柠檬酸修饰电极对抗坏血酸、多巴胺和尿酸的同时检测

研究柠檬酸(CA)修饰玻碳电极(CA/GC)在抗坏血酸(AA)、多巴胺(DA)和尿酸(UA)混合体系中的循环伏安(CV)行为.结果表明,AA、DA和UA在CA/GC电极上氧化峰电流增大,且三者氧化峰电位明显分离(ΔEp(DA,AA)=170 mV,ΔEp(DA,UA)=130 mV,ΔEp(AA,UA)=300 mV).据此,可同时检测AA、DA和UA.在优化的实验条件下,AA、DA和UA的氧化峰电流与其浓度分别在2.0×10-6～1.5×10-3mol.L-1,6.0×10-7～1.0×10-3mol.L-1和6.0×10-7～1.0×10-3mol.L-1范围内呈线性关系.该电极重现性好,可用于盐酸多巴胺针剂DA、VC片剂AA及人体尿液UA的测定.     

碳纳米管修饰电极对多巴胺和肾上腺素的电分离及同时测定

研究了多巴胺 (DA)和肾上腺素 (EP)在多壁碳纳米管 (MWNT)修饰电极上的电化学性质 ,发现该修饰电极对神经递质DA和EP有显著的增敏和电分离作用。还原峰电位差达ΔEp=390mV ,可同时测定DA和EP。DA和EP的还原峰电流与其浓度分别在 2 .0× 10 -6～ 1.0× 10 -3 mol/L和 1.0× 10 -6～ 1.0× 10 -3 mol/L浓度范围内呈良好的线性关系 ;方法的检出限分别为 1× 10 -6mol/L和 5× 10 -7mol/L。由于抗坏血酸 (AA)在MWNT修饰电极上的氧化是不可逆的 ,因此利用还原峰进行测定 ,消除了AA对DA和EP的干扰     

肉桂酸修饰电极同时测定多巴胺和抗坏血酸的研究

用电化学聚合方法制备肉桂酸(CA)修饰的玻碳电极(PCA/GC),研究多巴胺(DA)和抗坏血酸(AA)在修饰电极上的电化学行为.结果表明,在DA和AA共存体系中,DA、AA在PCA/GC电极上氧化峰电流增大且氧化峰电位相差200 mV,据此可同时检测DA和AA.在pH 7.0磷酸盐缓冲液中,DA和AA的氧化峰电流与其浓...     

2,3-二巯基丁二酸修饰金电极伏安法同时测定肾上腺素及多巴胺

研究结果表明:肾上腺素(EP)及多巴胺(DA)在2,3-二巯基丁二酸修饰金电极上的电化学响应,由于该修饰电极的催化作用而明显增强。在pH6.7的磷酸盐缓冲溶液中,肾上腺素及多巴胺的氧化峰电流(ipc)值依次为0.793,1.059μA,多巴胺的还原峰电流(ipa)为1.249μA,肾上腺素在此条件下无还原峰。在肾上腺素及多巴胺共存的溶液中,还原峰电流只与多巴胺的存在有关,而氧化峰电流值恰为两者氧化峰电流值之和。多巴胺浓度在4.0×10-6～1.0×10-4mol.L-1范围内与相应的ipa值之间呈线性关系,而肾上腺素浓度在1.0×10-5～1.0×10-4mol.L-1之间与相应的ipc值之间呈线性关系。据此提出了同时测定肾上腺素及多巴胺的伏安法。此方法对肾上腺素及多巴胺的测定结果分别在0.98～1.03 g.L-1和0.97～1.02 g.L-1之间。     

PCA/GC电极同时测定尿酸(UA)和抗坏血酸(AA)

制备聚肉桂酸(PCA)修饰电极(PCA/GC),研究尿酸(UA)和抗坏血酸(AA)在该电极上的电化学行为.结果表明,在UA和AA共存体系中,UA、AA在PCA/GC电极上氧化峰电流增大且峰电位分别负移至50mV、330mV,二者相差280mV,据此可同时检测UA和AA.在pH6.0磷酸盐缓冲液中,UA、AA的氧化峰电流与其浓度分别在2.0×10-6～1.0×10-4mol·L-1、2.0×10-5～6.0×10-4mol·L-1范围内呈线性关系.该电极重现性好,适用于尿样中UA的检测.     

