测定尿液中血红蛋白含量的共振散射新方法

在酸性介质中,锌试剂和血红蛋白通过静电引力作用生成离子缔合物,从而导致体系的共振散射信号增强,据此建立了一种简单、灵敏、快速测定血红蛋白含量的共振散射光谱新方法。在优化的实验条件下,血红蛋白质量浓度在0.04~1.20μg/m L范围内与体系共振散射强度的增加值(ΔI)呈良好的线性关系(λ=605 nm),线性回归方程为ΔI=113.43ρ-0.517 0(μg/m L),相关系数r=0.998 3,方法检出限为0.02μg/m L。将该方法应用于尿样中血红蛋白含量的检测,回收率为93.40%~106.66%,结果令人满意。     

电化学石英晶体微天平研究重氮盐的电还原过程

采用压电电化学石英晶体微天平(EQCM)技术研究了硫酸重氮盐在裸金电极(Au)和多壁碳纳米管(MWCNTs)修饰金电极上的电还原行为,比较了2种电极上电沉积质量和稳定性。结果表明,相同循环伏安扫描条件下,重氮盐在金电极和MWCNTs/Au电极上的工作曲线还原峰电位相同,后者的初始峰电流低于前者,QCM数据显示重氮盐在MWCNTs/Au电极上沉积速度优于金电极,饱和沉积量是金电极上的3倍,表明碳纳米管催化了还原过程并增大了电极的表面积;在磷酸中性缓冲溶液中浸泡7 d后,重氮盐修饰后的MWCNTs/Au电极表面质量变化比金电极小0.28ng,表明修饰后的MWCNTs/Au电极略稳定。     

脒基硫脲对酸性硫酸盐溶液中铜电沉积过程影响的研究

研究添加剂对电沉积的作用机理及添加剂用量对镀层结构的影响,有利于开发一种更好效果的添加剂。为了获得良好的镀层,硫脲及其衍生物作为添加剂已经广泛应用于电镀工业中,脒基硫脲(GTU)作为电镀添加剂,采用循环伏安法(CV)和电化学石英晶体微天平(EQCM)技术,考察GTU在酸性溶液中对铜沉积机理的影响。CV结果表明,脒基硫脲对铜电沉积有抑制作用;QCM分析表明,当镀液中含有GTU时,铜阴极沉积和阳极溶出过程的M/n分别为61.50,64.12 g/mol,表明电极反应过程中,Pt/Cu电极表面的铜离子沉积从二电子过程过渡到单电子过程,添加剂的最佳浓度为10 mmol/L。     

电化学石英晶体微天平研究磷酸钙盐的快速电沉积过程

利用电化学石英晶体微天平(EQCM)技术,研究了磷酸钙盐在0.01 mol·L~(-1) Ca(NO_3)_2+0.006 mol·L~(-1)NH_4H_2PO_4溶液中的电沉积行为。从正电位往负极扫时,频率在1.1 V开始下降,达到磷酸钙盐沉积的p H值;而往上述溶液中加入少量的对苯醌、0.2 V时,频率开始下降。表明对苯醌改变了溶液中电子传递的路径,使得沉积电位升高,从而减少了氢气的析出,即增大了沉积的磷酸钙盐量,也提高了致密度和稳定性。     

石英晶体振荡法在气体中微量水分检测中的应用

介绍了基于石英晶体微天平(QCM)技术的石英晶体振荡法的基本原理和气体中微量水分检测的公式,总结了石英晶体振荡法在气体中微量水分检测方面的特点和应用范围。     

四氨基镍酞菁在金电极上成膜过程的研究

采用循环伏安法（CV）和石英晶体微天平技术（QCM）对四氨基镍酞菁（NiTAPc）在金电极上的聚合成膜过程进行了研究,讨论了扫描速率、溶剂、支持电解质及单体浓度对其成膜过程的影响,考察了该聚合膜在无单体电解质溶液中的氧化还原行为及稳定性。借助电化学石英晶体微天平(QCM)重点讨论了过程溶液中离子在膜中传输的机理。     

