Development of a Creatinine Sensor Based on a Molecularly Imprinted Polymer‐Modified Sol‐Gel Film on Graphite Electrode

An electrochemical creatinine sensor based on a molecularly imprinted polymer (MIP)‐modified sol‐gel film on graphite electrode was developed. The surface coating of MIP over sol‐gel was advantageous to obtain a porous film with outwardly exposed MIP cavities for unhindered selective rebinding of creatinine from aqueous and biological samples. A fast differential pulse, cathodic stripping voltammetric response of creatinine can be obtained after being preanodized the sensor in neutral medium containing appropriate amount of creatinine at +1.8 V versus SCE for 120 s. A linear response over creatinine concentration in the range of 1.23 to 100 μg mL^?1 was exhibited with a detection limit of 0.37 μg mL^?1 (S/N=3).     

碳纳米管修饰电极分子印迹传感器快速测定沙丁胺醇

以单壁碳纳米管(SWNTs)为电极材料,应用分子印迹技术,以邻苯二胺为功能单体、沙丁胺醇为模板,采用电化学聚合法制备了一种新型的快速检测沙丁胺醇分子印迹传感器,并运用电化学方法去除模板.在磷酸盐缓冲溶液(PBS)中,利用线性溶出伏安法对印迹和非印迹膜的性能进行了比较,对分子印迹膜的影响因素进行了优化.实验表明,本传感器...     

Electrosynthesis of Molecularly Imprinted Poly‐o‐phenylenediamine on MWCNT Modified Electrode for Selective Determination of Meldonium

In this study, a molecularly imprinted polymer (MIP) was synthesized by electrochemical polymerization and used to construct an electrochemical sensor for determination of meldonium (MEL) selectively for the first time. The polymer film was generated by using o‐phenylenediamine (o‐PD) as a monomer on the surface of carboxylic acid functionalized multiwalled carbon nanotube (MWCNT) modified pencil rod electrode in the presence of MEL as a template. MEL imprinted (MEL‐imp) and non‐imprinted (N‐imp) polymer films and coated electrodes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), profilometry, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Voltammetric measurements were carried out in a ferrocyanide/ferricyanide redox probe solution for MEL‐imp and N‐imp electrodes in the presence and absence of template molecule. The decrease in peak current of redox probe was linear with the concentration of MEL in the range of 0.1–5 μg/mL and the limit of detection (3 s/b) was found to be 0.066 μg/mL under optimized experimental conditions. The proposed sensor was successfully applied for selective determination of MEL in human urine sample with long term stability and good reproducibility.     

Electrochemical Sensor for trans‐Resveratrol Determination Based on Indium Tin Oxide Electrode Modified with Molecularly Imprinted Self‐Assembled Films

A voltammetric sensor for sensitive and specific determination of trans‐resveratrol (RES) were prepared based on immobilization of an RES‐imprinted film on the surface of functionalized Indium Tin Oxide (ITO) electrode, which was modified with γ‐methacyloxypropyl trimethoxysilane (γ‐MPS). Cyclic Voltammetry (CV) was presented to extract RES from the molecularly imprinted polymer film and RES were extracted rapidly and completely. The binding performance of the imprinted electrode with the template RES were investigated using differential pulse voltammetry (DPV). The results showed that the imprinted ITO film can give selective recognition to the template RES over that of structurally analogous molecules. A linear response to RES in the concentration range of 2.0×10^?6 M to 2.0×10^?5 M was observed with a correlation coefficient of 0.992, and the detection limit of the electrochemical sensor was 8.0×10^?7 M. Whereas, binding to the reference nonimprinted electrode, made in the same way but without the addition of template RES, there was almost no response to RES.     

