硫化物在乙酰二茂铁修饰碳糊电极上的电化学行为及电分析

研究了S2-在乙酰二茂铁(AFc)修饰碳糊电极(AFc/CPE)上的电催化氧化行为及其电化学分析方法。实验结果表明,AFc/CPE对S2-的电化学氧化具有良好的催化作用。用计时电流法(CA)测定了S2-在AFc/CPE上的电催化氧化反应速率常数k为(2.60±0.05)×105 L.mol-1.s-1。用方波伏安法(SWV)测得催化氧化峰电流与S2-的浓度在5.0×10-5～1.0×10-3 mol.L-1范围内呈良好线性关系,检出限(S/N=3)为1.3×10-7 mol.L-1,同时运用SWV法对造纸废水水样中S2-的含量进行了电化学定量测定。     

米吐尔在离子液体修饰碳糊电极上的电化学行为及其测定

用离子液体1-庚基-3-甲基咪唑六氟磷酸([HMIM][PF6])作修饰剂制备了离子液体修饰碳糊电极(IL/CPE).在0.5 mol/L HAc-NaAc(pH=4.8)缓冲溶液中,采用循环伏安法(CV)和方波伏安法(SWV)研究了米吐尔在该修饰电极上的电化学行为,建立了测定米吐尔的新方法.研究表明,米吐尔在IL/CPE上的氧化、还原峰电位差比其在裸碳糊电极(CPE)上的小,而峰电流却显著增加,说明IL/CPE对米吐尔有电催化作用;共存物对苯二酚干扰米吐尔的测定,通过方波伏安法可以消除其干扰.在方波伏安曲线上,米吐尔的还原峰电流与其浓度在1.0×10-7 ～2.0×10-5 mol/L范围内呈线性关系,检出限为3.0×10-8 mol/L.该法可用于照相废液中米吐尔的测定.     

延胡索酸泰妙菌素在碳糊电极上的电化学性质及电分析方法

运用循环伏安法(CV)、计时电流法(CA)和计时电量法(CC)研究了延胡索酸泰妙菌素(Tiamulin fumarate,TF)在碳糊电极(Carbon Paste Electrode,CPE)上的电化学及其电化学动力学性质。结果表明,TF在CPE上的电化学过程是一不可逆的氧化过程,氧化峰电位Ep为0.772 V。在扫描速度10～1 000 mV.s-1范围内,其氧化峰电流Ip与扫描速度v呈良好的线性关系,表明TF在CPE上的伏安行为是一受吸附控制的过程。方波伏安(SWV)法结果表明TF氧化峰电流与其浓度在5.0×10-7～1.0×10-5mol.L-1及1.0×10-5～1.0×10-4mol.L-1范围内均呈良好的线性关系,相关系数r分别为0.9980及0.9966,检出限(S/N=3)为5.8×10-8mol.L-1,相对标准偏差(RSD)为0.8%～2.8%,加样回收率为97.6%～102.0%。据此建立了TF含量的电化学测定方法。该方法简便快捷,测定结果令人满意。     

双酚A在SDS现场自组装膜与[bupy]PF6复合修饰碳糊电极上的电催化氧化及电分析方法

研究了双酚A(BPA)在十二烷基硫酸钠(SDS)现场自组装膜与离子液体N-丁基吡啶夫氟磷酸盐([ bupy]PF6)复合修饰碳糊电极(SDS-[ bupy]PF6/CPE)上的电催化氧化行为和电化学动力学性质.实验结果表明,在SDS-[ bupy]PF6/CPE上BPA发生了一受扩散控制的不可逆电化学氧化过程,用循环伏安(CV)法和计时电流(CA)法测得BPA在SDS-[bupy]PF6/CPE上的电极反应过程动力学参数.用方波伏安(SWV)法测得BPA氧化峰电流(Ipa)与其浓度在1.0×10-5～ 1.0×10-3 mol/L范围内呈良好的线性关系,线性方程为Ipa(μA) =2.635 +51.30c( 10-3 mol/L),r =0.998 1,检测限(S/N=3)为3.01×10-7 mol/L,同时运用SWV法对湖水样品中双酚A的含量进行了电化学定量测定.     

