers at CdTe at SiO₂, and sulfamethoxazole of the fluorescence intensity. To further verify the reliability and accuracy of the fluorescent sensor, the application was successfully by analyzing sulfamethoxazole in pure milk and lake water. The results showed the recoveries were above 96.89% with a relative standard deviation of 1.25–5.45%, and the fluorescence sensor with selective recognition provides an alternative solution for the determination of sulfamethoxazole.     

Development of a Potentiometric Chemical Sensor for the Rapid Detection of Carbofuran Based on Air Stable Lipid Films with Incorporated Calix[4]arene Phosphoryl Receptor Using Graphene Electrodes

The present article describes a miniaturized potentiometric carbofuran chemical sensor on graphene nanosheets with incorporated lipid films. The graphene electrode was used for the development of a very selective and sensitive chemical sensor for the detection of carbofuran by immobilizing an artificial selective receptor on stabilized lipid films. The artificial receptor was synthesized by transformation of the hydroxyl groups of resorcin[4]arene receptor into phosphoryl groups. This chemical sensor responded for the wide range of carbofuran concentrations with fast response time of ca. 20 s. The presented potentiometric carbofuran chemical sensor is easy to construct and exhibits good reproducibility, reusability, selectivity, rapid response times, long shelf life and high sensitivity of ca. 59 mV/decade over the carbofuran logarithmic concentration range from 10^?6 to 10^?3 M.     

Reaction‐Based Colorimetric and Ratiometric Fluorescence Sensor for Detection of Cyanide in Aqueous Media

A stilbene‐based compound ( 1 ) has been prepared and was highly selective for the detection of cyanide anion in aqueous media even in the presence of other anions, such as F^?, Cl^?, Br^?, I^?, ClO₄^?, H₂PO₄^?, HSO₄^?, NO₃^?, and CH₃CO₂^?. A noticeable change in the color of the solution, along with a prominent fluorescence enhancement, was observed upon the addition of cyanide. The color change was observed upon the nucleophilic addition of the cyanide anion to the electron‐deficient cyanoacrylate group of 1 . The spectral changes induced by the reaction were analyzed by comparison with two model compounds, such as compound 2 with dimethyl substituents and compound 3 without a cyanoacrylate group. An intramolecular charge‐transfer (ICT) mechanism played a key role in the sensing properties, and the mechanism was supported by DFT/TDDFT calculations.     

Ion Interactions with a New Ditopic Naphthalimide‐Based Receptor: A Photophysical,NMR and Theoretical (DFT) Study

A new multi‐component chemosensor system comprising a naphthalimide moiety as fluorophore is designed and developed to investigate receptor–analyte binding interactions in the presence of metal and non‐metal ions. A dimethylamino moiety is utilized as receptor for metal ions and a thiourea receptor, having acidic protons, for binding anions. The system is characterized by conventional analytical methods. The absorption and fluorescence spectra of the system consist of a broad band typical for an intramolecular charge transfer (ICT). The effects of various metal‐ion additives on the spectral behavior of the present sensor system are examined in acetonitrile. It is found that among the metal ions studied, alkali/alkaline earth‐metal ions and transition‐metal ions modulate the absorption and fluorescence spectra of the system. As an additional feature, the anion signaling behavior of the system in acetonitrile is studied. A decrease in fluorescence efficiency of the system is observed upon addition of fluoride and acetate anions. Fluorescence quenching is most effective in the case of fluoride ions. This is attributed to the enhancement of the photoinduced electron transfer from the anion receptor to the fluorophore moiety. Hydrogen‐bond interactions between the acidic NH protons of the thiourea moiety and the F^? anions are primarily attributed to the fluoride‐selective signaling behavior. Interestingly, a negative cooperativity for the binding event is observed when the interactions of the system are studied in the presence of both Zn²⁺ and F^? ions. NMR spectroscopy and theoretical calculations are also carried out to better understand the receptor–analyte binding.     

磁性碳纳米管表面新型镉离子印迹聚合物制备及其对大米中的镉离子富集

以苯胺修饰的磁性碳纳米管为基质,Cd²⁺为模板,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,在碳纳米管表面制备出一种新型磁性Cd²⁺印迹聚合物(MWNTs/MIIPs)。 采用扫描电子显微镜和红外光谱等技术手段对其形态和化学结构等进行详细表征。 吸附试验结果表明,该磁性印迹材料对Cd²⁺离子具有良好的吸附能力,最大吸附量为16.96 mg/g;选择吸附试验结果表明,该磁性印迹材料对Cd²⁺/Cu²⁺、Cd²⁺/Ni²⁺、Cd²⁺/Pb²⁺和Cd²⁺/Cr³⁺的相对选择因子分别是2.03、2.35、2.16和2.13。 结合原子吸收光谱分析技术,该材料MWNTs/MIIPs可用于大米中的Cd²⁺快速分离富集检测。     

Synthesis and application of a peroxidase-like molecularly imprinted polymer based on hemin for selective determination of serotonin in blood serum

This work reports the preparation of a molecularly imprinted polymer (MIP) for selective catalytic detection of serotonin (5-hydroxytryptamine, 5-HT). The process is based on the synthesis of polymers with hemin introduced as the catalytic center to mimic the active site of peroxidase. The copolymer MIP, containing artificial recognition sites for 5-HT, has been prepared by bulk polymerization using methacrylic acid (MAA) and hemin as the functional monomers, and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. For the determination of 5-HT, a flow injection analysis system coupled to an amperometric detector was optimized using multivariate analysis. The effects of different parameters, such as pH, buffer flow rate, buffer nature, peroxide concentration and sample volume were evaluated. After optimizing the experimental conditions, a linear response range from 1.0 up to 1000.0 μmol L⁻¹ was obtained with a sensitivity of 0.4 nA/μmol L⁻¹. The detection limit was found to be 0.30 μmol L⁻¹, while the precision values (n = 6) evaluated by relative standard deviation (R.S.D.) were, respectively, 1.3 and 1.7% for solutions of 50 and 750 μmol L⁻¹ of 5-HT. No interference was observed by structurally similar compounds (including epinephrine, dopamine and norepinephrine), thus validating the good performance of the imprinted polymer. The method was applied for the determination of 5-HT in spiked blood serum samples.     

Reaction‐Based Ratiometric Chemosensor for Instant Detection of Cyanide in Water with High Selectivity and Sensitivity

A highly selective chemosensor 1 based on an acylhydrazone group as binding site and naphthalene group as the fluorescence signal group were described, which could instantly detect CN^? in water with specific selectivity and high sensitivity. The detection of cyanide was performed via the nucleophilic attack of cyanide anion on the carbonyl group, which could be confirmed by ¹H NMR, ¹³C NMR, ESI‐MS and DFT calculations. The addition of CN^? to sensor 1 induced a remarkable color change from colorless to yellow and generated a blue fluorescence, these sense procedure could not interfered by other coexistent competitive anions (F^?, Cl^?, Br^?, I^?, AcO^?, H₂PO₄^?, HSO₄^?, ClO₄^?, SCN^?, S^2?, NO₃^? and SO₄^2?). The detection limits were 5.0×10^?7 M and 2.0×10^?9 M of CN^? using the visual fluorescent color changes and fluorescence spectra changes respectively, which is far lower than the WHO guideline of 1.9×10^?6 M . Test strips based on sensor 1 were fabricated, which could act as a convenient and efficient CN^? test kit to detect CN^? in pure water for “in‐the‐field” measurement.