聚叶酸修饰电极的制备及其对肾上腺素的电催化氧化研究

采用电化学聚合的方法,将叶酸(FA)聚合在碳糊电极(CPE)表面,制备了聚叶酸修饰碳糊电极(PFA/CPE),并研究了肾上腺素(EP)在该修饰电极上的电化学行为。实验结果显示:在pH 7.0的磷酸盐缓冲溶液中,该聚合膜对EP的氧化有显著的催化作用,EP在修饰电极上产生2个氧化峰和一个还原峰,峰电位分别为0.193V、0.4184V和-0.252V。在测定实验条件下,EP在PFA/CPE上的氧化峰电流与其浓度在2.50×10-7～1.78×10-4mol/L范围内具有良好的线性关系,检出限可达1×10-7mol/L。将该电极应用于EP实际样品的测定,效果良好。     

血红蛋白在月桂酸修饰玻碳电极的电催化行为

研究血红蛋白在月桂酸修饰电极上的电化学行为,在0.02mol.L-1KH2PO4-Na2HPO4(pH=7)的缓冲液中,+0.6～-0.7V(vs.Ag/AgCl)电位范围内,Hb于该修饰电极产生不可逆还原电流峰.还原峰电流ip与v1/2呈线性关系,ip随溶液pH值和血红蛋白浓度的增加而增大,其浓度在1.00×10-8～5.00×10-9mol.L-1和1.92×10-6～2.06×10-7mol.L-1范围内分段呈线性变化关系.实验数据经进一步分析拟合,得到更精确的信息.该电极可作为检测血红蛋白的新型电化学生物传感器.     

聚L-谷氨酸修饰电极对尿酸的电催化及其应用

用循环伏安法制备了聚L-谷氨酸修饰玻碳电极,研究了尿酸在该电极上的电化学行为。实验结果表明,在pH5.0的磷酸盐缓冲溶液介质中,聚L-谷氨酸修饰玻碳电极对尿酸的氧化具有良好的电催化作用,催化氧化峰电流与尿酸的浓度在2.5×10-6~1.0×10-5mol/L范围内具有良好的线性关系,相关系数r=0.9943。利用该法直接测定人体尿样中尿酸的含量,回收率为98.2%~102.2%。     

尿酸在聚L-苯丙氨酸修饰电极上的伏安测定

采用循环伏安法制备了聚L-苯丙氨酸薄膜修饰玻碳电极,研究了尿酸在该修饰电极上的电化学行为,循环伏安法测定了尿酸. 研究发现,在pH=5.6的磷酸盐缓冲溶液中,尿酸在聚L-苯丙氨酸修饰电极上于0.43 V处产生1灵敏的氧化峰;循环伏安法测定其氧化峰电流与尿酸的浓度在2.0×10-6～3.0×10-4 mol/L呈良好的线性关系,检出限为1×10-6 mol/L. 对1.0×10-5 mol/L尿酸平行测定5次,相对标准偏差为3.0%. 该聚合物修饰电极制作简单,重现性好,可用于尿液中尿酸的测定,结果令人满意.     

脯氨酸Ni(Ⅱ)修饰电极的制备及对甲醇氧化的催化(英文)

研究了聚色氨酸修饰玻碳电极（Ｐｏｌｙ－Ｔｒｙ／ＧＣ）的制备,用循环伏安法探讨了膜的电化学性质。在ｐＨ＝６．６的ＰＢＳ中,膜的循环伏安图上有两对氧化还原峰。掺杂金属离子Ｎｉ（Ⅱ）后的该聚合物膜修饰电极（Ｐｏｌｙ－Ｎｉ（Ⅱ） Ｔｒｙ／ＧＣ）对甲醇的催化活性大大提高,在０．０１ ｍｏｌ／Ｌ ＮａＯＨ中甲醇的氧化峰电位在０．６５ Ｖ,而同样条件下在空白玻璃电极（ＧＣ）和Ｐｏｌｙ－Ｔｒｙ／ＧＣ上甲醇的氧化峰电位要正得多。在０．１５ ｍｏｌ／Ｌ甲醇溶液中循环伏安扫描１５０ ｍｉｎ后,峰电流密度由１０６０ μＡ／ｃｍ～２降低至８８５μＡ／ｃｍ～２,然后峰电流密度不再降低,说明在电催化氧化甲醇过程中电极稳定性良好。     

