A New Sensor for Simultaneous Determination of Tyrosine and Dopamine Using Iron(III) Doped Zeolite Modified Carbon Paste Electrode

A new chemically modified electrode is constructed based on iron(III) doped zeolite modified carbon paste electrode (Fe³⁺Y/ZMCPE). The new sensor could be used for the simultaneous determination of the biologically important compounds dopamine (DA) and tyrosine (Tyr). The measurements are carried out using differential pulse voltammetric (DPV) method. The prepared modified electrode shows voltammetric responses of high sensitivity, selectivity and stability for DA and Tyr under optimal conditions, which makes it a suitable sensor for simultaneous trace detection of DA and Tyr in solution. Application of the DPV method demonstrates that in the Briton Robinson buffer solutions (pH=5) containing 50 µmol/L Tyr, there is a linear relationship between the oxidation peaks and the concentrations of DA over the range of 0.1–200 µmol/L, with a detection limit of 0.05 µmol/L (S/N=3). For Tyr a linear correlation between oxidation peak current and concentration of Tyr over the range of 0.5–200 µmol/L (containing 50 µmol/L DA), with a detection limit of 0.08 µmol/L is obtained. The analytical performances of this sensor are evaluated for the detection of DA and Tyr in human serum and a medicine.     

碳糊电极阳极吸附伏安法测定氧氟沙星

碳糊电极阳极吸附伏安法测定氧氟沙星;氧氟沙星; 阳极吸附伏安法; 碳糊电极     

土豆汁修饰碳糊电极测定色氨酸的研究

本提出了用于测定色氨酸的土豆汁修饰碳糊电极，该电极选择性好，能有效地消除酪氨酸的干扰，在ｐＨ＝７．４的ＮａＨ２ＰＯ４－ＮａＯＨ生理缓冲液中，电极响应与色氨酸在９．８×１０＾－６～９．８×１０＾－５ｍｏｌ／Ｌ的浓度范围内呈线性关系，最低检出限是１．５×１０＾－６ｍｏｌ／Ｌ．并详细讨论了电极抗干扰能力与测定条件的关系。用该电极测定了实际样品氨基酸注射液中色氨酸的含量，结果与标准值吻合。     

丁二酮肟化学修饰碳糊电极测定微量钯

报道了丁二酮肟化学修饰碳糊电极用于测定微量钯的研究。实验表明，Pd（Ⅱ）浓度在1×10－4～5×10－7mol·L－1范围内呈良好的线性关系。对模拟样进行了测定。     

蒙脱石修饰碳糊电极测定苯酚的研究

本文报道蒙脱石修饰碳糊电极在醋酸盐缓冲溶液(pH=3.6)中,用微分脉冲伏安法测定苯酚。在+0.90 V(vs.Ag/AgCl)有一灵敏的氧化峰,伏安响应要比碳糊电极高得多.对测定苯酚的条件进行了研究,苯酚在0.1～1.0μg/ml范围内呈线性,检出限为40ng/ml,相对标准偏差为6.7％,平均回收率为97.2％。用此方法,不经分离直接测定饮料中的酚。还对苯酚在蒙脱石修饰碳糊电极上的反应机理进行了探讨。     

Flow Injection Determination of Hydrogen Peroxide Using a Carbon Paste Electrode Modified with a Manganese Dioxide Film

Abstract

A manganese dioxide film modified carbon paste electrode was developed for use as an amperometric sensor for the determination of hydrogen peroxide (H₂O₂) in ammoniacal aqueous solutions. The electrode showed a stable response towards H₂O₂ after electrochemical activation. Effects of flow rate, operating potential, concentration, injection volume and interferences were investigated. A linear response towards H₂O₂ from 5 μg.l^?1 to 450 mg.l^?1 and a detection limit (3 signal-to-noise ratio) of 4.7 μg.l^?1 was found. The method was employed for the determination of H₂O₂ in rain water samples.     

