Electrochemical Behavior and Determination of Trifluoperazine at Decanethiol Self-Assembled Monolayer Modified Gold Electrodes

The electrochemical behavior of trifluoperazine at decanethiol self-assembledmonolayer (SAM) modified gold electrodes (i. e. C_(10) H_(21) SH/Au) has been studied,Trifluoperazine can effectively accumulate on C_(10) H_(21) SH/Au electrodes and generate asensitive anodic peak at about 0.63 V (vs. SCE) in 0.05 mol/L pH 9.4 Na_2 B_4 O_7 buffer solution.Under the selected conditions, the anodic peak current was linear to trifluoperazine concentrationin the range of 5.0 X 10^(-7)-3.O X 10^(-3) mol/Lwith correlation coefficient of 0.997, thedetection limit was 3.0 X 10^(-5) mol/L. This method was applied to the determination oftrifluoperazine in drug samples and the recovery was 97.3%-104.0% It was found that sodium dodecylsulfate (SDS) could make the anodic peak current increase. In the presence of SDS, the peak at about0.63 V turned into two peaks, resulting from the change of the electrochemical mechanism.

A New Thionine Modified Electrode by Anchorage to Bi-(2-aminoethyl)-aminodithiocarboxyl Acid Self-assembled Monolayers through Coordination with Cu^(2+#)

A new method for preparing chemically modified gold electrode by anchoring thionine to self-assembled bi - (2 -aminoethyl) -aminodithiocarboxyl acid(BANTC) monolayers through coordination with Cu2+ is described. This thionine modified electrode exhibits two-new redox couples.Two protons were involved in the electrochemical process undergone by the couple I in the pH range of 5.0-10.0. The apparent surface electron transfer rate constant is about 0.050s-1.

The Molecular Recognition Characteristics of ω-MercaptoMethoxy Poly(Ethylene Glycol) Self-assembled Monolayer at Gold Electrode and the Detection of Dopamine in Serum

Self assembled monolayers (SAMs) of to-mercapto methoxy poly(ethylene glycol)(MPEG) on gold electrode were used as a means to detect dopamine. Dopamine (DA) had good response at the MPEG film electrode and ascorbic acid (AA) was repelled from the SAMs. TheMPEG film is a biocompatible film, there was no adsorption of biosample and no inactivation atelectrode surface when it was used to detect DA in biosamples.

Voltammetric Response and Electrocatalysis of Glassy Carbon Electrode Modified with Monolayer Nickel Hydroxide

The glassy carbon (GC) electrode modified with a monolayer nickel hydroxide (GC/Ni(OH) 2) was prepared by immersion of GC substrate in 1.0×10 -3 mol/L NiSO 4 solution, and then cyclic voltammetric scanning in 0.20 mol/L KOH. Similarly, GC/Co(OH) 2 electrode was prepared too. The experiments showed that the voltammetric behavior of GC/Ni(OH) 2 electrode in 0.20 mol/L KOH is more stable than that of GC/ Co(OH) 2. It was found that the GC/Ni(OH) 2 electrode acts as an effective electrocatalysis for the oxidation of hydrazine.

Anion Adsorption on an Au Colloid Monolayer Based Cysteamine-Modified Gold Electrode

Anion adsorption behavior on Au colloid surface was investigated in virture of depositing monolayers of Au colloid on the self-assembled monolayers of cysteamine on a gold electrode. Po- tential-dependent anion adsorption-desorption waves via the nonfaradaic current were obtained by means of cyclic voltammetry at Au coltoid-modified gold electrodes in the potential range of -2 00-600 mV. The adsorption sequence in the order of adsorption peak potentials (Epa) is OH- >citrate3 ->H2PO4- >Cl->SO42->ClO4->NO3-. Among them, citrate3- exhibited an en- tirely irreversible adsorption. A rise in temperature can increase the rates of adsorption-desorp- tion and improve the reversibility of the adsorption-desorption of Cl-, SO42-, ClO4-, NO3- and H2PO-4. The adsorption peak potentials shifted more negatively for Ca. 63 mV as the anion con- centrations were increased by a decade factor. The change of pH from 7 to 1 slightly affected the adsorption peak potentials of Cl- and NO3-. Au colloids with a smaller size (16 nm) gave rise to a better reversibility of the adsorption-desorption process and lower adsorption currents. The ex- perimental results of citrate ions adsorption on Au colloid surface show that Au colloids with a smaller size prepared by sodium citrate method exhibited a higher stability in the solution in com- parison to those with larger sizes because of its higher ratio of charge/mass. In other words, the smaller gold nanoparticles are covered with citrate ions monolayer that can also be formed at larg- er gold nanoparticles by means of electrochemical scan.

