Electrochemical Study and Selective Determination of Dopamine at a Multi-Wall Carbon Nanotube-Nafion Film Coated Glassy Carbon Electrode

A homogeneous and stable suspension of multi-wall carbon nanotubes (MWNT) was achieved by dispersing MWNT into 0.1% Nafion ethanol solution. A uniform MWNT-Nafion cast film was obtained over a glassy carbon electrode (GCE) via solvent evaporation. The electrochemical behavior of dopamine (DA) was examined, and a reversible two-electron redox reaction was observed. In comparison with the bare GCE and the Nafion-modified GCE, the MWNT-Nafion modified GCE shows obvious electrocatalytic activity towards DA. Moreover, the MWNT-Nafion film coated electrode exhibits excellent selectivity towards DA even in the presence of high concentrations of ascorbic acid (AA) and uric acid (UA). The oxidation peak current was proportional to the concentration of DA over the range of 1×10^–8 to 1×10^–5molL^–1, and a detection limit of 2.5×10^–9molL^–1 was obtained after 2min. of open-circuit accumulation. The dispersion and morphology of MWNT-Nafion film were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transfer (FT) IR spectra.     

对乙酰氨基酚在分子印迹膜修饰玻碳电极上的电化学行为及测定

以对乙酰氨基酚（PCT）为模板分子,甲基丙烯酸为功能单体,采用光引发原位聚合法在玻碳电极（GCE）表面聚合成膜,以甲醇-甲酸将模板分子洗脱,制得对乙酰氨基酚分子印迹膜修饰电极（MIP-GCE）,建立了该电极直接测定PCT的分析方法。结果表明,该传感器具有较高的选择性和灵敏度,PCT浓度在5.0×10-5~1.0×10-3 mol?L-1范围内与其峰电流呈良好的线性关系,检出限为1.4×10-6 mol?L-1。应用该法测定药物中PCT的含量,在干扰物质共存情况下的回收率为96%~105%。     

Selective and Sensitive Determination of Paracetamol and Levodopa with Using Electropolymerized 3,5-Diamino-1,2,4-triazole Film on Glassy Carbon Electrode

For determination of levodopa (L-DOPA) and paracetamol (PAR), selective, effective and sensitive electrochemical sensor based on 3,5-diamino-1,2,4-triazole (35DT) on glassy carbon (GC) electrode was reported. The DPV method was used to obtain the oxidation peak current of L-DOPA which increased linearly with its concentration at the range of 1–99 μM and 99–480 μM. The linear relationship between the concentration of PAR and its peak current was obtained in the range of 0.3–55 μM and 55–475 μM. The limit of detection values for PAR and L-DOPA were found to be 0.1 and 0.25 μM, respectively. Satisfactory results were obtained in pharmaceutical samples.     

The Mn‐zeolite/Graphite Modified Glassy Carbon Electrode: Fabrication,Characterization and Analytical Applications

In this work, low‐cost and environmentally friendly natural zeolite exchanged with Mn²⁺ cations was used for the first time to modify the glassy carbon electrode with the aim to obtain a fast and simple sensor for voltammetric determination of paracetamol (PAR). The Mn‐zeolite/graphite modified glassy carbon electrode (MnZG?GCE) was prepared by evaporation of solvent from dispersion of the zeolite/graphite mixture with the polymer in acetone. The electrochemical characteristics of MnZG?GCE were conducted by electrochemical impedance spectroscopy and cyclic voltammetry. Compared with graphite modified GCE (G?GCE), MnZG?GCE exhibited better electrochemical parameters, which confirms the superiority of applying zeolite in the proposed sensor. The optimization of the pH‐value of supporting electrolyte and instrumental parameters were carried out. The peak current was proportional to the concentration of PAR in a phosphate buffer saline of pH 6.0 in the range from 0.029 to 0.69 mg L^?1 (R=0.9997) with limit of detection of 8.8 μg L^?1. Finally, the proposed electrode was successfully applied to determine the paracetamol in pharmaceutical formulation and certified reference materials. The satisfactory recoveries, which ranged from 89.2 to 102.7 %, were obtained for all studied samples. It confirmed the attractiveness of relatively inexpensive, easy to fabricate and non‐toxic MnZG?GCE in determination of PAR in complicated matrixes.     