基于石墨烯分子印迹电化学传感器测定芦丁

将石墨烯(GR)滴涂至裸Au电极表面,并以邻氨基酚为功能单体,芦丁为模板分子,制备了芦丁分子印迹膜电化学传感器,利用循环伏安法(CV)和差分脉冲伏安法(DPV)对制得的传感器进行了电化学性能研究,并且对制备条件和测定条件进行了优化。结果表明,与裸Au电极相比,该GR修饰的Au电极在[Fe(CN)_6]~(3-/4-)溶液中峰电流明显增大,显著提高了芦丁分子印迹传感器的灵敏度。在最优实验条件下,基于GR分子印迹电化学传感器在4.40×10~(-6)~2.80×10~(-4) mol/L范围内呈良好的线性关系,检测限为1.46×10~(-6) mol/L。用该传感器测定了黑茶中芦丁的含量,获得较好结果。     

Au-Pd合金纳米管修饰的尼古丁分子印迹膜传感器的研究

基于Au-Pd合金修饰的玻碳电极为工作电极,采用循环伏安法将邻氨基酚与尼古丁电沉积在工作电极上,制备了尼古丁分子印迹膜传感器。采用差分脉冲伏安法研究尼古丁在尼古丁分子印迹膜传感器上的电化学行为,考察了模板溶解时间、富集时间和溶液pH值对尼古丁测定的影响。在优化实验条件下,尼古丁分子印迹膜传感器的线性范围为1.2×10~(-7)~2.5×10~(-3) mol/L,检出限为4.6×10~(-8) mol/L。用该传感器对吸烟者血液中尼古丁的含量进行检测,结果表明,该传感器具有灵敏度高、线性范围宽、重现性及稳定性好等优点。     

Electrochemical Detection of 2‐Naphthol at a Glassy Carbon Electrode Modified with Tosflex Film

In this study, a Tosflex (a perfluoro‐anion‐exchange membrane) modified glassy carbon electrode has been used to detect 2‐naphthalenol (2‐naphthol) in aqueous solutions in order to demonstrate the electroanalytical application of Tosflex. 2‐naphthol polymerizes upon electrochemical oxidation at a glassy carbon electrode; however, the current related to this oxidation is too small for analytical purpose at low concentration level. A Tosflex polymer modified glassy carbon electrode (TFGCE) was found of having capability to improve the detection limit because 2‐naphthol molecules deprotonated in basic solutions to form 2‐naphtholate anions that were accumulated to TFGCE by the anion‐exchange characteristic of Tosflex. The accumulated 2‐naphtholate anions were determined with the following differential pulse voltammetry. With 3 minutes accumulation at +0.05 V, the dependence of oxidation current versus concentration was linear from 8×10^?7 M to 1×10^?5 M with a regression coefficient of 0.999 and a detection limit of 2×10^?7 M. Unlike many other anion‐exchange polymer modified electrodes, the TFGCE is stable at highly basic condition.     

Development of Uric Acid Sensor Based on Molecularly Imprinted Polymer‐Modified Hanging Mercury Drop Electrode

Uric acid (UA) sensor based on molecularly imprinted polymer‐modified hanging mercury drop electrode was developed for sensitive and selective analysis in aqueous and blood serum samples. The uric acid‐imprinted polymer was prepared from melamine and chloranil and coated directly onto the surface of a hanging mercury drop electrode, under charge‐transfer interactions at +0.4 V (vs. Ag/AgCl), in model 303A electrode system connected with a polarographic analyzer/stripping voltammeter (PAR model 264A). The binding event of uric acid was detected in the imprinted polymer layer through differential pulse, cathodic stripping voltammetry (DPCSV) at optimized operational conditions [accumulation potential +0.4 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.0, scan rate 10 mV s^?1, pulse amplitude 25 mV]. The limit of detection for UA was found to be 0.024 μg mL^?1 (RSD=0.64%, S/N=3). Under the optimized operational conditions, the sensor was able to differentiate between uric acid and other closely structural‐related compounds and interfering substances. Ascorbic acid (AA), a major interferent in UA estimation, was not adsorbed on the surface of sensor electrode. The present sensor is, therefore, UA‐selective at all concentrations of AA present in human blood serum samples. The précised and accurate quantification of UA have been made in the dilute as well as concentrated regions varying within limits 0.1–4.0 and 9.8–137.0 μg mL^?1, respectively.     