马来酸氯苯那敏在碳糊电极上的电化学性质及电分析方法

运用循环伏安法(CV)、控制电位电解库仑法(BE)、计时电流法(CA)和计时电量法(CC)研究了马来酸氯苯那敏(CPM)在碳糊电极(CPE)上的电化学及其电化学动力学性质.研究结果表明,CPM在CPE上的电化学过程是一不可逆电化学氧化过程,氧化峰电位(Vp)为0.953V.在扫描速率10～1000mV·s-1范围内其氧化峰电流与扫描速率平方根(v1/2)呈良好的线性关系,表明CPM在CPE上的伏安行为是一受扩散控制的电极过程.经方波伏安法(SWV)考察发现CPM氧化峰电流与其浓度在1.0×10-6～6.0×10-4mol·L-1范围内呈良好的线性关系,r=0.9997,检出限5.0×10-7mol·L-1,RSD为2.6%～2.9%,加样回收率为100%～102%,据此建立了CPM含量的电化学测定方法.     

多壁纳米管修饰电极电催化3,4-二羟基苯甲酸研究

应用循环伏安(CV)和方波伏安(SWV)法研究3,4-二羟基苯甲酸(DHBA)在多壁碳纳米管修饰的玻碳电极上的电化学行为.实验表明:该修饰电极对DHBA有较强的电催化作用.由方波伏安法测定的氧化峰电流在DHBA浓度为4.0×10-6~1.0×10-4mol/L和2.0×10-4~8.0×10-4mol/L范围内分段呈线性变化关系;相关系数各为0.9995和0.9992,检测限1.0×10-6mol/L.     

抗菌素痢菌净的电化学分析

采用循环伏安法(CV)、差分脉冲伏安法(DPV)和方波伏安法(SWV)在玻碳电极(GCE)上对痢菌净进行了电化学研究.实验表明:在pH=6.6的B-R缓冲底液中,痢菌净在-0.85伏左右有一个明显的可逆氧化还原峰,考察了不同底液及pH值、扫描速度、富集时间和静止时间的影响.DPV法其线性范围为2.0×10-6mol/L～2.0×10-3mol/L,检出限为5.0×10-8 mol/L;SWV法其线性范围为2.0×10-6 mol/L～1.0×10-3 mol/L,检出限为2.0×10-8 mol/L.并对痢菌净的电极反应机理进行了初步探讨,该方法操作简单、灵敏,可用于实际药品测定.     

Electrocatalytic Oxidation and Electrochemical Determination of Methocarbamol at [BnMIM]PF6 Modified Carbon Paste Electrode

研究了美索巴莫(MET)在离子液体1-苄基-3-甲基咪唑六氟磷酸盐[BnMIM]PF6修饰碳糊电极([BnMIM]PF6/CPE)上的电催化氧化行为和电化学动力学性质,并用循环伏安法(CV)、计时电流法(CA)测得MET在[ BnMIM]PF6/CPE上的电极反应过程动力学参数.实验结果表明,MET在[BnMIM]PF6/CPE上发生了受扩散控制的不可逆电化学氧化过程.用方波伏安法(SWV)测得MET氧化峰电流(Ipa)与其浓度在3.0×10-5～1.0×10-2 mol·L-1范围内呈良好线性关系,检出限(S/N=3)为3.3×10-6 mol· L-1.同时运用SWV法对市售美索巴莫片进行电化学定量测定,RSD为1.5％～2.5％,加标回收率为98％～ 99％.     

