药物分子在玻碳电极电的电分析化学研究：Ⅳ.乙酰螺旋霉素的伏安测定

本文对乙酰螺旋霉素在ＧＣＥ上的伏安行为进行了研究，发现在磷酸盐缓冲溶液（ｐＨ＝７．７８）中，於＋０．８５Ｖ（ｖｓ，Ａｇ／ＡｇＣｌ）左右产生一良好的阳极氧化伏安峰，浓度在０．５～１００μｇ／ｍＬ之间与峰电流呈线性关系，分析了制剂中乙酰螺旋霉素的含量，相对标准偏差为４．５％，平均回收率为１０１％，经循环伏安法验证，电极反应为不可逆反应。     

药物分子在玻碳电极上的电分析化学研究──Ⅴ．安乃近的伏安行为及测定

提出了一种测定安乃近新法。由于安乃近没有电活性，故将安乃近和盐酸在１００℃共热后生成电活性产物，用玻碳电极在０．１ｍｏｌ／ＬＮａＯＨ中得一良好的阳极氧化伏安峰，Ｅｐ＋０．３５Ｖ（ｖｓ·Ａｇ／ＡｇＣｌ）左右，峰电流与安乃近浓度在０．１～１００ｍｇ／Ｌ之间呈线性关系，分析了制剂安乃近的含量，实验证实电极反应属于扩散控制的不可逆过程。     

药物分子在玻碳电极上的电分析化学研究

提出了一种测定安乃近新法。由于安乃近没有电活性，故将安乃近和盐酸在１００℃共热后生成电活性产物，用玻碳电极在０．１ｍｏｌ／Ｌ ＮａＯＨ中得一良好和阳极氧化伏安峰，Ｅｐ＋０．３５Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）左右，峰电流与安乃近浓度在０．１－１００ｍｇ／Ｌ之间呈线性关系，分析了制剂安乃近的含量，实验证实电极反应属于扩散控制的不可逆过程。     

麦地霉素在玻碳电极上的阳极伏安法研究

用线性扫描伏安法（ＩＳＶ）、微分脉冲伏安法（ＤＰＶ）和循环伏安法（ＣＶ）在玻碳电极 （ＧＣＥ）上研究了麦地霉素（ＭＤ）在不同介质中的阳极伏安行为。发现在０．１ｍｏｌ／Ｌ Ｎａ_２ＨＰＯ_４溶 液中于０．７５Ｖ（υｓ． Ａｇ／ＡｇＣｌ）左右产生一个阳极氧化峰,峰高与ＭＤ浓度５ × １０~（－５）～１×１０~－１ｇ／Ｌ 范围内呈线性关系。用本法不需分离直接测定了药物制剂和加标尿样。ＲＳＤ为１．８％（ｎ＝ １０）。尿样中ＭＤ的回收率为９５％～１１５％。实验结果表明ＭＤ的电极氧化反应为不可逆过 程。     

多组分有机物在玻碳电极上的伏安法测定

对乙酰氨基苯乙醚,氨基比林,乙酰氨基苯酚,氨基苯酚等４种有机物在玻碳电极上的伏安行为进行了研究。在０．１ｍｏｌ／Ｌ氢氧化钠溶液中得到４个灵敏度和分辨率良好的阳极氧化峰。Ｅｐ分别为０．６８,０．５１,０．２２－０．０６Ｖ（ｖｓ．ＡｇＣｌ／Ａｇ）左右,样品不需分离直接测定。     

罂粟碱的吸附伏安行为的研究

在ＮＨ３－ＮＨ４Ｃｌ底液中，罂粟碱在汞电极上有一一线性扫描还原峰，峰电位Ｅｐｃ＝－１．４４（ｖｓ．ｓａｔ．Ａｇ／ＡｇＣｌ）。该峰具有明显的吸附性。当ＰＡＰ浓度较小时，扫速较快，搅拌富集时间较长时，电极反应完全为吸附态的ＰＡＰ的还原所控制。     