Study of enzyme biosensor based on carbon nanotubes modified electrode for detection of pesticides residue

The paper describes a controllable layer-by-layer （LBL） self-assembly modification technique of multi-walled carbon nanotubes （MWNTs） and poly（diallyldimethylammonium chloride） （PDDA） towards glassy carbon electrode （GCE）, Acetylcholinesterase （ACHE） was immobilized directly to the modified GCE by LBL self-assembly method, the activity value of AChE was detected by using i-t technique based on the modified Ellman method. Then the composition of carbaryl were detected by the enzyme electrode with 0.01U activity value and the detection limit of carbaryl is 10^- 12 g L ^-1 so the enzyme biosensor showed good properties for pesticides residue detection.

Attachment of tyrosinase on mixed self-assembled monolayers for the construction of electrochemical biosensor

A mixed self-assembled monolayers （SAMs） of thioctic acid （T-COOH） and thioctic acid amide （T-NH2） were used to immobilize tyrosinase for fabricating biosensor. The results showed that the mixed SAMs prepared from solution at the ratio of 1：4 provided an excellent microenvironment for enzymatic reaction between tyrosinase and substrate. The biosensor exhibited a fast response and high sensitivity for sensing substrate.

Fabrication of ferrocenyl glutathione modified electrode and its application for detection of cadmium ions

l＇-cysteaminecarbonyl-1-glutathionecarbonyl-ferrocene （Fc-GSH） was synthesized from ferrocene dicarboxylic acid and reduced glutathione （GSH） with 4 steps. IR and 1^H-NMR were used to characterize the products. Then Fc-GSH was immobilized on the surface of gold electrode. Cyclic votammetry （CV） was adopted to investigate the electrochemical properties of this Fc-GSH modified electrode in the absence and presence of Cd^2＋ aqueous solutions. The peak oxidation potential （Ea） and reduction potential （Ec） of Fc-GSH modified electrode were observed at Ea= 0.74 V and Ec= 0.64 V （vs Ag/AgCl） before the accumulation of Cd^2＋. This redox process is a monoelectron chemical reaction. The anodic shift is about 80 mV in the presence of 20 nmol/L of Cd^2＋ aqueous solution. Moreover, this shift is in proportion to the concentration of Cd^2＋ when the concentration of Cd^2＋ is lower than 20 nmol/L. So the modified electrode can be used as probes to detect cadmium ions with the limit of 0.1 nmol/L by cyclic voltammetry.

Assessment of Defects and Collapsed Sites in Self-Assembled Alkanethiol Monolayer on Gold by Cyclic Voltammetry and A.C.Impedance

Self-assembly of octadecyl mercaptan on gold was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy (EIS). Results of CV experiments show thatthere are no structUral defects exposed directly to the redox couple in solution, but EISexperiments indicate that collapsed sites exist in the monolayer. A method to estimate the degree ofdisorder in the Au/thiol monolayer surface is proposed by using admittance plane plot.

DNA-modified electrodes (Ⅶ)——Preparation and characterization of DNA-bonded and DNA-adsorbed SAM/Au electrodes

Two kinds of DNA-modified electrodes were prepared by covalent and adsorptive immobilization of DNA onto self-assembled monolayers of 2, 2’-dithiodiethanol on gold electrodes and characterized by cyclic voltammetry, Xray photoelectron spectroscopy and scanning tunneling microscopy. The results suggest that the methods are satisfactory for the immobilization of DNA on electrodes.

