Electrochemical Behavior of Dopamine at Poly( Methylene Blue)/Graphene Modified Glassy Carbon Electrode

利用电聚合方法在石墨烯修饰的玻碳电极表面制备了聚亚甲基蓝/石墨烯修饰电极( PMB/GH/GCE).采用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了多巴胺(DA)和抗坏血酸(AA)在该修饰电极上的电化学行为.在pH 6.9的磷酸盐缓冲溶液中,DA和AA分别在0.208 V和-0.108 V处产生灵敏的氧化峰,与其在聚亚甲基蓝和石墨烯单层修饰电极上的电化学行为相比,两者的峰电流明显增加,峰电位差达316 mV.研究表明,电聚合方法使亚甲基蓝牢固地非共价修饰到石墨烯上,并产生协同增效作用,较好地提高了电极的灵敏度和分子识别性能,有利于在大量AA存在下实现对DA的选择性测定.在1.00×10-3 mol/L AA的存在下,DA的差分脉冲伏安法峰电流与其浓度在1.00×10--7～5.00×10-3 mol/L范围内呈良好的线性关系,检出限达1.00 × 10-6mol/L.将该方法用于盐酸多巴胺注射液的测定,结果满意.     

分子印迹电化学传感器同时测定尿液中多巴胺和抗坏血酸

制备了同时检测多巴胺(DA)和抗坏血酸(AA)的分子印迹电化学传感器。该传感器以酸性铬蓝K(ACBK)为功能单体,DA/AA为模板分子,利用电化学聚合方法在电极表面合成分子印迹聚合物膜,根据DA和AA产生的氧化电流,利用差分脉冲伏安法实现DA和AA的同时测定,且DA和AA的氧化峰电位分开近300 m V。DA和AA检测限分别达6.20×10-11mol/L和1.65×10-8mol/L。传感器可应用于人尿液中DA和AA的测定。     

聚茜素红功能化碳纳米管修饰电极对多巴胺和抗坏血酸的电化学研究

采用电聚合方法将茜素红非共价修饰到碳纳米管上,制备了聚茜素红/碳纳米管修饰电极.以多巴胺(DA)和抗坏血酸(AA)为模型化合物,研究该修饰电极的电催化作用.结果表明:电聚合法使茜素红牢固地修饰到碳纳米管上,能显著提高电极的灵敏度和分子识别性能.DA和AA的氧化峰位分离达240 mV.在AA的存在下,DA的差分脉冲伏安法峰电流在1×10-7～1×10-5 mol/L范围内呈良好的线性关系,检测下限达1×10-7 mol/L.     

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.     

桑色素/石墨烯修饰电极的制备及对多巴胺的选择性灵敏测定

在石墨烯纳米片修饰电极(GN/GCE)上,通过电聚合的方法制备了新颖的桑色素/石墨烯复合修饰电极(M/GN/GCE).以多巴胺(DA)和抗坏血酸(AA)为模型化合物,运用循环伏安法(CV)和差示脉冲伏安法(DPV)考察了该复合修饰电极的电催化行为.在pH 7.0的PBS中,DA和AA分别在0.172 V和-0.183 V产生氧化峰,峰位差达355 mV.与单一修饰电极(桑色素修饰电极(M/GCE)、石墨烯修饰电极(GN/GCE)及裸玻碳电极(GCE))相比,DA在M/GN/GCE上的峰电流显著增大.在优化的实验条件下,DA在2.0×l0-8～5.5×10-4 mol/L浓度范围内与其峰电流具有良好的线性关系,检出限达9.0×10-9 mol/L.     