镍纳米粒子-离子液体修饰碳糊电极的制备及其对多巴胺的测定

制备了镍纳米粒子-离子液体修饰电极,在0.1 mol/L磷酸缓冲溶液(pH 6.0)中研究了多巴胺(DA)在修饰电极上的电化学行为.与裸电极相比,DA在该修饰电极上的氧化还原电位明显降低,氧化还原反应的峰电流明显增大,DA的峰电流与其浓度在2.0×10~(-8) ～1.0×10~(-4) mol/L范围内呈良好的线性关系,检出限为6.5×10~(-9) mol/L.该修饰电极对抗坏血酸具有明显的抗干扰能力.     

聚L-谷氨酸/石墨充蜡修饰电极测定多巴胺

用充蜡石墨电极 (WGE)在L 谷氨酸 (GA)无水乙醇溶液中恒电位于 1.6V(vs.SCE)氧化制备了一种聚GA修饰电极 (GA/WGE) ,该电极可用于肾上腺素 (EP)和抗坏血酸 (AA)共存下对多巴胺 (DA)的测定。该电极的灵敏度和选择性主要取决于阳极极化电位与极化时间、富集电位和溶液的pH。DA在该电极上呈现一对循环伏安峰 ,Em=0 .14 5V ,为 1电子 / 1质子的准可逆氧化还原过程。AA和EP也能够在电极上富集和催化氧化 ,伏安峰分别在 0 .30V和 0 .17V。当AA浓度小于 0 .1mmol/L时 ,电极对AA基本不响应 ,可以用DA的氧化峰电流做定量分析。线性范围为 2 .0× 10 -4～ 5 .0× 10 -7mol/L ;检出限为 2 .5× 10 -7mol/L。当AA的浓度较大或在AA、EP共存下 ,可利用DA氧化的再还原峰电流做定量分析。线性范围为 1.0× 10 -4～ 2 .5× 10 -6mol/L ;检出限为 7.5× 10 -7mol/L。该电极制作简便 ,重现性良好 ,定量结果也令人满意     

聚L-白氨酸修饰电极伏安法测定痕量多巴胺的研究

用循环伏安法制备了聚L-白氨酸修饰玻碳电极,研究了多巴胺在聚L-白氨酸修饰玻碳电极上的电化学行为,建立了循环伏安法测定痕量多巴胺的新方法。实验结果表明,在pH 6.0的磷酸盐缓冲溶液中,多巴胺在聚L-白氨酸修饰玻碳电极上产生一对灵敏的氧化还原峰,峰电位分别为Epa=0.281V,Epc=0.170 V(相对Ag/AgCl电极)。峰电流与多巴胺的浓度在5.0×10-8~5.0×10-4mol/L的范围内有线性关系,检出限为5.0×10-9mol/L。对1.0×10-5mol/L多巴胺溶液平行测定9次,其相对标准偏差为4.0%。已用于针剂中多巴胺的测定。     

氮掺杂碳纳米管修饰电极的电化学行为

制备了氮掺杂改性的碳纳米管, 并用循环伏安法(CV)测定了多巴胺(DA)和抗坏血酸(AA)在不同氮含量的碳纳米管修饰电极上的电化学行为. 结果表明, 氮掺杂碳纳米管修饰电极对AA和DA有不同的电催化行为, 其中高氮含量修饰电极对AA的催化作用强, 而低氮含量修饰电极对DA的催化作用强. 微分脉冲伏安法(DPV)的结果显示, DA的氧化峰电流与其浓度在5.0×10^－6～2.0×10^－4 mol/L范围内呈良好的线性关系, 检出限达1.64×10^－6 mol/L (S/N＝3); AA氧化峰电流与其浓度在3.0×10^－5～1.0×10^－2 mol/L范围内呈良好的线性关系, 检出限达3.26×10^－6 mol/L (S/N＝3). 该修饰电极在AA大量存在(AA浓度为DA浓度两万倍)时可选择性地实现多巴胺的测定而不造成干扰.     

纳米金双巯基修饰金电极差分脉冲伏安法测定多巴胺和抗坏血酸

在裸金电极上自组装4,4-二甲基联苯硫醇(MTP)膜(MTP/AuSAMs),再电还原氯金酸溶液修饰纳米金,得纳米金双巯基修饰金电极(NG/MTP/Au).研究了多巴胺(DA)和抗坏血酸(AA)在NG/MTP/Au上的电化学行为,发现该修饰电极对DA、AA的氧化具有良好的电催化作用,多巴胺(DA)和抗坏血酸(AA)的氧化峰电位差达到155mV,可以实现对此二组分混合溶液的选择性测定.差分脉冲法测得的峰电流与DA、AA浓度分别在5.0×10-7～1×10-4mol.L-1和3.5×10-6～1.0×10-3mol.L-1范围内呈线性关系,检测限(3σ)分别为1.5×10-7mol.L-1和1.2×10-6mol.L-1,相关系数0.998.     

