电位型聚吡咯pH传感器的制备

电位型聚吡咯pH传感器的制备;聚吡咯; pH传感器; 电化学聚合; 交流阻抗     

Coupled Redox and pH Potentiometric Responses of Electrodes Coated with Polypyrrole

ABSTRACT

The coupled influence of solution acidity and redox electrolytes on the open-circuit potentials of polypyrrole-modified electrodes was studied by recording the potential vs. time dependencies. It was observed that doping anions affect the relative rate of the responses resulting from pH influence (pH response) and from the presence of a redox couple in the solution, such as Fe(III)/Fe(II) or Fe(CN)6^3-/4-(redox response). Separation of the pH and redox responses was possible for polypyrrole doped with large organic anions of weak acids (Tiron, sulphosalicylic acid, Indigo Carmine). In such cases, a very fast pH response was recorded after which the polymer potential relaxed to the solution redox potential in each case. The final stable potential was determined entirely by the potential of the redox couple in solution. The final potential was pH-independent unless the redox potential was influenced by solution acidity. The solution pH determines only the shape of the potential vs. the time dependence, e.g. much faster responses were observed for solutions with a higher H* concentration.     

聚合溶液pH值对染料敏化太阳电池中聚吡咯对电极结构和性能的影响

电化学合成聚吡咯（PPy）时,聚合电解液的pH 值对PPy 薄膜的形貌和性质有较大的影响,进而影响PPy薄膜对I^-/I₃^-的电催化活性以及基于PPy对电极（CE）的染料敏化太阳电池（DSSCs）的光电转换性能. 本文采用电化学恒电位方法,在掺杂氟的SnO₂（FTO）导电玻璃上合成出了对甲苯磺酸根离子掺杂的聚吡咯（PPy-TsO）电极,并将其作为DSSCs 的对电极. 通过改变吡咯聚合时聚合电解液的pH值,借助扫描电镜（SEM）、紫外-可见（UV-Vis）吸收光谱、X-射线光电子能谱（XPS）和循环伏安（CV）等表征技术,详细探讨了聚合溶液pH值对PPy CE形貌、结构及其对I^-/I₃^-的电催化性能的影响. 研究发现在pH 2.0下合成的聚吡咯对阴离子掺杂率最高且链共轭性最佳,具有对I^-/I₃^-氧化还原介质最强的催化能力,基于此PPy CE的电池光电转化效率也最高.pH 值太大或太小都不利于生成具有高掺杂率和高催化活性的PPy电极,组装成DSSCs后的光电转换效率也较低.     

聚合溶液pH值对染料敏化太阳电池中聚吡咯对电极结构和性能的影响

电化学合成聚吡咯(PPy)时,聚合电解液的pH值对PPy薄膜的形貌和性质有较大的影响,进而影响PPy薄膜对I-/I3-的电催化活性以及基于PPy对电极(CE)的染料敏化太阳电池(DSSCs)的光电转换性能.本文采用电化学恒电位方法,在掺杂氟的SnO2(FTO)导电玻璃上合成出了对甲苯磺酸根离子掺杂的聚吡咯(PPyTsO)电极,并将其作为DSSCs的对电极.通过改变吡咯聚合时聚合电解液的pH值,借助扫描电镜(SEM)、紫外-可见(UV-Vis)吸收光谱、X-射线光电子能谱(XPS)和循环伏安(CV)等表征技术,详细探讨了聚合溶液pH值对PPy CE形貌、结构及其对I-/I3-的电催化性能的影响.研究发现在pH 2.0下合成的聚吡咯对阴离子掺杂率最高且链共轭性最佳,具有对I-/I3-氧化还原介质最强的催化能力,基于此PPy CE的电池光电转化效率也最高.pH值太大或太小都不利于生成具有高掺杂率和高催化活性的PPy电极,组装成DSSCs后的光电转换效率也较低.     

复阻抗法分析聚吡咯材料的湿敏特性

通过延长聚合时间到96 h合成了一种对湿度敏感的聚吡咯材料. 采用红外(IR)光谱, X射线衍射(XRD)和扫描电子显微镜(SEM)的方法对合成的材料进行了表征. 测量了基于该材料的湿敏元件的湿度特性, 并且得到了在20 Hz-100 kHz频率范围内的复阻抗谱图. 基于测量结果讨论了该材料制备的湿敏元件的湿度敏感机制. 通过对复阻抗谱的分析研究了该湿敏元件的工作机理并且分析了参与导电的粒子.     

A Potentiometric Method for Determination of Oxidized Ketone Bodies in Milk

Following the decarboxylation of acetoacetic acid by heating and the separation of acetone from milk matrix by steam distillation, acetone was allowed to react with bromine in the presence of nitric acid, causing the formation of bromoacetone and bromide; the latter was then quantified by means of a suitable ion-selective electrode applying the calibration principle. Based on checking reproducibility and on comparative analyses performed by a widely accepted photometric method, the potentiometric method developed was found to be adequate for the determination of the oxidized ketone bodies.     