High‐Selective Tramadol Sensor Based on Modified Molecularly Imprinted Polymer?Carbon Paste Electrode with Multiwalled Carbon Nanotubes

We report here a novel carbon paste electrode (CPE) which is able to quantitatively sense tramadol under physiological conditions without sample preparation step. The selectivity of CPE is modified by applying molecularly imprinted polymer (MIP) technology. Multiwalled carbon nanotubes (MWCNTs) are incorporated in the structure of CPE to improve the conductivity and the ion‐to‐electron transduction. The electrode shows a wide dynamic linear range for tramadol from 10^?7 to 10^?3 M. The observed limit of detection and % RSD are 5×10^?7 M and 1.8 %, respectively. Finally, the proposed method is applied to determine tramadol in urine and medicinal tablets.     

Determination of Tetracycline at a UV‐Irradiated DNA Film Modified Glassy Carbon Electrode

In this study, interaction of tetracycline (TC) and DNA in the Britton? Robinson buffer solution (BR) was studied by cyclic voltammetry. The experimental results reveal that TC can bind strongly to DNA and the association constant and binding number between TC and DNA was obtained. Then DNA was immobilized on a glassy carbon electrode by UV‐irradiation. Through this process, water‐soluble DNA was converted into insoluble materials, and a stable DNA film was formed on the electrode. The electrochemical oxidation behavior of TC was studied at UV‐irradiated DNA film modified glassy carbon electrode (UV‐DNA‐GCE). The response of modified electrode was optimized with respect to pH, accumulation time, ionic strength, drug concentration and other variables. TC at the surface of modified electrode showed a linear dynamic range of 0.30–90.00 µM and a detection limit of 0.27 µM. To demonstrate the applicability of the modified electrode, it was used for the analysis of real samples such as pharmaceutical formulations and milk.     

多壁碳纳米管修饰电极分子印迹传感器测定咖啡因

以咖啡因为模板分子,通过电聚合邻苯二胺,在羧基化多壁碳纳米管修饰的玻碳电极表面制备了对咖啡因有特异响应的分子印迹聚合物膜。通过循环伏安法和线性扫描伏安法对传感器的性能进行表征,并优化了检测条件,研究了印迹传感器对模板分子咖啡因及其结构类似物的选择性响应。在最优实验条件下,电化学探针K3[Fe(CN)6]的峰电流与咖啡因浓度在2.0×10-7~2.0×10-5mol·L-1范围内呈良好的线性关系,检出限为4.0×10-8mol·L-1。该传感器应用于铁观音茶叶中咖啡因含量的测定,其回收率为94%~106%。     

A High Sensitivity Electrochemical Sensor Based on Fe3+‐Ion Molecularly Imprinted Film for the Detection of T‐2 Toxin

The excellent detection sensitivity in various matrices of T‐2 toxin (T‐2), which has cytotoxic and immunosuppressive effects in DNA and RNA synthesis, is a highly desirable characteristic. A sensitive molecularly imprinted electrochemical sensor was constructed for the selective detection of T‐2. In this study, iron ions (Fe³⁺) were introduced to increase the chelation of the metal ions and templates for preparing molecularly imprinted polymers (MIPs). With the increased chelation of the metal ions and templates, the selectivity and sensitivity of the MIPs were effectively improved. The imprinted sensor was successfully employed to detect T‐2 in cereals and human serum samples.     