Electroanalytical Determination of Paracetamol Using Pd Nanoparticles Deposited on Carboxylated Graphene Oxide Modified Glassy Carbon Electrode

The study presents a novel paracetamol (PA) sensor based on Pd nanoparticles (PdNPs) deposited on carboxylated graphene oxide (GO?COOH) and nafion (Nf) modified glassy carbon electrode (GCE). The morphologies of the as prepared composites were characterized using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and fourier transform infrared spectroscopy (FTIR). The experimental results demonstrated that Nf/GO?COOPd displayed excellent electrocatalytic response to the oxidation PA. The linear range was 0.04–800 μM for PA with limit of detection of 0.012 μM and excellent sensitivity of 232.89 μA mM^?1 cm^?2. By considering the excellent performance of Nf/GO?COOPd composite such as wider linear range, lower detection, better selectivity, repeatability, reproducibility, and storage stability, the prepared composite, especially GO?COOH support, with satisfactory electrocatalytic properties was a promising material for the modification of electrode material in electrochemical sensor and biosensor field.     

对乙酰氨基酚在活化玻碳电极上的电化学行为及测定

应用循环伏安法,研究了对乙酰氨基酚(PCT)在活化玻碳电极上的电化学行为.在pH=4.00的HAc-NaAc缓冲溶液中,PCT的CV扫描于0.54 V左右出现一对明显的氧化-还原峰.电极反应为2电子、2质子的受吸附控制的准可逆过程.其氧化峰电流与PCT浓度在8.00×10-6~2.00×10-4mol.L-1范围内呈良好的线性关系,相关系数r=-0.99918;检出限为6.34×10-6mol.L-1.用于药物样品PCT的含量测定,结果满意.     

A Sensitive Simultaneous Determination of Adrenalin and Paracetamol on a Glassy Carbon Electrode Coated with a Film of Chitosan/Room Temperature Ionic Liquid/Single‐Walled Carbon Nanotubes Nanocomposite

The present work demonstrates that simultaneous determination of adrenalin (AD) and paracetamol (PAR) can be performed on single‐walled carbon nanotube/chitosan/ionic liquid modified glassy carbon electrode (SWCNT‐CHIT‐IL/GCE). The electro‐oxidations of AD and PAR were investigated with cyclic voltammetry (CV), differential pulse voltammetry (DPV) and also chronoamperometry (CA) methods. DPV experiments showed that the oxidation peak currents of AD and PAR are proportional to the corresponding concentrations over the 1–580 μmol/L and 0.5–400 μmol/L ranges, respectively. The RSD at a concentration level of 15 μmol/L AD and 15 μmol/L PAR were 1.69% and 1.82%, respectively. Finally the modified electrode was used for simultaneous determination of AD and PAR in real samples with satisfactory results.     

Sensitive Electrochemical Detection of Bisphenol A Using Molybdenum Disulfide/Au Nanorod Composites Modified Glassy Carbon Electrode

Bisphenol A, an important compound that is classified as an environmental hormone, has been proven to have harmful effects on human health and ecology. A molybdenum disulfide/Au nanorod‐modified glassy carbon electrode was prepared as an electrochemical sensor for the detection of bisphenol A using a simple and convenient approach. UV–Vis spectrophotometry and transmission electron microscopy were employed to characterize the composite. The electrochemical behavior of bisphenol A at the modified electrode was investigated via differential pulse voltammetry and cyclic voltammetry. The results show that bisphenol A exhibits a good electrochemical signal at the modified electrode under optimized conditions, and a good linear relationship was observed between the bisphenol A concentration and peak current within the range of 0.01–50 μM, with a detection limit of 3.4 nM. Furthermore, the fabricated electrodes showed good anti‐interference, reproducibility and stability. The proposed electrochemical method was successfully applied for the detection of bisphenol A in milk and water samples, and its potential for applications in pollutant detection was demonstrated.     

Glassy Carbon Electrode Modified via Molybdenum Disulfide Decorated Multiwalled Carbon Nanotubes for Sensitive Voltammetric Detection of Aristolochic Acids

In this study, a molybdenum disulfide/multiwalled carbon nanotubes (MoS₂@MWCNTs) nanocomposite was synthesized by employing a simple hydrothermal method. The flower‐like structure of the MoS₂@MWCNTs was characterized via scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the load of crystalline MoS₂ was verified via X‐ray diffraction (XRD) and energy‐dispersive spectroscopy (EDS). The as‐prepared MoS₂@MWCNTs nanocomposite was used to modify glassy carbon electrode (GCE) as an electrochemical sensor for detecting aristolochic acids (AAs). With the optimized parameters, the proposed electrochemical sensor exhibited good sensitivity and a broad linear concentration range for detecting AAs from 0.2 to 10 μ mol/L and 10 to 100 μ mol/L, with the sensitivity of ?3.10 μ A/(μ mol/L) and ?0.91 μ A/(μ mol/L), respectively. The detection limit was also calculated as 0.06 μ mol/L (S/N=3) based on the low background signal. Furthermore, the modified electrochemical sensor exhibited good selectivity, repeatability, reproducibility, and stability, thus showing potential application for detecting AA in chinese herbs with good mean recovery and accuracy. In other words, the MoS₂@MWCNTs/GCE can be used as an excellent platform to detect AAs.     