基于碳纳米管修饰电极/鸟嘌呤电化学体系的固体电位型pH传感器

根据鸟嘌呤在短单壁碳纳米管修饰玻碳电极(S-SWCNT/GCE)上发生的电催化氧化特性,及其氧化电位对支持电解质溶液的pH值具有灵敏的响应,制备了以鸟嘌呤为指示剂的固体电位型pH传感器。在优化各种影响因素后,其电位在pH2.0~12.0范围内具有线性响应,回归方程为Epa(V)=-0.0497pH 0.8931。该传感器制备简单,使用方便,响应时间<20 s。在pH响应范围内待测液中离子强度对测定没有影响。酸碱滴定终点具有明显的突跃。对Na 、K 和Ca2 的选择性系数小。已成功地应用于实际样品的测定。     

Potentiometric Membrane Sensor for Determination of Saccharin

A potentiometric poly(vinyl chloride) membrane sensor for determination of saccharin is described. It is based on the use of Aliquat 336S-saccharinateion-pair as an electroactive material in plasticized PVC membranes with o-nitrophenyloctylether or dioctylphthalate. The sensor is conditioned for at least two days in 0.1 mol L⁻¹ sodium saccharinate before use. It exhibits fast, stable and Nernstian response for saccharinate ions over the concentration range of 1.0 × 10⁻¹–5.0 × 10⁻⁵ mol L⁻¹ and pH range of 4.5–11. The sensor is used for determination of saccharin in some dosage forms. Results with an average recovery of 101% and a mean standard deviation of 0.2% are obtained which is compared favourably with data obtained using the British pharmacopoeia method. The sensor shows reasonable selectivity towards saccharin in presence of many anions and natural sweeteners.     

功能聚吡咯膜修饰电极的制备及其应用

本文对功能聚吡咯膜修饰电极的制备及其在电化学催化、电化学释放、分子器件、电变色效应、生物传感器以及电化学分析等方面的应用进行了综述,引参考文献五十篇。     

基于LabVIEW 8.0的pH电位滴定虚拟仪器

运用离子选择性电极、调理电路、DAQ卡和计算机,构建了基于LabVIEW 8.0的电位滴定虚拟仪器,实现了电位滴定实验数据的自动记录和自动处理.将该虚拟仪器应用到乙酸等的电位滴定实验表明,实验结果相对标准偏差小于0.65%,提高了实验结果的重现性和准确性;且虚拟仪器界面友好、操作简便、实时绘出滴定曲线,自动处理数据及即时得到结果.     

有机溶液中添加水对聚吡咯电化学性能的影响

采用电势阶跃技术, 于Pt微盘电极上在含水体积分数分别为0, 2%, 4%, 6%和8%的0.1 mol/L Pyrrole+0.1 mol/L LiClO₄的碳酸丙烯酯(PC)溶液中合成了聚吡咯(PPy)膜. 采用循环伏安法、计时电流法考察了不同含水比例条件下聚吡咯的电化学行为, 采用扫描电镜对其表面形貌进行了观察分析. 研究结果表明, 最佳的含水体积分数为6%. 在此条件下聚合得到的PPy量大, 具有较高的电化学容量、较好的电化学反应可逆性.     

Fabrication of a Single Layer and Bilayer Potentiometric Biosensors for Penicillin by Galvanostatic Entrapment of Penicillinase into Polypyrrole Films

A single layer and bilayer potentiometric biosensors for the detection of penicillin have been developed. The favourable conditions that were established for the polypyrrole‐penicillinase ((PPy‐P’nase) single layer biosensor were 0.03 M pyrrole, 50 U/mL P’nase, 0.01 M penicillin, applied current density of 0.9 mA/cm² and a polymerisation time of 40 s. The optimum conditions for the formation of the outer layer of the bilayer were: (a) 0.1 M Py, 19 U/mL P’nase, 0.01 M pen, current density of 0.9 mA/cm² and a polymerisation time of 40 s. The minimum detectable penicillin concentration with the bilayer potentiometric biosensor was 0.3 µM and the linear concentration range was 7.5–146 µM. The average percentage recovery of penicillin that was found in amoxycillin 500 mg was 113±24 %. The determination of penicillin in milk was fraught with problems of non‐specific binding of penicillin to the milk.     