生理介质中硝普钠在玻碳电极上的电化学性质及电分析方法研究

研究了生理介质中硝普钠(SNP)在玻碳电极(GCE)上的直接电化学行为。结果表明,在电位窗口-0.60~0.30 V(vs.SCE)及0.15 mol/L NaCl水溶液中,SNP的电化学过程呈现出一准可逆的氧化还原过程,△E=110 mV,还原峰电位(Epc)和氧化峰电位(Epa)分别为-0.200 V和-0.090 V。在扫描速度10~1 000 mV/s范围内其还原峰电流和氧化峰电流与扫描速度的平方根(v1/2)呈良好的线性关系,表明SNP在GCE上的伏安行为是一受扩散控制的电化学过程。用循环伏安法(CV)、计时电量法(CC)和计时电流法(CA)测定了SNP在GCE上的电极过程动力学参数如电荷传递系数α,扩散系数D以及表观速度常数Kf。同时运用方波伏安法(SWV)研究了SNP在GCE上的方波伏安行为,发现SNP的还原峰电流与其浓度在2.0×10-5~1.8×10-2mol/L范围内有良好的线性关系,相关系数R=0.9973;检出限为1.0×10-5mol/L。据此,建立了测定SNP含量的直接电化学分析方法,测定结果的相对标准偏差在0.8%~1.4%之间;标准加入回收率在96.3%~100.5%之间。该法简单、快捷、准确,测定结果令人满意。     

甘草苷在悬汞电极上的电化学行为及方法研究

运用循环伏安法(CV)考察了甘草苷在悬汞电极(HMDE)上的电化学还原行为,在-0.7~-1.7 V(vs.SCE)电位窗口及0.10 mol/L(NH4)2SO4溶液中甘草苷在HMDE上的循环伏安行为是一在低扫描速度(<100 mV/s)下受吸附控制,在高扫描速度下受扩散控制的不可逆还原过程,还原峰电位(Epc)为-1.491 V。运用计时库仑法(CC)、计时电流法(CA)测定并计算了甘草苷的电荷传递系数α、扩散系数D以及表观速率常数Kf等电极过程动力学参数。初步探讨了甘草苷在HMDE上的反应机理,同时运用方波伏安法(SWV)研究了甘草苷在HMDE上的方波伏安行为,还原峰电流与其浓度在1.2×10-6~1.2×10-5mol/L及1.2×10-5~1.2×10-3mol/L范围内呈良好的线性关系,相关系数R=0.9936及0.9966,检出限8.0×10-7mol/L,据此可建立直接电化学测定甘草苷含量的方法。     

卡马西平在nano-TiO2/[BnMIM] PF6修饰碳糊电极上的电催化氧化及电分析方法

运用循环伏安法(CV)、计时电流法(CA)、计时库仑法(CC)、方波伏安法(SWV)研究了卡马西平(CBZ)在纳米二氧化钛(nano-TiO2)与离子液体1-苄基-3-甲基咪唑六氟磷酸盐([BnMIM]PF6)复合修饰碳糊电极(nano-TiO2-[BnMIM] PF6/CPE )上的电化学行为、电化学动力学性质及电分...     

Electrochemical techniques for the removal of Reactofix Golden Yellow 3 RFN from industrial wastes

Electrochemical methods for pollution abatement have been shown to be viable alternatives or complementary to biological treatment in some instances, especially when pollutants are recalcitrant to biological processing. Electrochemical oxidation and reduction have been found successful in decomposing the most resilient compounds, and electrolysis is assigned an important role in the elucidation of the electrode process. Small well-defined cathodic and anodic peak were observed that on controlled-potential electrolysis (CPE) reduced substantially with a considerable decrease in color and absorbance. The rate of decrease of the current and absorbance was found to exhibit a first-order dependence. The COD of the solutions showed a decrease from 1416 to 352 mg/L. No peak could be observed in the voltammograms after CPE, indicating the absence of any electroactive substance left in the solutions. Results show that electrochemical reduction is a superior technology for treatment of dyes, as there is no simultaneous addition of anions, such as sulfate or chloride.     