Electrocatalytic Oxidation of Dopamine by Ferrocene in Lipid Film Cast on a Glassy Carbon Electrode

ＩｎｔｒｏｄｕｃｔｉｏｎＤＡｉｓｏｎｅｏｆｅｓｓｅｎｔｉａｌｐａｒｔｉｃｉｐａｎｔｓｉｎｔｈｅｎｅｕｒｏ ｔｒａｎｓｍｉｓｓｉｏｎｐｒｏｃｅｓｓｉｎｍａｍｍａｌｉａｎｃｅｎｔｒａｌｎｅｒｖｏｕｓｓｙｓ ｔｅｍ .ＡｌｏｓｓｏｆＤＡ ｃｏｎｔａｉｎｉｎｇｎｅｕｒｏｎｓｍａｙｒｅｓｕｌｔｉｎｓｏｍｅｓｅｒｉｏｕｓｄｉｓｅａｓｅｓｕｃｈａｓＰａｒｋｉｎｓｏｎｉｓｍ .1Ｓｉｎｃｅｉｔｓｄｉｓｃｏｖ ｅｒｙｉｎｔｈｅ 195 0ｓ ,ＤＡｈａｓｂｅｅｎｏｆｉｎｔｅｒｅｓｔｔｏｎｅｕｒｏｓｃｉｅｎ ｔｉｓｔｓａｎｄｃｈｅｍ…     

氯霉素分子印迹聚合膜电极的制备及氯霉素检测

以邻氨基酚(OAP)为功能单体,氯霉素(CAP)为模板分子,用电化学聚合的方法在Pt上合成了CAP分子印迹（MIP）OAP膜(CAP-MIP-OAP/Pt)电极,通过扫描电子显微镜和电化学技术对聚合膜的结构和性能进行了表征。 结果表明,该膜电极对CAP检测有较好的选择性和灵敏度,CAP检测的线性范围为4.33×10-8～3.09×10-6 mol/L,检出限为2.5×10-8 mol/L。     

新法制备铁氰化钴修饰玻碳电极及多巴胺的电催化氧化

新法制备铁氰化钴修饰玻碳电极及多巴胺的电催化氧化     

单壁碳纳米管-氨基二茂铁复合物修饰玻碳电极对对硝基苯酚的电化学检测

本研究用氨基二茂铁(Aminoferrocene,AFc)经重氮化反应后修饰单壁碳纳米管(SWNTs),制备SWNTs-AFc复合物,并以该复合物修饰玻碳电极(GCE),通过循环伏安法(CV)和差分脉冲伏安法(DPV)等电化学方法检测对硝基苯酚(p-NP)。结果表明,与裸玻碳电极相比,SWNTs-AFc/GCE对p-NP响应的还原过电位显著减小,峰电流大大增强,p-NP的检测线性范围为1~850μmol/L(R2=0.997),检测限为1μmol/L。该方法电流响应快、灵敏度高、检测限低,具有良好的应用前景。     

Keggin 型磷钨酸盐修饰碳糊电极传感多巴胺的研究

多金属氧酸盐作为一类阴离子簇合物,由于其结构的多样性和尺寸大小的可调变性,在电化学、催化和药学等领域引起了人们的广泛关注.本文制备了多酸Co(C₁₅N₆H₁₂)₂[PW₁₂O₃₈]·5H₂O（Co[PW₁₂O₃₈]）修饰碳糊电极并通过电化学阻抗谱、循环伏安法以及差分脉冲伏安法对多巴胺的传感性能进行了研究.对其制备条件和检测条件分别进行了优化.在优化条件下,制备的传感器对多巴胺具有良好的选择性和灵敏度的检测能力.多巴胺的线性响应范围为8.0x10^-6 mol·L^-1至3x10^-5 mol·L^-1,灵敏度为0.039 μA·(μmol·L^-1)^-1,检出限（S/N=3）为5.4 x10^-6 mol·L^-1. 制备的多酸修饰碳糊电极用于检测多巴胺表现出良好的稳定性和重现性,并且对抗坏血酸、尿酸等常见的干扰物质,具有良好的抗干扰性. 多酸修饰的碳糊电极制备过程简单方便,成本低,传感性能良好,对应用于电化学传感器检测多巴胺具备潜在的应用前景.      

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.     