羟喜树碱在导电聚合物膜修饰电极上的电催化性能及其电化学分析方法研究

采用循环伏安法对羟喜树碱在4-(2-吡啶偶氮)间苯二酚(PAR)导电聚合膜修饰电极上的电催化性能及其电化学分析方法进行了研究.磷酸盐缓冲液中(pH3.0),在-0.2～ 0.4 V范围内羟喜树碱在PAR膜修饰电极表面受吸附控制,发生准可逆单电子转移电极反应过程,电子转移系数α=0.38;首次提出了以差示脉冲伏安法建立检测羟喜树碱含量的新方法.在聚合时间为40圈(100mV/s),富集电位 1.0V,富集时间240s条件下,利用差示脉冲伏安法测得其氧化峰电流Ip与浓度分别在0.01～1.0μmol/L和1.0～4.0μmol/L范围内呈良好的线性关系,检出限为1.0nmol/L.     

碳纳米管修饰电极对多巴胺和抗坏血酸的电催化氧化

研究了碳纳米管修饰玻碳电极 (NTCME)的制备方法及对多巴胺 (DA)和抗坏血酸 (AA)的电催化氧化作用。在磷酸盐缓冲溶液 (PBSpH 7.4)中 ,以NTCME为工作电极时 ,DA与AA的氧化电位分别为 0 .2 6和 0 .0 1V(vs.SCE) ,比在裸玻碳电极 (GC)上分别降低了 0 .0 7和 0 .6 2V。NTCME能消除DA与AA共存时测定的相互干扰。利用二阶导数卷积伏安法测定 ,DA与AA分别在 2 .0 0× 10 - 6～ 3.84× 10 - 4 和 7.99× 10 - 5～ 3.6 6× 10 - 3 mol L浓度范围内 ,峰高与浓度呈线性关系 ;检出限分别为 1.90× 10 - 7和 5 .96× 10 - 5mol L。     

普鲁士蓝膜修饰电极循环伏安行为的研究

本文研究普鲁士蓝(PB)膜修饰电极的循环伏安行为,结果表明,膜中电活性中心间的相互作用导致PB膜电极的伏安行为偏离理想表面波.用有限扩散边界模型解释了高电位扫速下膜电极的伏安行为.在含钾离子的电解质溶液中测得PB膜中电荷传输扩散系数为10~(-9)～10~(-11)cm~2/s.     

Nafion修饰电极测定血液中的肾上腺素

本文采用Nafion修饰玻碳电极研究了肾上腺素的循环伏安特性。完善了它的分析方法,消除了抗坏血酸的干扰,提高了灵敏度。在生理pH条件下其氧化峰电流与浓度在3.0×10~(-7)～5.0×10~(-5)mol/L范围内呈良好的线性关系,此法应用于血液样品的测定,获得了满意的结果。     

聚对氨基酚修饰电极的制备及其对尿酸的催化氧化作用

采用循环伏安法制备了聚对氨基酚薄膜修饰玻碳电极, 研究了尿酸在该修饰电极上的电化学行为, 建立了循环伏安法测定尿酸的新方法. 研究发现: 在pH 5.6的磷酸盐缓冲溶液中, 以0.1 mol/L KCl作支持电解质, 聚对氨基酚修饰电极对尿酸存在灵敏的氧化作用, 应用循环伏安法对尿酸进行定量分析, 线性范围为1.0×10-6～4.0×10-5 mol/L, 检出限为8×10-7 mol/L. 对2.0×10-5 mol/L尿酸平行测定5次, 相对标准偏差为4.0%.     