Voltammetric determination of ethinylestradiol at a carbon paste electrode in the presence of cetyl pyridine bromine

Electrochemical behaviors of ethinylestradiol at a carbon paste electrode (CPE) in the presence of cetyl pyridine bromide (CPB) are investigated by electrochemical techniques. Compared with that at a CPE without CPB, the oxidation peak potential of ethinylestradiol shifts negatively and the peak current is increased significantly, due to the enhanced accumulation of ethinylestradiol via electrostatic interaction with CPB at the hydrophobic electrode surface. It is verified by the influences of different kinds of surfactants on the electrochemical signals of ethinylestradiol. Some parameters such as pH, scan rate, accumulation potential and accumulation time on the oxidation of ethinylestradiol are optimized. Under optimal conditions, the oxidation peak current is proportional to ethinylestradiol concentration in the range of 5.0 x 10(-8) to 2.0 x 10(-5) mol L(-1) with a detection limit of 3.0 x 10(-8) mol L(-1) for 150 s accumulation by linear sweep voltammetry (LSV). The proposed procedure is successfully applied to determine ethinylestradiol in pharmaceutical formulation (Levonorgestrel and Etinylestradiol tablets) and the results are satisfying compared with that of high-performance liquid chromatography (HPLC).     

Electrochemical Behavior of o‐Nitrophenol at Hexagonal Mesoporous Silica Modified Carbon Paste Electrodes

A hexagonal mesoporous silica (HMS) modified carbon paste electrode (CPE) was fabricated and characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods (ferrocene as a probe). The electrochemical behavior of nitrophenol (o‐NP) at the HMS modified electrode (HMSCPE) was investigated. Compared with CPE, a well‐defined reduction peak and a remarkably peak current response was observed. It is indicated that mesoporous HMS exhibited remarkable enhancement effects on the electrochemical reduction of o‐NP. The electrochemical reduction mechanism was also discussed. Consequently, a simple and sensitive electrochemical method was proposed for the determination of o‐NP, which was used to determine o‐NP in waste water samples.     

基于表面活性剂增敏有序介孔SiO2修饰碳糊电极测定L-色氨酸

利用水热法合成得到有序介孔二氧化硅( OMS),采用X射线衍射、N2吸附-脱附、透射电镜等技术对其进行了表征。制备OMS修饰碳糊电极( OMS/CPE),采用循环伏安和交流阻抗技术考察了修饰电极的电化学性能,发现与裸碳糊电极(CPE)相比,OMS/CPE具有更大的电活性面积和更快的电子传导速率。研究了L-色氨酸(L-Trp)在表面活性剂十二烷基磺酸钠(SDS)存在下,在OMS/CPE上的电化学行为和动力学性质,结果表明,OMS和SDS具有良好的协同作用,能明显增加L-Trp的响应信号; SDS存在下,L-Trp在修饰电极上的电化学氧化是2电子和2质子参加的不可逆过程,电极过程受吸附控制。优化了表面活性剂浓度、富集时间、富集电位、介质 pH 值等测定参数,在最优条件下, L-Trp 氧化峰电流与其浓度在8.0×10-8~4.0×10-6 mol/L范围内呈良好线性关系,检出限为7.0×10-8 mol/L(S/N=3)。本方法用于氨基酸口服液样品的加标回收检测,回收率为99.6％~102.6％。     

Uranyl sensor based on a N,N′-bis(salicylidene)-2-hydroxy-phenylmethanediamine and multiwall carbon nanotube electrode

The electrochemical determination of uranyl was investigated by using carbon paste electrode modified with a Schiff base namely N,N??-bis(salicylidene)-2-hydroxy-phenylmethanediamine (SHPMD/CPE) and also in the presence of carbon nanotube (SHPMD/CNT/CPE). The both modified electrodes displayed an irreversible peak at E _pa?=?0.798?V versus Ag/AgCl. The electrocatalytic reduction of uranyl has been studied on SHPMD/CNT/CPE, using cyclic and differential pulse voltammetry, chronocoulometry and linear sweep techniques. Electrochemical parameters including the diffusion coefficient (D), the electron transfer coefficient (??), the ionic exchange current (i) and the redox reaction rate constant (K) were determined for the reduction of uranyl on the surface of the modified electrodes. Linear range concentration is 0.002?C0.6???mol?L^?1 and the detection limit of uranyl is 0.206?nmol?L^?1. The proposed method was used to detect uranyl in natural waters and good recovery was achieved.     