聚伊文思蓝修饰电极对多巴胺和抗坏血酸的电分离及同时测定

研究多巴胺(DA)和抗坏血酸(AA)在聚伊文思蓝(Evans Blue)修饰电极上的伏安行为,建立差示脉冲伏安测定法.在pH4.5磷酸盐缓冲液中,聚伊文思蓝修饰电极对DA和AA有显著的增敏和电分离作用.DA和AA氧化峰电流与浓度分别在1.0×10-6~3.0×10-5mol/L和5.0×10-6~1.05×10-4mol/L范围内呈良好的线性关系,检测限分别为2.5×10-7mol/L和3.0×10-7mol/L.当DA与AA共存时,由该修饰电极检测的二者氧化峰电位差达184 mV,故可同时测定DA和AA,并有效消除其它组分对DA测定的干扰,已用于实际样品中DA和AA含量的测定,结果令人满意.     

The New Application of Boron Doped Diamond Electrode Modified with Nafion and Lead Films for Simultaneous Voltammetric Determination of Dopamine and Paracetamol

A new voltammetric procedure for the simultaneous determination of dopamine (DA) and paracetamol (PA) using boron doped diamond electrode modified with Nafion and lead films (PbF/Nafion/BDDE) was investigated. The use of this electrode resolved the overlapped voltammetric waves of DA and PA into well‐defined peaks with peak to peak separation of about 320 mV. Under the optimized experimental conditions in differential pulse voltammetric technique, DA and PA gave a linear response over the ranges 2.0×10^?7–1.0×10^?4 mol L^?1*(R²=0.9996) and 5.0×10^?7–1.0×10^?3 mol L^?1 (R²=0.9979), respectively. The detection limits were found to be 5.4×10^?8 mol L^?1 for DA and 1.4×10^?7 mol L^?1 for PA. They are lower, comparable or in some cases a little bit higher than those obtained using other electrochemical sensors. However, the proposed procedure of the sensor preparation is much simpler than procedures described in the literature with a lower detection limit. The proposed procedure was successfully applied to the determination of PA in some commercial pharmaceuticals as well as to the simultaneous determination of DA and PA in human urine, whole blood and serum samples directly without any separation steps.     

聚三聚氰胺-石墨烯复合膜修饰电极对多巴胺与尿酸的同时测定

采用循环伏安法制备了聚三聚氰胺-石墨烯复合膜修饰电极(poly-(MA)-ERGO/GCE)。研究了抗坏血酸(AA)、尿酸(UA)和多巴胺(DA)在该修饰电极上的电化学行为。结果表明,该修饰电极对AA、UA和DA均有良好的电化学响应,且三者的氧化峰在该修饰电极上可完全分离。据此建立了在大量AA存在下同时测定UA和DA的新方法。在优化条件下,微分脉冲伏安法(DPV)测定UA和DA的线性范围均为1.0×10~(-8)~5.0×10-6mol·L~(-1),检出限(3sb)均为5.0×10~(-9)mol·L~(-1)。     

以Nafion修饰的镀铂玻碳电极为基底的半乳糖传感器的制备

在镀铂的玻碳电极表面,修饰一层全氟代磺酸酯(Nafion)膜,制成基底电极。用化学交联法将半乳糖氧化酶(GAD)固定在基底电极表面,即制成半乳糖传感器。和光亮铂相比,镀铂电极对过氧化氢有更高的响应,而Nafion膜可以消除抗坏血酸,尿酸等电活性物质对测定的影响,提高了酶电极测定的选择性。D-半乳糖测定的线性范围为0.25～4.25 mmol/L,响应时间小于30s。电极连续使用300次,没有明显的电流变化。该电极具有快速、准确,选择性高的特点。     

Electrochemical Characterization of Polymerized Cresol Red Film Modified Glassy Carbon Electrode and Separation of Electrocatalytic Responses for Ascorbic Acid and Dopamine Oxidation

A cresol red modified glassy carbon electrode was prepared using an electrochemical method. The cyclic voltammograms of the modified electrode indicate the presence of a couple of well-defined redox peaks, and the formal potential shifts in the negative direction with increasing solution pH. The modified electrode exhibits high electrocatalytic activity toward ascorbic acid oxidation, with an overpotential of 300 mV less than that of bare glassy carbon electrodes, and drastic enhancement of the anodic currents. The calibration graph obtained by linear sweep voltammetry for ascorbic acid is linear in the range of 50∼500 µM. The electrode markedly enhances the current response of dopamine and can separate the electrochemical responses of ascorbic acid and dopamine. The separation between the anodic peak potentials of ascorbic acid and dopamine is 190 mV by cyclic voltammetry. The linear sweep voltammetric peak currents for dopamine in the presence of 2 mM ascorbic acid vary linearly with a concentration of between 10 and 100 µM.