Voltammetric determination of cysteamine at multiwalled carbon nanotubes paste electrode in the presence of isoproterenol as a mediator

A sensitive electrochemical sensor for the determination of cysteamine(CA) was developed using a modified multiwall carbon nanotube paste electrode(MWCNTPE) with isoproterenol(ISPT) as a mediator.This modified electrode showed very high electrocatalytic activity for the anodic oxidation of CA.Under the optimized conditions,the electrocatalytic peak current showed a linear relationship with CA concentration in the range of 0.3–450.0 mmol/L with a detection limit of 0.09 mmol/L CA.The modified electrode was used for the determination of CA in real samples such as urine and drug samples.     

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.     

Homogeneous and nanomolar detection of hydrazine by indigocarmine as a mediator at the surface of TiO2 nanoparticles modified carbon paste electrode

The homogeneous electrocatalytic oxidation of hydrazine（HZ） has been studied by indigocarmine（IND） as a mediator at the surface of TiO₂ nanoparticles modified carbon paste electrode（TNMCPE）.Cyclic voltammetry was used to study the electrochemical behavior of IND at different scan rates.The voltammetric response of the modified electrode was linear against the concentration of HZ in the ranges of 3.0×l0^-8-7.0×10⁶ mol/L with differential pulse voltammetry method.The detection limit（3σ） was determined as 27.3 nmol/L.To evaluate the applicability of the proposed method to real samples,the modified CPE was applied to the determination of HZ in water samples.     

Electroanalysis and simultaneous determination of 6-thioguanine in the presence of uric acid and folic acid using a modified carbon nanotube paste electrode

The present work describes the preparation and characterization of a carbon nanotube paste electrode modified with 2,7-bis(ferrocenyl ethyl)fluoren-9-one (2,7-BF). This electrode showed an efficient catalytic activity for the electro-oxidation of 6-thioguanine (6-TG), which leads to lowering 6-TG overpotential by more than 610 mV. Also, the values of catalytic rate constant (k = 2.7 × 10(3) mol(-1) L s(-1)), and diffusion coefficient (D = 2.7 × 10(-5) cm(2) s) were calculated. In 0.1 M phosphate buffer solution of pH 7.0, the oxidation current increased linearly with two concentration intervals of 6-TG, one is 0.06 to 10.0 μmol L(-1) and the other is 10.0 to 160.0 μmol L(-1). The detection limit (3σ) obtained by differential pulse voltammetry (DPV) was 22.0 nmol L(-1). DPV was used for simultaneous determination of 6-TG, uric acid (UA) and folic acid (FA) at the modified electrode, and for quantification of 6-TG, UA and FA in some real samples by the standard addition method.     

基于纳米结构的电化学传感器同时测定溶液中异丙肾上腺素、尿酸和叶酸的浓度(英文)

A carbon paste electrode modified with 2‐((7‐(2,5-dihydrobenzylideneamino)heptylimino)methyl) benzene‐1,4‐diol(DHB) and carbon nanotubes were used to simultaneously determine the concen-trations of isoproterenol(IP), uric acid(UA), and folic acid(FA) in solution. First, cyclic voltammetry was used to investigate the redox properties of the modified electrode at various scan rates. Next, the mediated oxidation of IP at the modified electrode is described. At the optimum pH of 7.0, the oxidation of IP occurs at a potential about 90 mV less than that of an unmodified carbon paste elec-trode. Based on the results of differential pulse voltammetry(DPV), the oxidation of IP showed a dynamic range between 10 and 6000 μmol/L, and a detection limit of 1.24 μmol/L. Finally, DPV was used to simultaneously determine the concentrations of IP, UA, and FA in solution at the modified electrode.     