十六烷基三甲基溴化铵修饰碳糊电极线性扫描伏安法测定尿液中尿酸

本文提出了以十六烷基三甲基溴化铵修饰碳糊电极（CTAB／CPE）直接测定尿酸（UA）的新方法,用线性扫描伏安法（LSV）研究尿酸的电化学行为。在0.1mol／L磷酸盐缓冲溶液（PBS,pH=7.4）中,尿酸在CTAB／CPE上于0.160V处产生一个灵敏的氧化峰,氧化峰电流Ip与尿酸浓度（CuA）在1.0&#215;10^-5—1.0&#215;10^-3mol／L范围内呈良好的线性关系,相关系数为0.9940,检出限为1.0&#215;10^-6mol／L。该方法简单实用,可以直接用于人体尿液中尿酸的检测。     

Ionic liquid-functionalized graphene as modifier for electrochemical and electrocatalytic improvement: comparison of different carbon electrodes

Electrochemical activities of typically electrochemical targets at three kinds of modified carbon electrodes, i.e. carbon ionic liquid electrode (CILE), graphene/carbon paste electrode (CPE), and ionic liquid-functionalized graphene (IL-graphene)/CPE, were compared in detail. The redox processes of the probes at IL-graphene/CPE were faster than those at CILE and graphene/CPE from cyclic voltammetry. An electrochemical method for the simultaneous determination of guanine and adenine was described with detection limits of 6.5 × 10⁻⁸ mol L⁻¹ (guanine) and 3.2 × 10⁻⁸ mol L⁻¹ (adenine). Single A → G mutation of sequence-specific DNA could be discriminated by the IL-graphene/CPE.     

Electrochemistry of riboflavin-binding protein and its interaction with riboflavin

Riboflavin-binding protein (RBP, a carrier of riboflavin) plays an essential role in embryo development. Electrochemical studies of the riboflavin–RBP interactions have been so far limited to changes in polarographic and voltammetric responses of riboflavin because of lack of methods capable to detect electrochemical changes in the RBP responses. Here we used constant current chronopotentiometric stripping analysis (CPSA) with the hanging mercury drop electrode (HMDE) and square wave voltammetry (SWV) with carbon paste electrode (CPE) to investigate RBP. We found that CPSA of RBP produces electrocatalytic peak H, capable to discriminate between apoprotein and holoprotein forms of RBP. This peak is suitable for studies of RBP–riboflavin interaction at nanomolar concentrations. We observed no sign of a release of riboflavin from holoprotein adsorbed at the HMDE surface. SWV at CPE required higher concentrations of RBP and displayed almost identical oxidation peaks of apoprotein and holoprotein.     

Enhanced reduction and determination of trace thyroxine at carbon paste electrode in the presence of trace cetyltrimethylammonium bromide.

The electrochemical response of thyroxine (T4) at a carbon paste electrode (CPE) in the presence of cetyltrimethylammonium bromide (CTAB) was investigated. It gave a well-defined oxidation peak at 0.80 V and a sensitive reduction peak at 0.40 V. Compared with the indiscernible signal in the absence of CTAB, the reduction current of T4 at CPE was greatly enhanced in the presence of CTAB, due to the interactions between T4, CTAB and the hydrophobic electrode surface. The electrode process of T4 was explored by cyclic voltammetry and chronocoulometry. The effect of surfactants on the reduction reaction proved that bromide ions (Br(-)) in CTAB might form special ion complexes with T4 via a special interaction with the iodine atoms on T4, which would activate the reduction of T4. The sensitive and selective reduction of T4 in this system was applied to the determination of T4 in drugs; a detection limit of 6.5 x 10(-9) M was obtained (sigma= 3).