鸟嘌呤和腺嘌呤吸附和电氧化行为的电化学石英晶体微天平研究

基于压电电化学石英晶体微天平(EQCM)技术,研究了腺嘌呤(A)和鸟嘌呤(G)在裸金电极和多壁碳纳米管(MWCNTs)修饰金电极上的吸附和电氧化行为。结果表明,在金电极上,A的吸附量和氧化电流均比G大,而在MWCNTs/Au电极上,A和G可类似地吸附,但其氧化峰电位负移且氧化峰电流增大,表明MWCNTs对A和G的氧化具有催化作用。实验发现,A和G在裸金电极上氧化的电子转移数分别为5.4(RSD=±2.3%)和1.9(RSD=±1.3%),而在MWCNTs/Au电极上的氧化电子转移数分别为5.1(RSD=±1.8%)和1.5(RSD=±1.6%)。     

血红蛋白的电化学和电分析化学研究进展

血红蛋白是一种重要的生物大分子,在生命活动中起着重要作用,有关它的电化学和电子转移过程的研究对于揭示生命过程的本质有着重要意义。对血红蛋白在裸电极和化学修饰电极上的电化学行为和电催化机理进行了综述,并介绍了可用于检测血红蛋白的电化学分析方法及应用。     

电化学石英晶体微天平研究电沉积镍

为研究不同温度和pH值对电还原硫酸镍过程的影响,优化电沉积镍的条件,采用石英晶体微天平结合电化学工作站循环扫描方法,通过改变pH、沉积液温度等不同条件,研究镍的电沉积速率的变化规律。电极表面频率的下降速率和扫描电镜结果显示,缓冲系有利于晶粒细化,温度升高使得电沉积镍的沉积速率增大。     

Novel preparation and electrochemical study of the dithiocarbamate polymer/thiuram disulfide redox system

Four dithiocarbamic polymers have been prepared by reacting a linear poly(ethylenimine) polymer (MW 50 000) with CS₂. Depending on the reaction conditions the resulting polymeric products contained, up to two sulfur atoms per one nitrogen atom (40% w/w). These polymers are soluble in dimethylsulfoxide and insoluble in acetonitrile solutions. In both solvents they are electrochemically active, in the latter case as cast film on glassy carbon or platinum electrodes. Specifically, upon oxidation the polymers turn into highly crosslinked (S–S bonds) form. The crosslinked polymer preserves partial electroactivity, although lower than expected due to its rigid structure but, more importantly, it is permeable to solvents and can act as an active matrix for electroactive species from the bulk solution. The switch between anionic and non-ionic (crosslinked) forms of the dithiocarbamic polymer results in transport of the solvent and lithium counterions between the film and the bulk solution.     

Ion exchange properties of polypyrrole studied by electrochemical quartz crystal microbalance (EQCM)

The electrochemical polymerization of pyrrole in aqueous solution was studied as a function of a variety of parameters, such as magnitude of current density and monomer concentration. The possibility of quantitative replacement of counterions by solution anions was studied in detail using the electrochemical quartz crystal microbalance (EQCM) technique. It was found that the polymer structure can be manipulated, even after synthesis. The manipulation was revealed to be dependent on various factors, including the nature of the counterion and of the electrolyte concentration. On the basis of these observations, a two-layer structure is suggested for polypyrrole-based polymers. © 1999 Society of Chemical Industry     

Monitoring of formation and redox transformations of poly(Methylene blue) films using an electrochemical quartz crystal microbalance

An electrochemical quartz crystal microbalance and cyclic voltammetry have been used to monitor the growth of poly(methylene blue) films on gold during potential cycling between −0.6V and 1.0V vs. sce in sodium phosphate buffer (pH 8.2) and Na₂SO₄ solutions. Both the adsorption/desorption of monomer methylene blue and the formation of poly(methylene blue) film can be followed by microgravimetry. The response of the polymer films is significantly separated from that of the monomer species in solution. It has been proved that anion sorption/desorption occur during the redox transformation of the polymer, while cations play no role. Preliminary results on the complex protonation/deprotonation equilibria are also discussed.     

Electrochemical quartz crystal microbalance study of redox transformations of TCNQ microcrystals in concentrated LiCl solutions

Microcrystals of 7,7,8,8-tetracyanoquinodimethane (TCNQ) immobilized on gold surface have been investigated by combined cyclic voltammetry/chronoamperometry and piezoelectric nanogravimetry at an electrochemical quartz crystal microbalance (EQCM) in dilute and concentrated LiCl solutions. It is proved that TCNQ microcrystals even when TCNQ is reduced to its highly soluble Li⁺TCNQ⁻ salt can be studied in aqueous solutions when the water activity is decreased to a low level. At high electrolyte concentrations the voltammetric and chronoamperometric responses obtained for TCNQ microcrystals show the theoretically predicted pattern characteristic to the solid-solid phase transformation under the control of the nucleation and growth kinetics. The utilization of the idea presented in this work, i.e., using electrolyte of high concentrations (or decreasing the water activity by adding an indifferent component to the liquid phase in high concentration) can open up new vistas in the study of redox transformations of immobilized microcrystals which are soluble in water.     