聚合电流对锂/聚吡咯电池正极电化学行为的影响

在Pt微盘电极上用恒电流技术在电流密度为0.05-10 mA·cm-2范围合成了1 滋m厚度的聚吡咯(PPy)膜. 采用循环伏安(CV)、计时电势、交流阻抗(EIS)技术考察了不同聚合电流下得到的聚吡咯的电化学行为. 结果表明, 最佳聚合电流区间为1-5 mA·cm-2, 对应的电势一般在3.9-4.1V (vs Li/Li+)之间, PPy的掺杂度为30%左右. 在这一聚合电流密度范围得到的PPy具有较大的电化学容量, 较佳的电化学反应可逆性能、较高的氧化还原电势数值和稳定性能. 处于氧化态的聚吡咯具有优良的导电性. 上述条件下得到的PPy适合于作为锂离子二次电池的正极材料. 适当选择电流, 可以得到有相对完整的共轭仔键的长链结构的PPy 膜.     

聚吡咯为基底的葡萄糖酶微电极的研究

本文将聚吡咯(PPy)修饰的铂微电极以牛血清白蛋白(BSA)为载体,用戊二醛与萄葡糖氧化酶(GOD)交联,制成了萄葡糖酶微电极(GOD/PPy/Pt)。电极的寿命可达21天。萄葡糖浓度在1.0×10~(-4)～3.0×10~(-3)mol/L范围内有线性关系。     

Sensitivity and Selectivity of Polypyrrole Based AC‐Amperometric Sensors for Electroinactive Ions – Frequency and Applied Potential Influence

Oxidation/reduction of polypyrrole films coupled with ion exchange on the polymer/solution interface can be utilized for amperometric sensing of electroinactive ions. Anion or cation exchanging films (polypyrrole doped by chloride or poly(4‐styrenesulfonate) ions, respectively) can be used to determine common anions (as Cl^?, NO , SO etc) or cations (K⁺, Na⁺, Li⁺, Ca²⁺, Mg²⁺) under conditions of alternating current (AC) amperometry in the range 10^?4–1 M. A sensitivity can be tuned by choosing appropriate electrode potential, corresponding to polypyrrole oxidation (anion‐exchanging films) or reduction (cation‐exchangers). Electrochemical impedance spectroscopy and AC‐voltammetry studies have shown that applied frequency and potential could also affect the observed dependence of the signal (admittance or AC‐current) on ion concentration. For high frequency the sensitivity is higher but selectivity lower, due to influence of solution conductivity on the response. For low frequencies the sensitivity is lower; however, a selectivity increase was observed due to diverse mobility of ions in the polymer film. Selectivity of AC‐amperometric responses was studied both in separate and mixed solutions.     

电聚合导电聚吡咯的合成研究

用电化学法将吡咯单体聚合在电极上，于不同支持电解质的水溶液中得到聚吡啶薄膜。研究了电解质浓度、电解质阴离子种类及聚合时间对聚吡咯薄膜导电性能的影响。     

聚吡咯纳米线的恒电位合成及形貌分析

采用恒电位法,直接在石墨电极表面快速合成聚吡咯纳米线,并重点研究了聚吡咯纳米线的生成过程及形貌变化规律。结果表明,聚吡咯纳米线的生成包括成核和生长过程,纳米线的形貌随聚合条件的不同而变化,直径随聚合电位、吡咯单体浓度、电解质浓度的升高而增大,这是由于不同聚合条件下聚吡咯的成核速率不同引起的。     

Phenolphthalein immobilized membrane for an optical pH sensor

A phenolphthalein immobilized cellulose membrane for an optical pH sensor was described. The phenolphthalein was first reacted with the formaldehyde to produce a series of prepolymers with many hydroxymethyl groups. In this paper, the prepolymers was abbreviated to phenolphthalein-formaldehyde (PPF). Then the PPF was covalently immobilized to the diacetylcellulose membrane via hydroxymethyl groups. Finally the membrane was hydrolyzed in the 0.1 M NaOH solution for 24 h to reduce the response time. Advantageous features of the pH-sensitive membrane include (a) a large dynamic range from pH 8.0 to 12.50, or even broader, (b) rapid response time (2–30 s), (c) easy of fabrication, and (d) a promising material for determination of high pH values. The immobilized PPF has a broader dynamic range from 8.0 to 12.50 than the free phenolphthalein from pH 8.0 to 11.0, and this was due to the newly produced methylenes in our investigation.     

间接等离子体聚合制备聚吡咯薄膜

通过吡咯在氩辉光放电气流下游区域的间接等离子体聚合作用制备了聚吡咯薄膜。研究了聚合膜的沉积速率，用ＦＴＩＲ、ＸＰＳ、ＳＥＭ、ＸＲＤ、ＴＥＤ等手段表征了聚合膜的结构和形态。结果表明，聚合膜完整地保留了吡咯单体的共轭结构，显示出较高的导电性，化学掺杂碘以后膜的室温电导率为１０－７～１０－６Ｓ／ｃｍ。