4-巯基吡啶自组装修饰金电极的电化学性质及对抗坏血酸的测定

研究了 4 巯基吡啶自组装膜 (SAM)修饰金电极的制备及其电化学性质 ,并用于抗坏血酸 (AA)的测定。在pH 3.0盐酸 邻苯二甲酸氢钾缓冲溶液中 ,AA在SAM修饰金电极上产生一灵敏的氧化峰 ,峰电流与AA浓度在 4 .0× 10 - 6 ～ 1.0× 10 - 3mol L范围内呈良好的线性关系 ,检出限为 2 .7× 10 - 6 mol L ,相关系数为0 9978。该电极对多巴胺 (DA)有排斥作用 ,重现性良好 ,可用于AA的灵敏测定。

多巴胺在硫堇衍生化自组装膜修饰金电极上的伏安行为及其安培测定

研究了多巴胺（ＤＡ）在硫堇衍生化自组装膜修饰金电极（Ｔｈ－ＳＡＭ／ＡＵｕ）上的电化学行为。ＤＡ在该修饰电极上的△Ｅｐ～７０ ｍＶ，循环伏安峰形对称，氧还峰电流之比接近 １，为准可逆反应。研究了温度、ｐＨ对ＤＡ氧化还原的影响，并求得了其热力学参数。在选定的条件下，峰电流与ＤＡ的浓度在１．０ × １０－６～１．０×１０－３ｍｏｌ／Ｌ的范围内呈线性关系，相关系数为０．９９２３，可用于ＤＡ的灵敏测定。

L-半胱氨酸自组装修饰金电极-不可逆双安培测定阿魏酸

在裸金电极上制备了L-半胱氨酸自组装膜金修饰电极（L-Cys／SAM—Au／CME），将自组装膜修饰电极用于不可逆双安培体系，利用阿魏酸在L—Cys／SAM—Au／CME上的氧化和KMnO4在裸金电极上的还原，构建双安培检测新体系，建立了在外加电压为0V条件下，流动注射双安培法直接测定阿魏酸的新方法。在0．05mol／LH2SO4溶液中，该氧化峰峰电流与阿魏酸浓度在5．0×10^-7-8．0×10^-5mol／L范围内呈线性关系（r=0．9961，n=10），其线性回归方程为i（nA）=4．16×10^7C＋50，在1．0×10^-4 -1．0×10^-3mol／L范围内呈线性关系（r=0．9955，n=5），其线性回归方程为i（nA）=5．6×10^6C＋300，检出限为1．2×10^-7mol／L。连续测定2．0×10^-5mol／L阿魏酸溶液25次，电流值RSD为1．20％，进样频率为80样／h。该方法具有较宽的线性范围、较高的选择性和灵敏度，样品处理方法简单快速，适于在线分析。对阿魏酸钠盐注射液中阿魏酸的测定结果满意。

L-半胱氨酸修饰金电极对邻苯二酚和对苯二酚的电催化及分析应用

研究了L_半胱氨酸自组装膜修饰金电极的电化学行为,发现其对邻苯二酚和对苯二酚的电化学氧化具有明显的电催化作用 ,使它们的氧化电位降低 ,峰电流显著增大;初步探讨了电催化机理;将该膜电极用于对苯二酚的定量测定 ,发现其氧化峰电流与对苯二酚浓度在1.0×10-4～3.0×10-2 mol·L-1 范围内成良好的线性关系 ,相关系数0.9974 ,检出限为2.0×10-5 mol·L-1;用于照相显影液中对苯二酚的测定 ,获得满意结果。

自组装膜技术在电分析化学中的应用

本文介绍了自组装膜的类型。

自组装膜技术在电分析化学中的研究与应用

本文对自组膜（SAMs）在电分析化学中的研究和应用进行了比较全面的综述。SAMs是单分子膜化学修饰电极发展的最高形式，本文着重阐述了硫醇／金单分子层自组膜在微电极、生物电化学和生物传感器、液相色谱电化学、电催化、光谱电化学等电分析化学研究领域中的应用，并进行了展望。