石墨烯修饰玻碳电极测定邻苯二酚

制备了用于测定邻苯二酚(CAT)的石墨烯修饰电极,并应用循环伏安法研究了CAT在该修饰电极上的电化学行为;用差分脉冲伏安法研究了测试底液的pH值对该修饰电极性能的影响,结果表明,此修饰电极在含不同浓度CAT的PBS溶液(pH=7.0)中测定,响应电流与CAT浓度在5.0×10-8～5.6×10-4mol/L范围内有良好的线性关系,相关系数r=0.9919,检出限为6.68×10-9mol/L(S/N=3)。与其它几种修饰电极相比,石墨烯修饰电极制备简单、响应时间快、操作简便,稳定性和重现性良好,有应用价值。     

方波伏安法测定新型修饰多壁碳纳米管糊电极对肼的电催化氧化(英文)

The application of p-aminophenol as a suitable mediator, as a sensitive and selective voltammetric sensor for the determination of hydrazine using square wave voltammetric method were described. The modified multiwall carbon nanotubes paste electrode exhibited a good electrocatalytic activity for the oxidation of hydrazine at pH = 7.0. The catalytic oxidation peak currents showed a linear dependence of the peaks current to the hydrazine concentrations in the range of 0.5–175 μmol/L with a correlation coefficient of 0.9975. The detection limit (S/N = 3) was estimated to be 0.3 μmol/L of hydrazine. The relative standard deviations for 0.7 and 5.0 μmol/L hydrazine were 1.7 and 1.1%, respectively. The modified electrode showed good sensitivity and selectivity. The diffusion coefficient (D = 9.5 × 10–4 cm2/s) and the kinetic parameters such as the electron transfer coefficient (α = 0.7) of hydrazine at the surface of the modified electrode were determined using electrochemical approaches. The electrode was successfully applied for the determination of hydrazine in real samples with satisfactory results.     

双酚A在氮掺杂多壁碳纳米管修饰电极上的电化学行为及测定

构建了不同百分含量的氮掺杂的多壁碳纳米管化学修饰石墨电极,利用线性扫描伏安法及循环伏安法研究了双酚A(BPA)在修饰电极上的电化学行为。提出了一种灵敏、简便的直接检测双酚A的电化学分析方法。在pH6.98的PBS缓冲溶液中,在电位0.20 V富集后,该修饰电极在0.680 V出现一个灵敏的、峰形好的氧化峰。表明氮掺杂多壁碳纳米管薄膜对双酚A的氧化表现出一定的催化作用,能显著提高双酚A的氧化峰电流。在优化条件下,采用线性扫描伏安法对双酚A进行测定。双酚A的氧化峰电流与其浓度在2.5×10-7～1.0×10-4 mol/L之间有很好的线性关系(R为0.996),检出限为5.0×10-8mol/L。电极已初步用于实际样品中BPA的测定。     

聚铬黑T修饰电极检测亚硝酸盐的研究

利用电化学聚合法将铬黑T修饰到玻碳电极表面,制得聚铬黑T修饰电极。该修饰电极对亚硝酸盐的电化学氧化具有明显的催化作用,这种催化作用主要是由于聚铬黑T薄膜与带负电荷的亚硝酸盐离子的静电相互作用,导致亚硝酸盐离子富集在电极表面/溶液界面,显著增强了亚硝酸盐的氧化电流。电子传输系数α为0.735。选用0.85V作为工作电压,对亚硝酸盐进行安培检测,在0.05μmol/L～1.0 mmol/L和1.0～20.0 mmol/L两个浓度范围内呈现良好的线性关系,检测限达到0.01μmol/L。且该修饰电极有良好的重现性和稳定性。将该修饰电极用于泡菜中亚硝酸盐的测定,获得了满意的结果。     

尿酸和叶酸存在下改性碳纳米管糊电极上多巴胺电催化氧化MohammadMazloum-Ardakani,MahboobeAbolhasani,Bibi-FatemehMirjalili,MohammadAliSheikh-Mohseni,AfsanehDehghani-Firouzabadi,AlirezaKhoshroo简