纳米NiO-还原石墨烯复合修饰玻碳电极的制备及电催化检测多巴胺

制备了纳米NiO-还原石墨烯复合修饰电极(NiO-rGO/GCE),并用于多巴胺(DA)的检测。用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了DA在该修饰电极上的电化学行为。结果表明,在pH=7.0的磷酸盐缓冲溶液(PBS)中,该修饰电极对DA有良好的催化作用。DA浓度在5.0×10-7~3.2×10-5 mol/L范围内与氧化峰电流呈良好的线性关系,检出限为3.8×10-8 mol/L。用该修饰电极直接测定了血清中DA含量,回收率在97.8%~101.1%之间。     

纳米金/石墨烯修饰电极的制备及其对多巴胺的测定

利用电化学还原方法制备纳米金/石墨烯修饰玻碳电极,研究了多巴胺(DA)在该修饰电极上的电化学行为,建立了电化学测定多巴胺的新方法。结果表明,在磷酸盐缓冲溶液中,此修饰电极对多巴胺的电化学响应具有很好的催化作用。利用差示脉冲伏安技术对多巴胺的电化学氧化进行定量分析,多巴胺的氧化峰电流与其浓度在1.0×10-7～1.0×10-5mol/L范围内呈良好的线性关系,检测限低至4.0×10-8mol/L。该修饰电极适于多巴胺的分析检测。     

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)。     

多巴胺在牛磺酸修饰玻碳电极上的电化学行为及其分析应用

采用电化学聚合法制备了牛磺酸修饰玻碳电极,研究了多巴胺在聚牛磺酸修饰电极上的电化学行为,建立了测定痕量多巴胺的新方法.在pH 7.2的磷酸盐缓冲溶液中,多巴胺在修饰电极上产生一对灵敏的氧化还原峰,采用差分脉冲伏安法测定,其氧化峰电流与多巴胺浓度在8.0×10-8～1.0×10-4 mol/L范围内呈良好的线性关系,检出限为1.0×10-8 mol/L.     

芦丁修饰电极研究多巴胺的电化学响应

通过循环伏安法(CV)制备了芦丁修饰电极,研究多巴胺(DA)在修饰电极上的电化学行为.结果表明,芦丁修饰膜对DA的氧化有明显的催化作用,并且可以消除抗坏血酸(AA)对DA测定的干扰.DA的浓度在1.0×10-7～9.5×10-6 mol/L范围内与其氧化峰电流呈线性关系,相关系数为0.9996,检出限为1.0×10-8 mol/L.将该修饰电极用于注射液样品中DA的测定,结果表明该修饰电极可用于实际样品分析.     

A Selective Voltammetric Method for Detecting Dopamine at Quercetin Modified Electrode Incorporating Graphene

The development of a quercetin‐graphene composite‐modified glassy carbon electrode (Qu/GH/GCE) for the selective and sensitive detection of dopamine (DA) is described in this paper. To fabricate the Qu/GH/GCE, graphene (GH) was first coated onto the surface of a glassy carbon electrode (GCE) and then quercetin (Qu) was electrodeposited on the GH matrix. Transmission electron microscopy (TEM) was used to characterize the morphology of the obtained GH and Qu/GH, and the electrochemical properties of the modified electrode were studied using electrochemical techniques. The as‐prepared Qu/GH/GCE occupied a synthetic property between GH and Qu. The common overlapped electrochemical oxidation peaks of DA and AA were completely separated and a remarkable increasing electron‐oxidation current of DA occurred on the Qu/GH/GCE, which enabled the sensitive and selective electrochemical detection of DA in the presence of ascorbic acid (AA) with peak difference of ca. 452 mV between DA and AA. The peak current obtained at 0.174 V (vs. saturated calomel electrode, SCE) from differential pulse voltammetry (DPV) is linearly dependent on the DA concentration in the range from 3.0×10^?8 to 4.0×10^?4 mol/L with a detection limit of 1.0×10^?8 mol/L. Furthermore, the Qu/GH/GCE exhibits good reproducibility and stability, and has been used for the determination of DA in samples of rat’s striatum tissue with satisfactory results.     

聚对氨基苯磺酸/石墨烯复合修饰电极对尿酸的选择性灵敏测定

采用电聚合方法在石墨烯纳米片(GN)的表面聚合一层聚对氨基苯磺酸(PABSA),制备了聚对氨基苯磺酸/石墨烯复合修饰玻碳电极(PABSA/GN/GCE)。研究了尿酸(UA)和抗坏血酸(AA)在该修饰电极上的电化学行为。与聚对氨基苯磺酸修饰电极(PABSA/GCE)及石墨烯单层膜修饰电极(GN/GCE)相比,复合修饰电极PABSA/GN/GCE显著提高了对UA和AA的检测灵敏度和分离度。在0.1 mol/L磷酸盐缓冲溶液(pH7.0)中,UA和AA的峰电位差达344 mV,表明PABSA/GN/GCE能实现对UA的选择性测定。UA的峰电流与其浓度呈良好的线性关系,线性范围为1.0×10-7～8.0×10-4mol/L,检出限为4.5×10-8mol/L。该复合修饰电极用于尿样中尿酸的测定,结果满意。     