对乙酰氨基酚在多壁碳纳米管L-半胱氨酸共组装修饰金电极上的电化学行为研究及其测定

在N，N-二环已基碳酰亚胺（DCC）存在介质下，通过酰氨键使羧基化的多壁碳纳米管（MCNTs）与L-半胱氨酸（L-Cys）缩合，功能化的MCNTs通过S-Au键自组装（SAMs）到金电极表面，制备了修饰电极（MCNTs-L-Cys-Au／SAMs-CME），并对电极的表面结构进行电化学表征。研究表明，该修饰电极对对乙酰氨基酚的电化学氧化具有明显的催化作用。同时，对其催化氧化的机理进行了初步探讨。将此修饰电极用于流动注射不可逆双安培（FI-IB）体系的构建，即利用对乙酰氨基酚在MCNTs-L-Cys-Au／SAMs-CME上的氧化和KMnO4在另一支铂电极上的还原构建了双安培检测体系，成功的建立了在外加电压为0V条件下流动注射双安培法直接测定对乙酰氨基酚的新方法。在0V外加电压下，在0．05mol／L硫酸载液中，该氧化峰峰电流与对乙酰氨基酚浓度在2.0×10^-6～2．0×10^-4mol／L范围内呈良好的线性关系，其线性回归方程为i（nA）=8．21×10^7C＋200（r=0．9984，n=9）；在2．0×10^-4～1．0×10^-3mol／L范围内呈线性关系，其线性回归方程为i（nA）=2．30×10^7C＋10^4（r=0．9938，n=4），方法检出限为1．0×10^-6 mol／L（S／N=3）；连续测定1．00×10^-4mol／L对乙酰氨基酚标准溶液20次，电流值RSD为2．7％，进样频率为90样／h。该方法具有较高的选择性和灵敏度。对乙酰氨基酚片中的对乙酰氨基酚的含量的测定，结果比较满意。

维生素B_1自组装膜修饰金电极对多巴胺、尿酸的电催化作用

用维生素B1(VB1)在金电极上进行自组装,制备了VB1自组装膜修饰金电极(VB1-Au/SAMs/CME)。利用循环伏安法初步研究了此自组装单分子膜修饰电极的电化学行为。结果表明:VB1在金电极表面具有特性吸附。以[Fe(CN)6]3-/4-氧化还原电对为探针,考察了VB1自组装膜修饰金电极的电化学性质,VB1自组装膜的存在对[Fe(CN)6]3-/4-的电子转移具有明显的阻碍作用。研究了多巴胺(DA)和尿酸(UA)在此电极上的电化学行为。实验结果表明,DA和UA在此电极上均可被电催化氧化。差分脉冲伏安(DPV)氧化峰电流与DA浓度在2.0×10-5～4.0×10-4mol/L范围内呈线性关系;测定UA的线性范围为6.0×10-5～2.2×10-4mol/L,而且可实现这两种物质的同时测定。

对乙酰氨基酚在L-半胱氨酸修饰金电极上的不可逆双安培测定

在裸金电极上制备了L-半胱氨酸自组装膜修饰电极(L-Cys/SAM-CME),研究了对乙酰氨基酚(AP)在L-Cys/SAM-CME上的电化学行为,结果发现该修饰电极对AP的氧化具有催化作用,与裸金电极相比,氧化峰电位降低了68mV,峰电流增大了1.2×10-5A。本文探讨自组装膜修饰技术用于构建不可逆双安培法的可行性,利用对AP在L-Cys/SAM-CME上的催化氧化和高锰酸钾在裸金电极上的还原构建双安培检测体系,建立了在外加电压为0V条件下流动注射双安培法直接测定对AP的方法。在0V外加电压下,0.05mol/L硫酸载液中,测得对AP的峰电流与其浓度在2.0×10-7mol/L^2.0×10-4mol/L范围内呈良好的线性关系(r=0.9986,n=13),检出限为9.4×10-8mol/L。连续测定1.00×10-4mol/L的AP溶液20次,电流值RSD为1.90%,进样频率为80样/h。

L-半胱氨酸修饰金电极电化学发光法测定罗红霉素

在裸金电极上制备了L-半胱氨酸自组装膜修饰电极(L-Cys-Au/SAM/CME)。考察了联吡啶钌和罗红霉素在此修饰电极上的电化学及其发光行为。结果表明,此修饰电极表现出了很好的电化学活性和电化学发光(ECL)响应。基于罗红霉素的存在可增大了联吡啶钌的发光强度,建立了测定罗红霉素片的电化学发光分析方法。在最佳实验条件下,罗红霉素浓度在1.0×10-7～1.0×10-4mol/L范围内与其相对发光强度呈线性关系,其线性回归方程为I=2×107C+384.02,r=0.9977;检出限(S/N=3)为1.0×10-7mol/L。连续测定1.8×10-5mol/L罗红霉素10次,发光强度的RSD为1.93%,表明此修饰电极具有较好的重现性,并将本方法用于罗红霉素片剂的检测。