N—（3—二茂铁乙酰胺基）丙基吡咯聚合物修饰的葡萄糖电极的研究

于铂电极上修饰一层Ｎ－（３－二茂铁乙酰胺基）丙基吡咯聚合物膜，应用循环伏安法对聚合物的电化学性能进行研究，发现了Ｎ－位取代吡咯聚合物的电活性大大降低，聚合物中 二茂铁基团氧化还原性能稳定，制成酶电极后，在＋０．２Ｖ以葡萄糖有一明显的催化峰，而对抗坏血酸，尿酸则几乎没有呼应，该葡萄糖电极性能稳定，连续工作十天，响应值基本不变。     

Nickel pentacyanonitrosylferrate film modified aluminum electrode for electrocatalytic oxidation of hydrazine

The electrocatalytic oxidation of hydrazine at the aluminum electrode, modified by electroless deposition of nickel pentacyanonitrosylferrate (NiPCNF) on the surface of the electrode has been studied by cyclic voltammetry, chronoamperometry and rotating disk electrode voltammetry and the kinetics of the catalytic reaction were investigated. The results were explained using the theory of electrocatalytic reactions at chemically modified electrodes. It was found that a one-electron charge-transfer process is rate limiting and that the average values of the rate constant for the catalytic reaction and the diffusion coefficient, evaluated by different approaches, are 5.2×10³ M^–1s^–1 and 8.5×10^–6 cm²s^–1, respectively. Further examinations of the modified electrodes show that the modifying layers (NiPCNF) on the aluminum substrate have reproducible behavior and a high level of stability, after exposing them in air and hydrazine solutions for a long time. Electronic Publication     

Electrocatalytic oxidation of glucose at a Ni-curcumin modified glassy carbon electrode

The electrocatalytic oxidation of glucose was investigated on a nickel-basedchemically modified electrode (Ni(II)-curcumin) prepared by electropolymerization of Ni-curcumin complex (curcumin=1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) in alkaline solution. Reaction kinetic and mechanism were investigated by using cyclic voltammetry (CV) and chronoamperometry (CA) techniques and steady-state polarization measurements. Cyclic voltammetry studies indicated that in the presence of glucose the anodic peak current of surface redox mediator was increased, followed by decrease in the corresponding cathodic current. This indicates that glucose was oxidized at the surface of this modified electrode. The results were explained based on the concept of electrocatalytic reactions that occur in this chemically modified electrode. The diffusion coefficient of glucose and the rate constant of the catalytic oxidation of glucose were found to be 6.7×10⁻⁶ cm² s⁻¹ and 6.5×10³ M⁻¹ s⁻¹, respectively. It has shown that by using the Ni-curcumin modified electrode, glucose can be determined with good response and low detection limit.     

聚磺胺嘧啶修饰电极伏安法测定对乙酰氨基酚

利用循环伏安法制备了聚磺胺嘧啶修饰电极, 研究了对乙酰氨基酚在该修饰电极上的电化学行为. 该电极对对乙酰氨基酚有较强的电催化作用. 在pH 9.0的PBS缓冲溶液中, 用循环伏安法和差分脉冲伏安法在该电极上测定了对乙酰氨基酚, 其线性范围分别为4.0×10-6～3.0×10-4 mol/L和2.0×10-7～1.0×10-5 mol/L, 检出限分别为9.0×10-7 mol/L和8.0×10-8 mol/L.     

Electrocatalytic oxidation of glucose on Ni and NiCu alloy modified glassy carbon electrode

Nickel and nickel–copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) prepared by galvanostatic deposition were examined for their redox processes and electro-catalytic activities towards the oxidation of glucose in alkaline solutions. The methods of cyclic voltammetry (CV) and chronoamperometry (CA) were employed. The cyclic voltammogram of NiCu alloy demonstrates the formation of β/β crystallographic forms of the nickel oxyhydroxide under prolonged repetitive potential cycling in alkaline solution. It is also observed that the overpotential for O₂ evolution increases for NiCu alloy modified electrode. In CV studies, NiCu alloy modified electrode yields significantly higher activity for glucose oxidation compared to Ni. The oxidation of glucose was concluded to be catalyzed through mediated electron transfer across the nickel hydroxide layer comprising of nickel ions of various valence states. The anodic peak currents show linear dependency with the square root of scan rate. This behavior is the characteristic of a diffusion-controlled process. Under the CA regime, the reaction followed a Cottrellian behavior, and the diffusion coefficient of glucose was found to be 1 × 10⁻⁵ cm² s⁻¹, in agreement with diffusion coefficient obtained in CV studies.     