石墨烯修饰玻碳电极用于急性早幼粒细胞白血病PML/RARa融合基因的检测

应利用电化学还原法将固定在玻碳电极表面的氧化石墨还原为石墨烯,然后再利用偶联活化剂将氨基修饰的急性早幼粒细胞白血病（APL）PML／RARα融合基因序列探针固定到石墨烯修饰电极表面,以亚甲基蓝（MB）为电化学杂交指示剂,并由差分脉冲伏安法检测人工合成APL的PML／RARα融合基因.结果表明,石墨烯对MB的检测信号起到了很好的增敏作用,杂交前后MB还原峰电流差值与靶标链DNA浓度在5×10-10~2.5×10-9 mol/L范围内呈线性关系,检出限为8×10-11 mol/L.该方法简单、特异性好,有望用于实际样品的检测.     

聚次甲基蓝修饰玻碳电极测定叶酸

利用循环伏安法将次甲基蓝修饰到玻碳电极表面,制备了聚次甲蓝修饰电极(PMB/GCE),并研究了此电极的化学性质及对叶酸的电化学响应特性.在磷酸盐缓冲液中PMB/GCE电极对叶酸有良好的催化作用并出现一个灵敏的还原峰,用循环伏安法测得峰电流与叶酸的浓度在0.1×10-3～2.9×10 -3 mol/L范围内呈良好线性关系...     

聚对氨基苯磺酸修饰电极对桑枝中桑色素的灵敏测定

采用电聚合的方法制备了聚对氨基苯磺酸(PABSA)修饰电极,以循环伏安法和差分脉冲伏安法研究了桑色素在该修饰电极上的电化学行为。PABSA和黄酮类药物桑色素的π-π共轭作用使得桑色素在该修饰电极上产生的氧化峰更加灵敏。实验发现,在pH 7.0的磷酸盐缓冲介质中,桑色素在0.214 V处产生灵敏的氧化峰。在优化实验条件下,采用差分脉冲伏安法对桑色素进行定量测定,桑色素的氧化峰电流与其浓度呈良好的线性关系,线性范围为5.0×10-7~1.0×10-3 mol/L,检出限为1.0×10-7 mol/L。将该修饰电极用于桑枝生物样品中桑色素含量的测定,结果满意。该方法具有灵敏度高、重现性好的特点,且该修饰电极稳定性高,可重复使用。     

A chitosan-multiwall carbon nanotube modified electrode for simultaneous detection of dopamine and ascorbic acid.

A chemically modified electrode based on a chitosan-multiwall carbon nanotube (MWNT) coated glassy carbon electrode (GCE) is described, which exhibits an attractive ability to determine dopamine (DA) and ascorbic acid (AA) simultaneously. The modified electrode exhibited a high differential pulse voltammetry (DPV) current response to DA at 0.144 V and AA at -0.029 V (vs. SCE) in a 0.1 mol l(-1) phosphate buffer solution (pH = 7.2). The properties and behaviors of the chitosan-multiwall carbon nanotube modified electrode (MC/GCE) were characterized using cyclic voltammetry (CV) and DPV methods. The mechanism for the discrimination of dopamine from ascorbic acid at MC/GCE is discussed. The linear calibration range for DA and AA were 5 x 10(-7) mol l(-1) to 1 x 10(-4) mol l(-1) (r = 0.997), and 5 x 10(-6) mol l(-1) to 1 x 10(-3) mol l(-1) (r = 0.996), respectively. The MC/GCE showed good sensitivity, selectivity and stability.     