银掺杂聚L-酪氨酸修饰电极同时测定多巴胺、肾上腺素和抗坏血酸

用循环伏安法制备银掺杂聚L-酪氨酸修饰玻碳电极,研究了多巴胺、肾上腺素和抗坏血酸在其电极上的电化学行为,建立了同时测定多巴胺、肾上腺素和抗坏血酸的新方法。当3种组分共存时,在磷酸盐缓冲溶液(pH6.0)中,扫描速率为140mV/s,多巴胺和肾上腺素在修饰电极上分别产生还原峰,峰电位分别为0.198和-0.205V,多巴胺和肾上腺素氧化峰重叠,峰电位为0.313V(vs.Ag/AgCl);抗坏血酸产生一个氧化峰,峰电位0.108V(vs.Ag/AgCl)。多巴胺和肾上腺素的ΔEpc=0.403V,抗坏血酸的氧化峰与多巴胺和肾上腺素的ΔEpa=0.205V,用还原峰和氧化峰可同时测定多巴胺、肾上腺素和抗坏血酸,3种组分同时测定的线性范围分别为5.0×10-6～1.0×10-4mol/L,8.0×10-6～1.0×10-4mol/L和3.0×10-5～1.0×10-3mol/L;检出限分别为5.0×10-7,8.0×10-7和5.0×10-6mol/L。本方法用于人尿液中多巴胺、肾上腺素和抗坏血酸的同时测定,结果满意。     

Caffeic Acid‐Modified Glassy Carbon Electrode for the Simultaneous Determination of Epinephrine and Dopamine

A stable electroactive thin film of poly(caffeic acid) has been deposited on the surface of a glassy carbon electrode by potentiostatic technique in an aqueous solution containing caffeic acid. The electrochemical behaviors of epinephrine (EP), dopamine (DA) and their mixture have been studied. The oxidation peaks of EP and DA at the poly(caffeic acid) modified glassy carbon electrode appeared at the same potential, but the anodic peak currents of the mixture of DA and EP were almost equal to the sum of individual anodic peak currents of EP and DA, whereas the cathodic peak current only related to the concentration of DA under appropriate condition. Base on these, the simultaneous voltammetric measurement of EP and DA at the poly(caffeic acid) film modified electrode has been developed. Ascorbic acid (AA) had no interference with the simultaneous determination of EP and DA under the same condition because the oxidative peak potential of AA was less than those of DA and EP. The modified electrode has been satisfactorily used for the simultaneous determination of EP and DA in real samples.     

A novel poly(taurine) modified glassy carbon electrode for the simultaneous determination of epinephrine and dopamine

A novel taurine modified glassy carbon electrode was prepared by electropolymerization method. The electrochemical behaviors of epinephrine (EP) and dopamine (DA) at the modified electrode were studied by cyclic voltammetry. The modified electrode exhibited enhanced sensitivity and excellent electrochemical discrimination to DA and EP. The cathodic peaks of the two species were well-separated with a potential difference of about 390 mV, so the poly(taurine) modified electrode was used for simultaneous voltammetric measurement of EP and DA by differential pulse voltammetry. Under the optimum conditions, the cathodic peak currents were linear to concentrations of EP and DA in the range of 2.0 × 10⁻⁶ to 6.0 × 10⁻⁴ mol L⁻¹ and 1.0 × 10⁻⁶ to 8.0 × 10⁻⁴ mol L⁻¹, respectively. The detection limits for EP and DA were 3.0 × 10⁻⁷ and 1.0 × 10⁻⁷ mol L⁻¹, respectively. Because the oxidation of ascorbic acid (AA) is an irreversible reaction at modified electrode, the interference of AA for determining EP and DA was eliminated. The modified electrode has been satisfactorily used for the simultaneous determination of EP and DA in pharmaceutical injections.     