壳聚糖修饰电极上的铁氰根离子对抗坏血酸的电催化氧化作用

在玻碳电极表面滴涂一层壳聚糖膜 ,壳聚糖分子中 -NH2 在酸性溶液中发生质子化 ,靠静电引力作用吸附富集荷负电的电子介体Fe(CN) 63 -,使其固定在电极表面 ,研究了此Fe(CN) 63 - 壳聚糖 GC修饰电极对抗坏血酸的催化氧化作用。抗坏血酸的浓度在 3.0× 1 0 -6～ 5 .0× 1 0 -3 mol L范围内呈很好的线性关系 ,相关系数为 0 .998,检测限达 1 .0× 1 0 -6mol L。该法已用于测定蔬菜中抗坏血酸的含量。     

The electrocatalytic examination of cephalosporins at carbon paste electrode modified with CoSalophen

The electrocatalytic oxidation of cephalexin and cefazolin has been studied at a carbon paste electrode modified with cobalt salophen (CoSal) by cyclic voltammetry. The selectivity of the carbon paste modified with CoSal in detecting cephalexin and cefazolin was examined. To suggest the electrocatalytic mechanism for electro-oxidation of cefazolin, the electrochemical behavior of ceftriaxone was investigated which has a thiol group out of the beta lactam ring. The electrocatalytic oxidation of these antibiotics is shown to be irreversible at the CoSal modified electrode. Scan rate dependence of cefazolin, which is a sulfur-containing compound, has been examined. The results indicated that the electrocatalytic oxidation of the compounds is diffusion controlled. The responses of the modified electrode were compared with those of unmodified electrode and it has shown that the modified electrode has better sensitivity than unmodified electrode to the detection of cefazolin. The overall number of electrons contributed to the oxidation of cefazolin is obtained 1 by chronoamperometry; the number of electron involved in the rate-determining step was 1. The results of differential pulse voltammetry (DPV) using the modified electrode with high sensitivity were applied for the determination of cefazolin in human synthetic serum samples. The linear range was obtained from 1 × 10⁻⁵ to 1 × 10⁻³ M for DPV determination of cefazolin in buffered solutions (pH 3.0).     

Electrocatalytic oxidation of NADH at gold nanoparticles loaded poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) film modified electrode and integration of alcohol dehydrogenase for alcohol sensing

A new modified electrode is fabricated by dispersing gold nanoparticles onto the matrix of poly(3,4-ethylenedioxythiophene)–poly(styrene sulfonic acid), PEDOT–PSS. The electrocatalytic activity of the PEDOT–PSS-Au_nano electrode towards the oxidation of β-nicotinamide adenine dinucleotide (NADH) is investigated. A substantial decrease in the overpotential (>0.7 V) has been observed for the oxidation of NADH at the PEDOT–PSS-Au_nano electrode in comparison to the potential at PEDOT–PSS electrode. The Au nanoparticles dispersed in the PEDOT–PSS matrix prevents the fouling of electrode surface by the oxidation products of NADH and augments the oxidation of NADH at a less positive potential (+0.04 V vs. SCE). The electrode shows high sensitivity to the electrocatalytic oxidation of NADH. Further, the presence of ascorbic acid and uric acid does not interfere during the detection of NADH. Important practical advantages such as stability of the electrode (retains 95% of its original activity after 20 days), reproducibility of the measurements (R.S.D.: 2.8%; n = 5), selectivity and wide linear dynamic range (1–80 μM; R² = 0.996) are achieved at PEDOT–PSS-Au_nano electrode. The ability of PEDOT–PSS-Au_nano electrode to promote the electron transfer between NADH and the electrode makes us to fabricate a biocompatible dehydrogenase-based biosensor for the measurement of ethanol. The biosensor showed high sensitivity to ethanol with rapid detection, good reproducibility and excellent stability.     

聚对氨基苯磺酸修饰电极测定尿酸

利用循环伏安法制备了聚对氨基苯磺酸修饰电极, 研究了尿酸在该修饰电极上的电化学行为. 结果表明, 该电极对尿酸有较强的电催化作用, 并对抗坏血酸有较强的抗干扰能力. 在pH 5.6的乙酸盐缓冲溶液中, 用循环伏安法和差分脉冲伏安法在该电极上测定了尿酸, 其线性范围分别为1.0×10-5～2.0×10-4 mol/L和4.0×10-7～1.0×10-5 mol/L, 检出限分别为6.0×10-6 mol/L和1.0×10-7 mol/L. 已用于尿液中尿酸的测定.