Covalent modification of glassy carbon electrodes with beta-alanine for voltammetric separation of dopamine and ascorbic acid.

beta-Alanine was covalently grafted on a glassy carbon electrode (GCE) by amine cation radical formation in the electrooxidation process of the amino-containing compound. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) proved the immobilization of beta-alanine monolayer on GCE. The electrode shows strong electrocatalytic functions to dopamine (DA) and ascorbic acid (AA), reducing the overpotentials by 0.20 V and 0.23 V, respectively. Due to its different catalytic effects toward DA and AA, the modified electrode resolved the overlapping voltammetric responses of DA and AA into two well-defined voltammetric peaks by CV or differential pulse voltammetry (DPV), which can be used for the simultaneous determination of these species in a mixture. The catalytic peak current obtained from DPV was linearly related to DA and AA concentrations in the ranges of 4.0 x 10(-6)-5.0 x 10(-4) mol/L and 2.0 x 10(-5)-6.0 x 10(-3) mol/L with correlation coefficients of 0.997 and 0.995, respectively. The detection limits (3 sigma) for DA and AA were 2.4 x 10(-6) mol/L and 1.2 x 10(-5) mol/L, respectively. The electrode shows good sensitivity, selectivity and stability, and has been applied to the determination of DA and AA simultaneously in samples with satisfactory results.     

在抗坏血酸存在下用L-赖氨酸修饰玻碳电极测定多巴胺

采用电化学氧化法制备了L-广赖氮酸单分子层修饰玻碳电极,研究了多巴胺（DA）和抗坏血酸（AA）在该电极上的电化学行为。结果表明,L-广赖氨酸单分子层修饰玻碳电极不仅能改善多巴胺和抗坏血酸的电化学行为,而且能将多巴胺和抗坏血酸二者在裸电极上的完全重叠的单氧化峰分开成为两个完全独立的氧化峰,循环伏安（CV）图上峰间距为507mV,差分脉冲伏安（DPV）图上峰间距为460mV,由此可实现在AA的共存下对样品中的DA进行选择性测定。     

Enhanced sensing of dopamine in the present of ascorbic acid based on graphene/poly(p-aminobenzoic acid) composite film

Graphene/p-aminobenzoic acid composite film modified glassy carbon electrode (Gr/p-ABA/GCE) was first employed for the sensitive determination of dopamine (DA). The electrochemical behavior of DA at the modified electrode was investigated by cyclic voltametry (CV), differential pulse voltametry (DPV) and amperometric curve. The oxidation peak currents of DA increased dramatically at Gr/p-ABA/GCE. The modified electrode was used to electrochemically detect dopamine (DA) in the presence of ascorbic acid (AA). The Gr/p-ABA composite film showed excellent electrocatalytic activity for the oxidation of DA in phosphate buffer solution (pH 6.5). The peak separation between DA and AA was large up to 220 mV. Using DPV technique, the calibration curve for DA determination was obtained in the range of 0.05-10 μM. The detection limit for DA was 20 nM. AA did not interfere with the determination of DA because of the very distinct attractive interaction between DA cations and the negatively Gr/p-ABA composite film. The proposed method exhibited good stability and reproducibility.     

Preparation of aminylferrocene/nanogold modified glassy carbon electrode and its electrocatalysis on dopamine

Aminylferrocene(FcAI)-Nanogold(NG) modified glassy carbon electrode (FcAI/NG/GCE) was prepared by the Au-N bond between Au and FcAI. Electrochemical impedance spectroscopy (EIS) was employed to study the surface of the modified electrode. The electrochemical behavior of dopamine (DA) on the modified electrode was investigated and it was found that the modified electrode had an obvious electrocatalytic effect on DA. Compared with a bare GCE, the modified electrode exhibited an apparent shift of the oxidation peak potential in the negative potential direction and a marked enhancement in the current response for DA. We investigated the determination of DA on the modified electrode by differential pulse voltammetry (DPV). Linear calibration curve was obtained in the range of 7.0 x 10(-7) mol/L to 6x10(-4) mol/L of DA in 0.1 mol/L phosphate buffer solution (pH = 7.0) with a correlation coefficient of 0.9989. The detection limit (S/N = 3) of DA was estimated to be 1.0 x 10(-7) mol/L. Especially, by using the modified electrode, we can separate the oxidation peaks of ascorbic acid (AA) and DA in the PBS and it was satisfactory for the determination of DA with the interference of AA.