基于石墨烯的毒死蜱分子印迹电化学传感器的制备及对毒死蜱的测定

利用分子印迹技术,以马来松香丙烯酸乙二醇酯为交联剂,使用自由基热聚合法在石墨烯修饰的玻碳电极表面合成毒死蜱( CPF)分子印迹聚合膜,制得了CPF分子印迹电化学传感器。采用循环伏安法、线性扫描伏安法和电化学交流阻抗法等,考察了此CPF分子印迹膜的电化学性能。在最佳检测条件下,传感器的峰电流与CPF浓度在2.0×10-7~1.0×10-5mol/L范围内呈线性关系,线性方程为Ip(μA)=-7.1834-0.2424C (μmol/L),相关系数r2=0.9959,检出限为6.7×10-8 mol/L(S/N=3)。构建了CPF分子印迹电化学传感器的动力学吸附模型,测得印迹传感器的印迹因子β=2.59,结合速率常数k=12.2324 s。传感器表现出良好的重现性和稳定性,并成功用于实际水样和蔬菜样品中CPF的测定,加标回收率为94.1%~101.4%。     

吲哚-3-乙酸分子印迹聚合物膜电化学传感器的研制

利用分子印迹技术,以吲哚-3-乙酸(IAA)为模板分子,甲基丙烯酸为单体,在玻碳电极表面采用原位聚合制备分子印迹敏感膜.采用方波伏安法对吲哚乙酸在该印迹电极上的电化学行为进行了研究.结果表明,0.62 V(vs.SCE)处的峰电流与吲哚乙酸的浓度在5.0×10-6～2.0×10-4mol/L范围内呈线性关系,检出限(S...     

Morphine Sensing by a Green Modified Molecularly Imprinted Poly L‐Lysine/Sodium Alginate‐activated Carbon/Glassy Carbon Electrode Based on Computational Design

A different molecularly imprinted composite film with the exploit of computational design is synthesized. The proposed composite is used for electrode modification to determine morphine. The ratio of monomer to template in optimum condition was obtained 4. The modification of the electrode was achieved by electropolymerizing L‐lysine in the presence of morphine on the surface of sodium alginate and activated carbon (SA‐AC) on glassy carbon electrode (GCE). The SA‐AC composite with special surface area suits for making sensitive sensors. Morphine showed an anodic peak in buffer solution of phosphate (pH=6.0) on MIP/SA‐AC/GCE. The optimization of the practical factors on the response and electrochemical behavior of template morphine on the modified electrode were precisely surveyed. The DPV outcomes exhibit high sensitivity for morphine detection within 0.1–1000.0 μM and limit of detection as 48 nM (S/N=3). The application of this disposable sensor in the case of urine samples was quite satisfactory.     

Capacitive Chemical Sensor for Thiopental Assay Based on Electropolymerized Molecularly Imprinted Polymer

A novel capacitive sensor based on electropolymerized molecularly imprinted polymer (MIP) for thiopental detection is described. The molecularly imprinted film as a recognition element was prepared by electropolymerization of phenol on a gold electrode in the presence of thiopental (template). Cyclic voltammetry and capacitive measurements were used for characterization and evaluation of the polymeric film. The template molecules were removed from the modified electrode surface by washing with an ethanol:water solution. The sensor’s linear response range was between 3 and 20 µM, with a detection limit of 0.6 µM. The proposed sensor exhibited good selectivity, reproducibility. Satisfactory results were obtained in the direct detection of real samples.     

A Polypyrrole‐Imprinted Electrochemical Sensor Based on Nano‐SnO2/Multiwalled Carbon Nanotubes Film Modified Carbon Electrode for the Determination of Oleanolic Acid

A sensitive molecularly imprinted electrochemical sensor with specific recognition ability for oleanolic acid was synthesized by modification of multiwalled carbon nanotubes (MWNTs) decorated with tin oxide nanoparticles (nano‐SnO₂/MWNTs) and polypyrrole‐imprinted polymer on a carbon electrode. The morphology and electrochemical performance of the imprinted sensor were investigated by using scanning electron microscope (SEM), X‐ray diffraction (XRD), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometric i–t curve. The results showed that the imprinted sensor displayed excellent selectivity toward oleanolic acid. A linear relationship between the response currents and oleanolic acid concentrations ranging from 5.0×10^?8 g/L to 2.0×10^?5 g/L was obtained for the imprinted sensor. The limit of detection (LOD) of the imprinted sensor toward oleanolic acid was calculated as 8.6×10^?9 g/L at a signal to noise ratio (S/N) of 3. This imprinted sensor was successfully applied to the determination of oleanolic acid in Acitinidia deliciosa root samples.     

