Flow chemiluminescence sensor for determination of clenbuterol based on molecularly imprinted polymer

In this paper, a novel flow chemiluminescence (CL) clenbuterol sensor based on molecularly imprinted polymer (MIP) on line enrichment nanogram clenbuterol and chemiluminescence reaction of potassium permanganate and formaldehyde in the polyphosphate enhanced by clenbuterol. Clenbuterol in the urine was selectively adsorbed on the clenbuterol-imprinted polymer, which was packed into the flow cell. The formaldehyde and the polyphosphate with potassium permanganate flowed through the flow cell and reacted with the on line adsorbed clenbuterol and produced strong CL. The results show that the sensor was reversible. The CL intensity was linear with clenbuterol concentration from 1.0 × 10⁻⁹ g/mL to 5.0 × 10⁻⁸ g/mL. The detection limit was 3.0 × 10⁻¹⁰ g/mL. The R.S.D. for ng/mL clenbuterol was less than 5% (n = 3). The present method offered a high selectivity and sensitivity that made the quantitative analysis of trace clenbuterol (ng/mL) in the animal urine sample.     

A molecularly imprinted photonic polymer sensor with high selectivity for tetracyclines analysis in food

A molecularly imprinted photonic polymer (MIPP) sensor for respective detection of tetracycline, oxytetracycline and chlortetracycline is developed based on the combination of a colloidal crystal templating method and a molecular imprinting technique. Colloidal crystal templates are prepared from monodisperse polystyrene colloids. The molecularly imprinted polymer, which is embodied in the colloidal crystal templates, is synthesized with acrylic acid and acrylamide as monomers, N,N'-methylene bisacrylamide as a cross-linker and tetracyclines (TCs) as imprinting template molecules. After removal of the colloidal crystal template and the molecularly imprinted template, the resulted MIPP consists of a three-dimensional, highly ordered and interconnected macroporous array with a thin hydrogel wall, where nanocavities complementary to analytes in shape and binding sites are distributed. The response of MIPP to TCs stimulants in aqueous solution is detected through a readable Bragg diffraction red-shift, which is due to the lattice change of MIPP structures responding to their rebinding to the target TCs molecules. A linear relationship was found between the Δλ and the concentration of TCs in the range from 0.04 μM to 0.24 μM. With this sensory system, direct and selective detection of TCs has been achieved without using label techniques and expensive instruments. The developed method has been applied successfully to detect tetracycline in milk and honey samples.     

基于分子印迹聚合物的化学发光传感器测定尿样中的甲福明

合成了甲福明的分子印迹聚合物,以此聚合物为识别物质,在线分离富集甲福明,建立了一种测定甲福明的流动式化学发光但感器。N-溴代丁二酰亚胺(NBS)和荧光素与甲福明发生化学反应,产生强的化学发光。甲福明质量浓度在2×10-8~8×10-6g/mL范围内同发光强度成良好线性关系,方法的检出限为6×10-9g/mL,相对标准偏差小于5%(n=9)。选择性实验表明将分子印迹聚合物作为识别物质应用于化学发光分析中,能大大提高化学发光分析方法的选择性。该传感器可逆性强、稳定性好,可重复使用100次以上,已用于人体尿样中甲福明的测定。     

Capacitive chemical sensor for fenvalerate assay based on electropolymerized molecularly imprinted polymer as the sensitive layer

A capacitive chemical sensor for fenvalerate is reported. By using ac impedance measurements the sensor has been based on the decrease in capacitance caused by the analyte used as the template in the formulation of an electropolymerized molecularly imprinted polymer as receptor layer. Improvement of the insulating properties of the sensor was investigated in detail. The capacitive sensor was prepared by a deposition of a self-assembled monolayer of 2-mercaptobenzimidazole (2-MBI) before electropolymerization of 2-MBI and subsequent treatment with n-dodecanethiol to eliminate pinholes and defects in the polymerized 2-MBI film. From the calibration curve concentrations of fenvalerate up to 9 g mL^–1 could be detected with a linear determination range up to 5 g mL^–1 and a detection limit of 0.36 g mL^–1. No significant interference was observed from common pyrethroid insecticides.     

A novel molecularly imprinted electrochemiluminescence sensor for isoniazid detection

Based on Ru(bpy)(3)(2+)-Au nanoparticles decorated multi-walled carbon nanotubes composites and a molecularly imprinted polymer (MIP), we propose a novel molecularly imprinted electrochemiluminescence (ECL) sensor to selectively determine isoniazid (INH). The MIP is synthesized through electrochemical copolymerization of acrylamide and N,N'-methylene diacrylamide in the presence of INH template molecules. The enhanced ECL intensity is linear in the range of 0.1 to 110 μg cm(-3) and the detection limit is 0.08 μg cm(-3) (3σ) INH with relative standard deviation 3.8% (n = 6) for 8 μg cm(-3). As a result, the sensor has been successfully applied to the determination of INH in human urine and pharmaceutical samples. Moreover, the possible ECL mechanism is discussed.     