用修饰电极导数伏安法同时测定多巴胺和肾上腺素

研究了２,６－吡啶二甲酸在玻碳电极上电化学聚合的实验条件及修饰电极的电化学特性,发现该聚合物膜修饰电极对多巴胺和肾上腺素的电化学氧化有显著的催化作用,而对抗坏血酸等阴离子没有响应。利用在修饰电极上循环伏安阴极过程多巴胺和肾上腺素的峰电位不同,采用阴极化导数伏安法可同时测定多巴胺和肾上腺素。     

2,3-Dimercaptosuccinic acid self-assembled gold electrode for the simultaneous determination of epinephrine and dopamine

Simultaneous determination of epinephrine(EP)and dopamine(DA)at 2,3-dimercaptosuccinic acid(DMSA)modified electrode was studied.The oxidation peaks of the mixture of EP and DA appeared at the same potential,but the cathodic peak currents were only linear to the concentration of DA,whereas the anodic peak currents were equal to the sum of individual anodic peak currents of EP and DA.Therefore,a novel electrochemical method for the simultaneous determination of EP and DA at a DMSA modified electrode(DMSA/A...     

聚L-苏氨酸修饰电极对多巴胺和肾上腺素的电催化氧化

利用循环伏安法将L-苏氨酸聚合修饰在玻碳电极表面, 制成聚L-苏氨酸修饰电极. 实验表明, 该电极对多巴胺和肾上腺素都有较好的催化氧化效果. 运用循环伏安法详细研究了修饰电极的电化学性质. 在pH 2.5的磷酸盐缓冲溶液(PBS)中, 肾上腺素的电子传递系数为0.51, 表观反应速率常数为1.33 s-1; 在pH 7.5的PBS中, 多巴胺在电极上产生一对氧化还原峰, 多巴胺在电极上的电子传递系数为0.60, 表观反应速率常数为0.92 s-1. 该修饰电极对多巴胺和肾上腺素能够进行同时测定, 还原峰电流与多巴胺和肾上腺素浓度分别在1.0×10-6-5.0×10-4 mol·L-1和3.0×10-6-1.0×10-4 mol·L-1范围内呈现良好的线性关系.     

Electroanalysis and simultaneous determination of dopamine and epinephrine at poly(isonicotinic acid)-modified carbon paste electrode in the presence of ascorbic acid

A carbon paste electrode modified with electropolymerized fills of isonicotinic acid was developed.The modified electrode shows excellent electrocatalytic activity toward the oxidation of both dopamine(DA)and epinephrine(EP).Separation of the reduction peak potentials for dopamine and epinephrine was about 357 mV in pH 5.3 phosphate buffer solution(PBS)and the character was used for the detection DA and EP simultaneously.The peak currents increase linearly with DA and EP concentration over the range of 8.0×10-5 to 7.0×10-4 mol/L and 5.0×10-6 to 1.0×10-4 mol/L with detection limits of 2 × 10-5 and 1×10-6 mol/L,respectively.The interference studies showed that the modified electrode exhibits excellent selectivity in the presence of large excess of ascorbic acid(AA).     

α-环糊精包结碳纳米管涂层电极同时测定多巴胺和肾上腺素

本文发现α-环糊精包结碳纳米管涂层电极对多巴胺（DA）和肾上腺素（EP）具有显著的增敏和电分离作用，还原峰电位差达390 mV。研究表明α-环糊精包结碳纳米管涂层薄膜表现出了非常令人感兴趣的电催化特性。因抗坏血酸（AA）在α-环糊精包结碳纳米管涂层电极上的氧化是不可逆的，因此利用还原峰进行测定，消除了AA对DA和EP的干扰。由于成本低和制作简便，该电极可用于生物系统电化学研究的生物传感器。     

Simultaneous determination of dopamine and ascorbic acid at a poly(toluidine blue) modified electrode.

A novel polymer modified electrode is discussed in this paper. This resulting electrode can catalyze remarkably toward the electrochemical oxidations of dopamine (DA) and ascorbic acid (AA). Moreover, it can clearly discriminate the electrochemical oxidations of DA from that of AA based on their semi-derivative voltammograms. Hence, a simultaneous determination of DA and AA based on semi-derivative voltammetry at a poly(toluidine blue) modified electrode is suggested. The detection linear range for DA is 0.4 micromol L(-1)-1.5 mmol L(-1), and AA 0.2 micromol L(-1)-2.4 mmol L(-1), respectively. The resulting modified electrode was tentatively used to determine DA and AA in brain tissue.