A chemically modified carbon paste electrode (CPE), consisting of 2,2''-[(1E)-(1,2-phenylenebis(azanylylidene)] bis(methanylylidene)]bis(benzene-1,4-diol) (PBD) and multiwalled carbon nanotubes (CNTs), was used to study the electrocatalytic oxidation of dopamine using cyclic voltammetry, chronoamperometry, and differential pulse voltammetry (DPV). First, the electrochemical behavior of the modified electrode was investigated in buffer solution. Then the diffusion coefficient, electrocatalytic rate constant, and electron-transfer coefficient for dopamine oxidation at the surface of the PBD-modified CNT paste electrode were determined using electrochemical approaches. It was found that under optimum conditions (pH = 7.0), the oxidation of dopamine at the surface of such an electrode occurred at about 200 mV, lower than that of an unmodified CPE. DPV of dopamine at the modified electrode exhibited two linear dynamic ranges, with a detection limit of 1.0 μmol/L. Finally, DPV was used successfully for the simultaneous determination of dopamine, uric acid, and folic acid at the modified electrode, and detection limits of 1.0, 1.2, and 2.7 μmol/L were obtained for dopamine, uric acid, and folic acid, respectively. This method was also used for the determination of dopamine in a pharmaceutical preparation using the standard addition method.     

壳聚糖-铜复合物修饰电极对过氧化氢电催化性能的研究

将壳聚糖与铜盐通过配位结合制得壳聚糖-铜复合物(CTS-Cu),并用其修饰玻碳电极,使用循环伏安法和计时安培法研究了该修饰电极对H2O2的电催化性能,对其催化机理进行了探讨.优化的实验条件为:以0.1 mol/L.磷酸缓冲溶液(PBS,pH 7.0)为反应介质,CTS-Cu修饰液中的铜离子浓度为6 mmol/L,工作电...     

邻苯二酚和对苯二酚在钴氢氧化物膜修饰玻碳电极上的选择性测定

通过镀膜/循环伏安法制备了钴氢氧化物膜修饰的玻碳电极。该修饰电极对邻苯二酚(CA)和对苯二酚(HQ)具有较强的电催化活性。考察了支持电解质酸度对邻苯二酚和对苯二酚电化学响应的影响,选用0.1 mol/LPBS(pH 10.0)作为支持电解质。利用差示脉冲伏安法(DPV)对邻苯二酚和对苯二酚进行选择性检测,当两者浓度同时改变时,邻苯二酚和对苯二酚在6～100μmol/L范围内氧化峰电流与其浓度呈良好的线性关系,检出限分别为2×10–7,5×10–7mol/L(S/N=3)。钴氢氧化物膜电极具有较好的稳定性、重现性及较强的抗干扰能力,将此修饰电极应用于模拟水样中邻苯二酚和对苯二酚的测定,回收率为95.4%～100.4%。     

亚硝酸根在磷钼镍杂多酸-聚吡咯膜修饰电极上的伏安行为及其含量测定

研究了亚硝酸根(NO     

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.     

壳聚糖碳纳米管修饰电极测定痕量铜

建立了用自制的碳纳米管壳聚糖修饰电极测定Cu^2＋离子的电分析方法,在0．10mol／L的CH,COOH—CH3 COONa（pH4．2）缓冲溶液中,以此修饰电极作为工作电极,以-0．60V为富集电位,搅拌富集6min后,用差分脉冲伏安法测定-0．10V处的峰电流。结果发明,该电极对铜离子吸附的灵敏度较高,当铜离子浓度为1．0×10^-6～4．6×10^-5mol／L时,线性关系良好,相关系数为0．9997,对含铜血清样本进行测定,取得了满意的结果,加标回收率在98％～102％之间。     

以3,4-二羟基肉桂酸为介质的多壁碳纳米管糊电极用于检测药物和尿液样品中的谷胱甘肽(英文)

A sensitive and selective electrochemical sensor for the determination of glutathione(GSH) was developed using a modified multiwall carbon nanotube paste electrode with 3,4 dihydroxy cinnamic acid as a mediator.This modified electrode showed very high electrocatalytic activity for the anodic oxidation of GSH.Under the optimized conditions,the electrocatalytic peak current showed a linear relationship with GSH concentration in the range of 0.5-400.0 μmol/L with a detection limit of 0.1 μmol/L GSH.The relative standard deviations for seven successive assays of 5.0 and 25.0 μmol/L GSH were 2.2% and 2.7%,respectively.The modified electrode was used for the determination of GSH compounds in real urine samples.     