A Novel Sensitive Electrochemical Sensor Based on Nickel Chloride Solution Modified Glassy Carbon Electrode for Curcumin Determination

In this research, the high conductivity of nickel chloride solution as well as the ability of nickel ions in establishing particular bonds with curcumin was benefited to fabricate a new electrochemical sensor based on nickel chloride solution modified glassy carbon electrode (NiCl₂/GCE) for detection and measurement of curcumin in human blood serum. Atomic force microscope (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) methods indicated that using nickel chloride solution for the modification of the glassy carbon electrode (GCE) surface had a significant effect on improvement of the electrode performance. Differential pulse voltammetry (DPV) was used for quantitative measurement of curcumin, which exhibited the linear response of NiCl₂/GCE toward curcumin within the concentration range of 10–600 μM and provided the detection limit of 0.109 μM for curcumin in human blood serum.     

纳米氧化铜修饰的苯巴比妥分子印迹传感器的制备及其电化学性能

为了改善分子印迹传感器的灵敏度, 在四丁基高氯酸铵的支持电解质溶液中, 以甲基丙烯酸为功能单体, 马来松香丙烯酸乙二醇酯为交联剂在纳米氧化铜修饰过的玻碳电极上电聚合了一种苯巴比妥(PB)识别性能的分子印迹传感膜. 采用循环伏安(CV)法、差分脉冲伏安(DPV)法及交流阻抗(EIS)法对这种纳米氧化铜修饰过的印迹及非印迹电极的电化学性能进行了研究, 结果显示纳米氧化铜修饰过的印迹及非印迹电极的电化学性能完全不同. X射线衍射(XRD)证实纳米粒子为氧化铜. 采用扫描电镜(SEM)对纳米氧化铜修饰过的印迹传感器的形貌进行分析, 发现纳米氧化铜分散在电极表面, 改善了修饰印迹传感器的识别点. 差分脉冲伏安法(DPV)表明苯巴比妥的浓度在1.0×10^-8-1.8×10^-4 mol·L^-1 范围内呈现良好的线性关系(线性相关系数R=0.9994); 检出限2.3×10^-9 mol·L^-1 (信噪比(S/N)=3). 研究结果表明纳米氧化铜修饰过的印迹传感器具有较高灵敏度及选择性. 此印迹传感器能用于实际样品中苯巴比妥的检测, 加标回收率在95.0%-102.5%.     

纳米氧化铜修饰的苯巴比妥分子印迹传感器的制备及其电化学性能

为了改善分子印迹传感器的灵敏度,在四丁基高氯酸铵的支持电解质溶液中,以甲基丙烯酸为功能单体,马来松香丙烯酸乙二醇酯为交联剂在纳米氧化铜修饰过的玻碳电极上电聚合了一种苯巴比妥(PB)识别性能的分子印迹传感膜.采用循环伏安(CV)法、差分脉冲伏安(DPV)法及交流阻抗(EIS)法对这种纳米氧化铜修饰过的印迹及非印迹电极的电化学性能进行了研究,结果显示纳米氧化铜修饰过的印迹及非印迹电极的电化学性能完全不同.X射线衍射(XRD)证实纳米粒子为氧化铜.采用扫描电镜(SEM)对纳米氧化铜修饰过的印迹传感器的形貌进行分析,发现纳米氧化铜分散在电极表面,改善了修饰印迹传感器的识别点.差分脉冲伏安法(DPV)表明苯巴比妥的浓度在1.0×10-8-1.8×10-4mol·L-1范围内呈现良好的线性关系(线性相关系数R=0.9994);检出限2.3×10-9mol·L-1(信噪比(S/N)=3).研究结果表明纳米氧化铜修饰过的印迹传感器具有较高灵敏度及选择性.此印迹传感器能用于实际样品中苯巴比妥的检测,加标回收率在95.0%-102.5%.