碳糊电极法测定普鲁卡因注射液中普鲁卡因的含量

制备了一种以普鲁卡因与单质碘形成的缔合物为电活性物的全固态碳糊普鲁卡因电极,利用该电极对普鲁卡因的响应测定普鲁卡因注射液中普鲁卡因的含量。电极的线性响应范围为3．5×10^-5～0．1mol／L,线性回归方程为E=57．01gc＋102．2,相关系数r=0．999,检出限为2．5×10^-5mol／L。盐酸普鲁卡因的回收率在96．1％～104.3％之间,测定结果的相对标准偏差为1．86％-2.30％（n=5）。该电极响应迅速,重现性好。用该电极测定了盐酸普鲁卡因注射液中普鲁卡因的含量,测定结果与药典法测定结果相符。     

聚酰胺修饰碳糊电极测定槲皮素的研究

用聚酰胺修饰碳糊电极在ｐＨ３６０的Ｂｒｉｔｏｎ－Ｒｏｂｉｎｓｏｎ缓冲溶液中，将槲皮素开路富集一定时间后，从０４５Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ）向阴极化扫描至－０５５Ｖ获得Ｉ－Ｅ曲线。槲皮素的峰电位为０１８Ｖ。峰电流与槲皮素浓度在１０～４００μｍｏｌ／Ｌ范围内呈良好的线性关系。所拟定方法用于芦丁水解产物测定，结果满意。     

A Novel Modified Carbon Paste Electrode for Potentiometric Determination of Mercury(II) Ion

A new modified carbon paste electrode (CPE) based on a recently synthesized ligand of Ethyl‐2‐(benzoylamino)‐3‐(2‐hydroxy‐4‐methoxyphenyl)‐2‐propenoate (EBHMP) as a suitable carrier for Hg²⁺ ion was described. The electrode exhibit a super Nernstian slope of 48.5±1.0 mV per decade for Hg²⁺ ion over a wide concentration range from 3.0×10^?7–3.1×10^?2 M. The lower detection limits are 1.0×10^?7 M Hg²⁺. The electrode has a fast response time (ca. 5 s), a satisfactory reproducibility and relatively long life time. The proposed sensor shows a fairly good selectivity toward Hg²⁺ ion in comparison to other common cations. The potentiometric responses are independent of the pH of the test solution in the pH range 1.0–4.0. The proposed electrode was used as an indicator electrode in potentiometric titration of mercuric ion with standard solution of EDTA. The direct determination of mercury in spiked wastewater and an amalgam sample gave results that compare favorably with those obtained by the cold vapor atomic absorption spectrometric method.     

碳糊电极阴极吸附伏安法测定橙皮甙

在0.4mol/L的NH4Cl-NH3(pH9.0)缓冲液中,使用JP-303极谱分析仪,橙皮甙在碳糊电极(CPE)上有一灵敏的吸附伏安还原峰,峰电位为-1.2V(vs.SCE).该还原峰的二阶导数峰电流与橙皮甙的浓度在2.0×10-8～1.0×10-6mol/L(富集90s)范围内成良好的线性关系,相关系数为0.9963,检出限为1.0×10-8mol/L(S/N=3,富集110s).探讨了橙皮甙在碳糊电极上的伏安性质和电极反应机理,并且成功应用于中草药桔皮中橙皮甙含量的测定.     

Differential Pulse Adsorptive Stripping Voltammetric Determination of Chlorpyrifos at a Sepiolite Modified Carbon Paste Electrode

Abstract

An adsorptive stripping voltammetric (AdSV) method for the determination of organophosphorus insecticide chlorpyrifos at a bare carbon paste electrode (CPE) and clay modified carbon paste electrode (CMCPE) was developed. A systematic study of various experimental conditions, such as the pH, accumulation variables and composition of a modifier on the adsorptive stripping response, were examined by using differential pulse voltammetry. A significant improvement was observed in the sensitivity by using the present method with CMCPE. When CMCPE was used, a linear response was obtained over the concentration range 0.0001–2.0 ppm with lower detection limit of 0.00008 ppm, at an accumulation time of 80 s. The interference from other herbicides and ions on the stripping signal of the compound was also evaluated. The described method was applied to estimate the chlorpyrifos in environmental samples.     

甲氧苄啶修饰玻碳电极安培法对过氧化氢的测定

在0.1 mol·L~(-1) KNO_3底液中,研究了甲氧苄啶在玻碳电极上的电化学性质,发现在0.140、0.177 V处出现1对可逆的氧化还原峰.进一步用电化学沉积的方法将甲氧苄啶修饰在玻碳电极上,考察了各种实验条件对修饰电极性能的影响,并通过电子扫描显微镜和电化学阻抗谱对修饰电极的表面性质进行了表征,所制得的修饰电极对过氧化氢的还原有很好的催化作用.在-0.3 V的工作电位下,用计时安培法对过氧化氢进行了测定,过氧化氢的浓度在1.96×10~(-5) ～1.10×10~(-3) mol·L~(-1)范围内与响应电流呈线性关系,检出限为4.0 μmol·L~(-1).该修饰电极制作简单、使用寿命长,实际试样的回收率为97% ～104%.     