聚乙烯吡咯烷酮/硫化镉量子点修饰电极的制备及其对血红蛋白的测定研究

制备了聚乙烯吡咯烷酮(PVP)表面修饰的硫化镉(CdS)半导体纳米晶体(量子点), 并将其修饰玻碳电极, 用于血红蛋白(Hemoglobin, Hb)的电化学行为的研究. 实验结果表明, 血红蛋白在该修饰电极上有良好的电流响应, 流动注射分析结果进一步表明该修饰电极具有好的稳定性和重现性. 在1.0×10^－8～2.0×10^－5 mol/L浓度范围内, 血红蛋白的浓度与其响应电流呈良好的线性关系, 线性相关系数为0.9986, 检出限为5.0×10^－9 mol/L. 将该方法用于全血中血红蛋白的测定, 也获得了良好的结果.     

维生素B_6在纳米Au-N,P/石墨烯修饰电极上的电化学行为

将金纳米粒子(AuNPs)电沉积在N,P/石墨烯(N,P/Graphene)修饰的玻碳电极表面,研究了维生素B_6(VB_6)在该修饰电极上的电化学行为。实验结果表明:VB_6在该修饰电极上出现一个良好的氧化峰,在最佳实验条件下,其氧化峰电流与VB_6的浓度在2.0×10~(-5)~4.0×10~(-4) mol/L范围内呈线性关系,相关系数R=0.998,检出限为9.2×10~(-6) mol/L。一些常见的物质如K~+、Na~+、Zn~(2+)、葡萄糖(Glu)不干扰VB_6的检测。此方法已用于片剂中VB_6含量的检测,获得较好结果。     

介孔炭/纳米金修饰玻碳电极的制备及其应用研究

制备了介孔炭/纳米金修饰玻碳电极,并对对苯二酚(HQ)在该修饰电极上的电化学行为进行了研究。与HQ在纯介孔炭材料修饰玻碳电极上的电化学响应相比,HQ在该修饰电极上的氧化峰和还原峰电流均大大增加,表明纳米金与介孔炭复合后对HQ具有良好的催化作用。HQ在该修饰电极上经过富集后,峰电流明显增大。采用循环伏安法对HQ电化学行为进行研究,结果表明,HQ在3.0×10-8~1.0×10-6mol/L和1.0×10-6~1.0×10-4mol/L浓度范围内与峰电流呈良好的线性关系,据此建立了检测HQ的电化学分析方法。该方法的相对标准偏差为0.69%,检出限(S/N=3)为1.0×10-8mol/L,具有较高的稳定性和灵敏度。     

聚氨基黑10B/Nafion修饰电极上多巴胺的检测

用电化学聚合法制备了聚氨基黑10B/Nafion修饰电极,利用循环伏安法研究了多巴胺在此修饰电极上的电化学行为.在磷酸盐缓冲溶液(pH 6.0)中,多巴胺在修饰电极上呈现可逆的氧化还原峰.其峰电位都随pH值的增加而负移.多巴胺氧化还原峰电流与其浓度在0.2～30 μmol/L范围内呈良好的线性关系;检出限为1.0×10~7 mol/L.实验结果表明:本修饰电极具有良好的重现性、稳定性和较强的抗干扰能力.将此修饰电极用于多巴胺注射液和小牛血清中多巴胺的检测,结果令人满意.