基于纳米探针的压电重金属离子检测

文章通过在QCM（Quartz Crystal Microbalance,石英晶体微天平）表面形成纳米复合物引起质量变化来检测溶液中的痕量重金属离子。先让金属离子在羧基修饰的QCM表面进行络合吸附,然后加入羧基修饰的金纳米粒子,使之与QCM表面吸附的重金属离子结合,在QCM表面形成一层三明治结构的纳米复合物,引起QCM谐振频率明显下降。该方法大大提高了QCM检测重金属离子的灵敏度,且具有重现性好、传感器易再生等特点。     

EQCM study of polypyrrole modified electrodes doped with Keggin-type heteropolyanion for cation detection

The incorporation of a Keggin-type heteropolyanion, the phosphotungstate ([PW₁₂O₄₀]³⁻), into polypyrrole has been achieved during the electrochemical preparation of the polymer films in aqueous solution. The redox behaviour of these modified electrodes is described by using cyclic voltammetry (CV) and electrochemical quartz crystal microbalance (EQCM). The data allowed to estimate the doping level that indicates the extent of the heteropolyanion insertion. It is found that the polymer films, in aqueous solution, exhibit sensibility to cations, namely to Na⁺.     

Application of the electrochemical quartz crystal microbalance technique to copper sonoelectrochemistry: Part 1. Sulfate-based electrolytes

The applicability of the electrochemical quartz crystal microbalance technique in an ultrasonic field created by an ultrasound probe is demonstrated for the electrodeposition of copper. Cyclic voltammetry and potentiostatic depositions in acidic sulfate-based copper electrolytes were performed at different ultrasonic intensities. The electrochemical quartz crystal microbalance was operated in ultrasonic fields with intensities up to 30 W cm⁻². For cyclic voltammetry, potential resolved and averaged (apparent) current efficiencies were calculated from mass and charge data in function of the amplitude of the ultrasonic horn. Ultrasound slightly affected the current efficiencies during copper deposition in cyclic voltammetry, but did not change the efficiencies during dissolution. During potentiostatic depositions the current efficiency increased from 84% to almost 100% upon application of ultrasound. Morphology of deposits prepared by potentiostatic depositions was analyzed by scanning electron microscopy, and found to be different at high ultrasonic intensities.     

Electrochemical behaviors of poly(ferrocenylsilane) solutions

The electrochemical behaviors of two kinds of poly(ferrocenylsilanes) (PFS) with different substituent groups in CH₂Cl₂ solutions were investigated by means of cyclic voltammetry (CV) and electrochemical quartz crystal microbalance. The results demonstrated that the CV processes of the PFS on the glass carbon electrode surface in CH₂Cl₂ solutions are the diffusion‐controlled reversible processes. The oxidative state of PFS forms an adsorption layer on the electrode surface during the oxidation process. The interaction of active ferrocene centers along the main chain induces the stepwise redox process, and makes the CV waves of the PFS solutions present two couples of peaks. The diffusion coefficients of PFS in CH₂Cl₂ solution are much larger than those of PFS in films. The different electrochemical behaviors of the two PFS solutions indicated that the molecular structure of polymer has influence on the electrochemical properties of the PFS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 789–794, 2007     

Electrochemical Polymerization of 3-Methoxyaniline and Characterization of the Obtained Polymer

ABSTRACT

Electropolymerization of 3-methoxyaniline on platinum electrode in acid medium was carried out under different reaction conditions such as temperature, current density, hydrochloric acid, and monomer concentrations with duration time. The initial rate of the electropolymerization reaction is small and the orders are found to be 0.99, 0.98, and 0.97 with respect to current density, acid, and monomer concentrations, respectively. The apparent activation energy (E_a) is found to be 59.673 KJ mol^?1. The rate law is RP = K₂[D]^0.99 [HCl]^0.98 [M]^0.97. The obtained polymer films were characterized by ¹H-NMR, elemental analysis, IR, and cyclic voltammetry. The mechanism of the electropolymerization reaction has also been discussed. The thermogravimetric analysis (TGA) was used to confirm the proposed structure and determination of the number of water molecules in the polymeric chain unit. X-ray and scanning electron microscopic analysis were used to investigate the surface morphology.