A novel electrochemical sensor based on molecularly imprinted polymers for caffeine recognition and detection

A sensitive and selective electrochemical sensor based on molecularly imprinted polymers (MIPs) was developed for caffeine (CAF) recognition and detection. The sensor was constructed through the following steps: multiwalled carbon nanotubes and gold nanoparticles were first modified onto the glassy carbon electrode surface by potentiostatic deposition method successively. Subsequently, o-aminothiophenol (ATP) was assembled on the surface of the above electrode through Au–S bond before electropolymerization. During the assembled and electropolymerization processes, CAF was embedded into the poly(o-aminothiophenol) film through hydrogen bonding interaction between CAF and ATP, forming an MIP electrochemical sensor. The morphologies and properties of the sensor were characterized by scanning electron microscopy, cyclic voltammetry, and differential pulse voltammetry. The recognition and determination of the sensor were observed by measuring the changes of amperometric response of the oxidation-reduction probe, [Fe(CN)₆]^3?/[Fe(CN)₆]^4?, on modified electrode. The results demonstrated that the prepared sensor had excellent selectivity and high sensitivity for CAF, and the linear range was 5.0?×?10^?10?~?1.6?×?10^?7?mol?L^?1 with a detection limit of 9.0?×?10^?11?mol?L^?1 (S/N?=?3). The sensor was also successfully employed to detect CAF in tea samples.     

Flow-injection chemiluminescence sensor for determination of isoniazid in urine sample based on molecularly imprinted polymer

In this paper, molecularly imprinted polymer (MIP) of isoniazid is synthesized through thermal radical copolymerization of metharylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of isoniazid template molecules. A novel flow injection chemiluminescence sensor for isoniazid determination is developed by packing the isoniazid-MIP into the flow cell as recognition elements. Isoniazid could be selectively adsorbed by the MIPs and the adsorbed isoniazid was sensed by its great enhancing effect on the weak CL reaction between luminol and periodate which were mixed in the flow cell. The enhanced CL intensity is linear in the range 2x10(-9) to 2x10(-7) g/mL and the detection limit is 7x10(-10) g/mL (3sigma) isoniazid with a relative standard deviation 2.8% (n=9) for 8x10(-8) g/mL. The sensor is reversible and reusable. It has a great improvement in sensitivity and selectivity for CL analysis. As a result, the sensor has been successfully applied to determination of isoniazid in human urine. At the same time, the binding characteristic of the polymer to isoniazid was evaluated by batch method and the dynamic method, respectively.     

A novel high selective and sensitive metronidazole voltammetric sensor based on a molecularly imprinted polymer-carbon paste electrode

The design and construction of a highly selective voltammetric sensor for metronidazole by using a molecularly imprinted polymer (MIP) as recognition element were introduced. A metronidazole selective MIP and a nonimprinted polymer (NIP) were synthesized and then incorporated in the carbon paste electrodes (CPEs). The sensor was applied for metronidazole determination using cathodic stripping voltammetric method. The MIP-CP electrode showed very high recognition ability in comparison to NIP-CPE. Some parameters affecting the sensor response were optimized and then the calibration curve was plotted. Two dynamic linear ranges of 5.64 × 10⁻⁵ to 2.63 × 10⁻³ mg L⁻¹ and 2.63 × 10⁻³ to 7.69 × 10⁻² mg L⁻¹ were obtained. The detection limit of the sensor was calculated as 3.59 × 10⁻⁵ mg L⁻¹. This sensor was used successfully for metronidazole determination in biological fluids.     

分子印迹化学发光传感器在线检测牛肉与鸡肉组织中残留的磺胺嘧啶

以分子印迹作为识别体,制成高灵敏度和高选择性的化学发光传感器在线检测牛肉与鸡肉组织中残留的磺胺嘧啶。磺胺嘧啶作为靶分子,通过悬浮聚合制备了1～10μm的分子印迹聚合物。将分子印迹聚合物装入聚四氟乙烯管中,作为固相萃取柱,并联在八通阀上,用于在线选择吸附磺胺嘧啶。在最佳条件下,测得磺胺嘧啶线性范围7.0×10–9～9.0×10–7g/mL,方法的检出限为(3σ)2×10–10g/mL,11次平行测定3.0×10–8g/mL的磺胺嘧啶溶液的化学发光强度相对标准偏差为3.4%。方法能够用于检测肉类产品中残留的磺胺嘧啶。     