苯胺在碱性溶液中的电化学聚合和聚合物的性质

苯胺在碱性溶液中电化学氧化时，阳极上形成深黄色的聚苯胺，其氧化峰电位为０．７Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ含饱和ＫＣｌ溶液），比在酸性溶液中氧化约低０．３Ｖ，环一盘电极实验结果表明，在碱性溶液中，苯胺氧化时生成两种可溶性的中间物，形成的聚合物颜色不随电位和ｐＨ值而变化，在空气和碱性溶液中具有很高的稳定性，在紫外－可见光谱图上，聚合物的吸收峰出现在５００ｍ左右。     

氯氮平的吸附伏安行为

在０．１ｍｏｌ／ＬＮＨ４Ａｃ（ｐＨ７．８）底液中，氯氮平（ＣＬＰ）在汞电极上有一线性扫描还原峰，Ｅｐｃ＝－１．３４Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）．该峰具有明显的吸附性，吸附粒子为ＣＬＰ中性分子．测得ＣＬＰ在汞电极上的饱和吸附量为２．７×１０－１０ｍｏｌ／ｃｍ２，每个ＣＬＰ分子所占电极面积为０．６２ｎｍ２，ＣＬＰ在悬汞电极上的吸附符合Ｆｒｕｍｋｉｎ等温式．测得吸附系数β＝６．２８×１０５，吸引因素γ＝０．７５，电子转移数ｎ为２，不可逆吸附的转移系数α为０．５３．探讨了ＣＬＰ在汞电极上的还原机理，并建立了吸附溶出伏安法测定ＣＬＰ的最佳条件，检测限为８．０×１０－９ｍｏｌ／Ｌ．     

钪－间氯偶氮安替比林络合物吸附波的研究

在ｐＨ４．３０的ＨＡｃ－ＮａＡｃ介质中，钪－间氯偶氮安替比林（ｍ－ＣＡＡ）－硫氰酸钾生成三元络合物，于－０．３５Ｖ（ｖｓ．ＳＣＥ）处出现一尖锐的极谱峰，峰电流与钪离子浓度在０．０２０～０．２０μｇ／ｍＬ范围内呈线性关系，检出限为０．０１０μｇ／ｍＬ．用多种电化学方法研究了极谱波的性质及电极反应机理．方法用于矿样中钪的测定，结果满意     

脱乙酰壳多糖化学修饰电极测定铂的研究

用脱乙酰壳多糖修饰电极为工作电极，阳极溶出伏安法测定痕量铂。在ｐＨ＝２￣３的ＫＣｌ－ＨＣｌ底液中，－０．３Ｖ富集２ｍｉｎ，静止１５ｓ，以０．２Ｖ／ｓ扫速阳极溶出，峰电位在－０．１６Ｖ（ｖｓ．ＳＣＥ），铂（Ⅳ）离子浓度在０．５￣５．０μｇ／ｍＬ范围内与峰高呈线性关系。富集１０ｍｉｎ后，可检测０．０２５μｇ／ｍＬ铂（Ⅳ）。该法用于贵金属矿样的测定，无需分离，结果满意。用循环伏安法、紫外光谱和拉曼光谱研     

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...     

Voltammetric and amperometric determination of uric acid at a carbon-ceramic electrode modified with multi walled carbon nanotubes

The voltammetric behavior of uric acid (UA) was studied at a carbon-ceramic electrode modified with multi walled carbon nanotubes; which was developed via a simple procedure. UA can be effectively oxidized at the surface of the electrode and produced an anodic peak at about 0.29 V in pH 6.8 phosphate buffer solutions. The experimental parameters such as pH, accumulation time, and amount of multi walled carbon nanotubes were optimized for determination of UA. Under the optimum conditions, the anodic peak current in differential pulse voltammetry is linear to the UA concentration over the range from 2.5×10?7M to 1.0×10?4 M with a correlation coefficient of 0.998. The electrode exhibited good stability and could be easily regenerated. The relative standard deviation of the peak current obtained for a 5.0?×?10^?5 M UA solution was 1.0%. The influence of dopamine and ascorbic acid on the anodic peak current of UA was examined. This method was successfully applied for the determination of uric acid in human urine sample, and the recovery was 99.9%.     

预镀铋膜阳极溶出伏安法测定废水中微量铅和镉

本文采用预镀铋膜法修饰玻碳电极,并用该电极对废水中微量铅和镉同时进行了阳极溶出伏安法测定,研究了预镀铋膜测定铅和镉的条件。实验结果表明:铅和镉在铋膜电极上可得到灵敏的电位溶出峰,峰高和溶出电位与汞膜电极法相近,使用预镀铋膜电极可避免使用汞电极带来的环境污染。     

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。     

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.     