A novel high selective and sensitive para-nitrophenol voltammetric sensor, based on a molecularly imprinted polymer-carbon paste electrode

By using a molecularly imprinted polymer (MIP) as a recognition element, the design and construction of a high selective voltammetric sensor for para-nitrophenol was formed. Para-nitrophenol selective MIP and a non-imprinted polymer (NIP) were synthesized, and then used for carbon paste (CP) electrode preparation. The MIP-CP electrode showed greater recognition ability in comparison to the NIP-CP. It was shown that electrode washing after para-nitrophenol extraction led to enhanced selectivity, without noticeably decreasing the sensitivity. Some parameters affecting sensor response were optimized and a calibration curve was plotted. A dynamic linear range of 8 × 10⁻⁹ to 5 × 10⁻⁶ mol L⁻¹ was obtained. The detection limit of the sensor was calculated as 3 × 10⁻⁹ mol L⁻¹. Thus, this sensor was used successfully for the para-nitrophenol determination in different water samples.     

A novel method to prepare SPR sensor chips based on photografting molecularly imprinted polymer

A novel method to prepare surface plasmon resonance(SPR) sensor chips based on grafted imprinted polymer is explored. Benzophenone photografting system is used to grow molecularly imprinted polymer(MIP) films from the modified surface of gold substrate.The surface morphology and thickness of MIP films were investigated by scanning electronic microscope(SEM).The adsorption properties of sensor chip were studied by SPR spectroscopy.The results demonstrate that nano-MIP films can be constructed on the surface of gold substrate with the good adsorption of template molecules.     

Dopamine sensor based on molecularly imprinted electrosynthesized polymers

Molecularly imprinted polymers (MIPs) have been applied as molecular recognition elements to chemical sensors. In this paper, we combined the use of MIPs and electropolymerization to produce a sensor which was capable of detecting dopamine (DA). The MIP electrode was obtained by electrocopolymerization of o-phenylenediamine and resorcinol in the presence of the template molecular DA. The MIP electrode exhibited a much higher current response compared with the non-imprinted electrode. The response of the imprinted sensor to DA was linearly proportional to its concentration over the range 5.0 × 10⁻⁷-4.0 × 10⁻⁵ M. The detection limit of DA is 0.13 μM (S/N = 3). Moreover, the proposed method could discriminate between DA and its analogs, such as ascorbic acid and uric acid. This method was successfully applied to the determination of DA in dopamine hydrochloride injection and healthy human blood serum. These results revealed that such a sensor fulfilled the selectivity, sensitivity, sped, and simplicity requirements for DA detection and provided possibilities of clinical application in physiological fields.     

Potentiometric propranolol-selective sensor based on molecularly imprinted polymer

A novel potentiometric sensor based on molecularly imprinted polymer (MIP) for propranolol, an adrenergic-blocking drug, was designed. The influence of molecularly imprinted polymer particle content and sodium tetraphenylborate additives in polyvinylchloride membrane was shown. The electrodes show near-Nernstian responses down to 10^?4–10^?5?M propranolol concentration. The potentiometric response of MIP-based sensor for propranolol in mixed nonaqueous medium was shown at first. Sensor selectivity relative to various inorganic cations, atenolol and metoprolol, was reported. Direct potentiometry was used to determine propranolol in aqueous modeling solutions and pharmaceutical preparations with good results.     

A sensitive nicotine sensor based on molecularly imprinted electropolymer of o-aminophenol

A sensitive nicotine sensor based on a molecularly imprinted electropolymer of o-aminophenol is proposed and its configuration and performance are studied in detail. On the condition of weak acidity, the sensitive layer was prepared by electropolymerization of o-aminophenol on a gold electrode in the presence of the template (nicotine). The sensor exhibits good selectivity and sensitivity to nicotine. The determination limit is 2.0×10⁻⁷ mol/L and a linear relationship between the current and concentration is found in the range of 4.0×10⁻⁷ ∼ 3.3 ×10⁻⁵ mol/L. The sensor has also been applied to the analysis of nicotine in tobacco samples with recovery rates ranging from 99.0% to 102%. __________ Translated from Journal of Hunan university (Nature Science), 2005, 32(3) (in Chinese)     

Quantification of fenfluramine with a molecularly imprinted chemiluminescence sensor and sulfonophenylazo rhodanine

Fenfluramine-imprinted polymer was prepared by self assembly with acrylic amide as functional monomer and ethylene glycol dimethacrylate as crosslinker. The binding characteristics of the imprinted polymer to fenfluramine were evaluated by equilibrium binding experiments and the morphology was studied by SEM. Taking the imprinted polymer as recognition material, using the new 3-p-nitrylphenyl-5-(4′-methyl-2′-sulfonophenylazo)rhodanine (M4NRASP) synthesized by the authors as chemiluminescence reagent, a new highly selective flow injection chemiluminescence sensor for trace fenfluramine with good sensitivity was established which utilized the chemiluminescence reaction between fenfluramine, M4NRASP, and potassium permanganate in hydrochloric acid. The traditional flow-through cell was replaced with a polymethyl methacrylate module, with Y-shaped flow path, through which the above three reactants were injected simultaneously. Under optimum conditions the relative chemiluminescence intensity shows a linear relationship with the concentration of fenfluramine over the range of 5×10^–7 to 8×10^–6 g/mL with a lower detection limit of 3.4×10^–8 g/mL. The relative standard deviation for the determination of 1.0×10^–6 g/mL fenfluramine solution was 2.4% (n = 11). This proposed sensor could be satisfactorily applied to the determination of fenfluramine in weight-reducing capsules.     

A molecularly imprinted electrochemical sensor based on Au nanocross-chitosan composites for detection of paraquat

Journal of Solid State Electrochemistry - A novel electrochemical sensor for paraquat (PQ) detection based on molecularly imprinted polymer (MIP) membranes on a glassy carbon electrode (GCE)...     

氯丙嗪分子印迹化学发光微流控传感器芯片的研究

以氯丙嗪分子印迹聚合物为识别物质,以鲁米诺-K3Fe(CN)6化学发光体系,建立了一种新型的氯丙嗪化学发光微流控分子印迹传感器芯片的检测方法。利用二氧化碳激光在聚甲基丙烯酸甲酯材质上刻蚀出200μm宽,150μm深的微通道,8 mm长,1 mm宽,0.5 mm深的微检测池。微检测池中填充50μm粒径大小的热聚合得到的氯丙嗪分子印迹聚合物作为识别物质,在线富集氯丙嗪,富集的氯丙嗪可以增强鲁米诺和K3Fe(CN)6的化学发光强度,以化学发光强度定量氯丙嗪量。该传感器的响应值与0.02~0.4μg/mL氯丙嗪呈良好的线性关系,检出限为8 ng/mL(3σ)。该微流控传感器芯片已用于测定人尿液中的氯丙嗪。     

Bulk acoustic wave sensor for herbicide assay based on molecularly imprinted polymer

A novel molecularly imprinted polymer (MIP) coated bulk acoustic wave (BAW) sensor was fabricated for liquid phases. It can be used as a sensitive portable implement for the assay of 2,4-dichlorophenoxyacetic acid. A logarithmic response relationship between 2.0 × 10^–7 M and 5.0 × 10^–4 M was found. The detection limit was 1.0 × 10^–7 M. Recoveries were 93.2–108.7%. Influencing factors were investigated in detail and optimized.     

Bulk acoustic wave sensor for herbicide assay based on molecularly imprinted polymer

A novel molecularly imprinted polymer (MIP) coated bulk acoustic wave (BAW) sensor was fabricated for liquid phases. It can be used as a sensitive portable implement for the assay of 2,4-dichlorophenoxyacetic acid. A logarithmic response relationship between 2.0 x 10(-7) M and 5.0 x 10(-4)M was found. The detection limit was 1.0 x 10(-7) M. Recoveries were 93.2-108.7%. Influencing factors were investigated in detail and optimized.     

Biomimetic piezoelectric quartz sensor for caffeine based on a molecularly imprinted polymer

A piezoelectric quartz sensor coated with molecularly imprinted polymer (MIP) for caffeine was developed. The MIP was prepared by co-polymerizing methacrylic acid (MAA) and ethylene glycol dimethacrylate (EDMA) in the presence of azobis(isobutyronitrile) as initiator, caffeine as template molecule, and chloroform as solvent. The MIP suspension in polyvinyl chloride/tetrahydrofuran (6:2:1 w/w/v) solution was spin coated onto the surface of the electrode of a 10 MHz AT-cut quartz crystal. The sensor exhibited a linear relationship between the frequency shift and caffeine concentration in the range of 1×10^–7 mg mL^–1 up to 1x10^–3 mg mL^–1 [correlation coefficient (r)=0.9935] in a stopped flow measurement mode. It has a sensitivity of about 24 Hz/ln(concentration, mg mL^–1). A steady-state response was achieved in less than 10 min. The performance characteristic of the sensor shows a promising and inexpensive alternative method of detecting caffeine. Surface studies were carried out for the reagent phase of the sensor using SEM, AFM, and XPS analysis in order to elucidate the imprinting of the caffeine molecule. The SEM micrograph, AFM image, and XPS spectra confirmed the removal of caffeine by Soxhlet extraction in the imprinting process and the rebinding of caffeine to the MIP sensing layer during measurement.