Subspeciation of nickel disulfide by carbon paste electrode voltammetry catalyzed by Ni2+

In subspeciation of sulfidic nickel, carbon paste electrode voltammetry was developed for the specific determination of Ni3S2 or NiS, but NiS2 was found to be unreactive. Ni2+ in pH 7.2 acetate solution was able to catalyze NiS2 to undergo redox reactions. The cyclic voltammogram showed two anodic peaks at -0.3 and +0.7 V and a cathodic peak at -0.6 V. The first anodic peak at -0.3 V and the cathodic peak were common among the three nickel sulfides, but the second anodic peak at +0.7 V was unique to NiS2. This peak current gave a linear dose response to NiS2 from 40 to 610 microg, with a correlation coefficient of 0.994, and a detection limit of 40 microg.     

Electrochemical Behavior and Determination of Uric Acid at Single-Walled Carbon Nanotube Modified Gold Electrodes

The voltammetric behavior of uric acid was studied at a single-walled carbon nanotube (SWNT) modified gold electrode. Uric acid can effectively accumulate at this electrode and produce an anodic peak at about 0.45 V (vs. SCE) in pH 5.0 sodium acetate buffer solutions (HAc-NaAc). The experimental parameters, such as solution pH, accumulation time, and amount of SWNT, were optimized for determination. Under the optimum conditions, the anodic peak current is linear to the uric acid concentration over the range of 1.0×10⁻⁷ M to 2.5×10⁻⁵ M with a correlation coefficient of 0.998. The detection limit was 5.0×10⁻⁸ M for 60 s accumulation. The electrode could be easily regenerated and exhibited good stability. A 5.0×10⁻⁶ M uric acid solution was measured ten times using the same electrode, and the relative standard deviation of the peak current was 1.3%. This method was successfully applied to the determination of uric acid in human urine samples, and the recovery was 97–99%. The feasibility for simultaneous determination of xanthine, ascorbic acid and uric acid was discussed. These species did not interfere with each other in a certain concentration range. The influence of some surfactants on the anodic peak was also examined.     

Determination of traces of metals by anodic stripping voltammetry at a rotating glassy carbon ring—disc electrode: Part 1. Method and instrumentation with evaluation of some parameters

The equipment and procedure are described for the determination without preconcentration of several heavy metals based on d.c. anodic stripping voltammetry at a rotating ring—disc glassy carbon electrode with in situ mercury plating. During stripping of the metals deposited on the disc, the current from the reduction of the ions collected at the ring is measured. Some parameters (scan rate, thickness of the mercury film, electrode rotation and deposition time) influencing the ring collection peak current are examined experimentally. The results are compared with the theoretical considerations given by de Vries and van Dalen for anodic stripping voltammetry on a stationary mercury film electrode and by Bakanov et al. for a rotating mercury film electrode.     

Direct electron transfer and voltammetric determination of roxithromycin at a single-wall carbon nanotube coated glassy carbon electrode

The electrochemical behavior of roxithromycin (RM) at a single-wall carbon nanotube (SWNT) coated glassy carbon (GC) electrode was studied. It was found that RM could produce an irreversible anodic peak at the electrode. When the pH of supporting electrolyte (i.e. phosphate buffer solution) was 7 the peak potential was 0.86V (vs. SCE). The electrochemical reaction contained electron and proton transfer, and the electron-transfer coefficient (α) was ca. 0.87. The anodic peak depended on the adsorption of RM, the maximum adsorption amount was about 3.99×10(-10)molcm(-2). The adsorbed RM could be removed by cycling between 0.1 and 1.1V in a blank solution for about two minutes, and the electrode thus could be regenerated. Under the optional conditions, the anodic peak current was linear to RM concentration over the range of 5.0×10(-6) to 1.0×10(-4)M. The limit of detection was 5.0×10(-7)M (S/N=3) for 180s accumulation at -0.8V. The modified electrode had good stability and repeatability, and it was successfully applied to the determination of RM in medicine samples.     

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.