Carbon Paste Electrode Bulk-Modified with the Conducting Polymer Poly(1,8-Diaminonaphthalene): Application to Lead Determination

Carbon paste electrodes modified with conducting polymers for sensitive and selective determination of lead are presented. A novel method for generating a reproducible polymer-coated electrode surface is developed. We prove that 1,8-diaminonaphthalene (1,8-DAN) mixed with a carbon paste electrode leads to a conducting polymer in acidic medium while, in the same medium, this polymer is known to be non-conducting on platinum electrode. The electrode behaviour of poly(1,8-DAN), electropolymerised into carbon paste, was investigated by cyclic voltammetry in the presence of the ferri-ferrocyanide couple.A carbon paste electrode modified with poly(1,8-DAN) was used to determine Pb²⁺ in aqueous solutions. Pb²⁺ ions were firstly complexed and then electrochemically deposited by a potential step to –0.9V. The accumulated lead after reduction was anodically stripped by differential pulse voltammetry. Different parameters, such as pH of the solution, preconcentration time, and electropolymerisation procedures were studied.For a preconcentration time of ten minutes, the calibration graph was linear from 40 to 2070ngmL^–1 with r²=0.998. The detection limit was found to be 30ngmL^–1, and the relative standard deviation was 6%.     

Determination of L-Ascorbic Acid by Adsorption Potentiometry with Carbon Paste Electrode

Abstract

This paper reports the potentiometric measurement of ascorbic acid in the solution of 0.10 mol/L NaOH-0.1 mol/L NaCl using carbon paste (the mixture of spectroscopic graphite powder and di-iso-octyl phthalate) electrode(room temperature 15°C), with the linear range 7.0 × 10^?7 × 4.0 × 10^?5mol/L, average response slope 95mV/decade and detection limit 1 × 10^?7mol/L. Phenol, sulfite, Mn²⁺ and so on pose no interference to the measurement of ascorbic acid. This method is characterized by fine selectivity, reproducibility and accuracy. The potential response behavior is caused chiefly by chemisorption of ascorbic acid to the surface of the carbon.

Each year yields a number of papers concerning the determination of ascorbic acid by various methods, including gas chromatographymass spectrometry¹, capillary electrophoresis², spectrophotometry³, voltammetry⁴, titrimetric method⁵, biosensor⁶ and so on, Each method has its merits and defects in analyzing different samples. M. Petersson⁷ worked out the potentiometric sensor for determining ascorbic acid by modifying monolayer of ferrocene upon the surface of half-oxidized platinum electrode with an average response slope 50±8.8mV/decade, but this sensor suffers from inadequate selectivity. In our study, carbon paste electrode (without ionophore) is applied in the determination of ascorbic acid by potentiometry with an average response slope 95mV/decade. This method displays fine selectivity, accuracy, convenience and rapidity of determination.     

碳糊电极阳极吸附伏安法测定环丙沙星

报道了用碳糊电极阳极吸附伏安法测定环丙沙星的新方法.在 0. 40mol/L的NH4Ac HAc(pH4. 30)缓冲液中,使用JP 303极谱分析仪,环丙沙星在碳糊电极 (CPE)上有一灵敏的吸附伏安氧化峰,峰电位为1. 12V(vs.SCE).该氧化峰的二阶导数峰电流与环丙沙星的浓度在 8. 0×10-9 ~8. 0×10-7 mol/L(富集 90s)范围内成良好的线性关系,相关系数为 0. 998 8,检出限为 4. 0×10-9 mol/L(S/N=3,富集 110s).探讨了环丙沙星在碳糊电极上的伏安性质和电极反应机理,并且成功应用于人体尿样中环丙沙星含量的测定.加入回收实验,回收率在95. 5%至 103. 9%之间.     

醇脱氢酶电极的研制

通过化学交联法将醇脱氢酶(ADH)固定在玻碳电极表面(Φ=5mm),使用N-甲基吩嗪甲基疏酸盐(PMS)和铁氰化钾为介体、间接测定酶促反应中生成的还原辅酶Ⅰ(NADH)。工作电位+300mv(vs.SCE)乙醇测定的线性范围为0.05～1.0mmol/L,响应时间小于20s。如果电极每天测定30次,可以使用两周。并对电极的选择性进行了讨论。     

Carbon Paste Electrode Modified with Biochar for Sensitive Electrochemical Determination of Paraquat

The present work reports for the first time the determination of paraquat (PQ²⁺) by Differential Pulse Adsorptive Stripping Voltammetry (DPAdSV) using a carbon paste electrode modified (CPME) with biochar obtained from castor oil cake at different temperatures (200–600 °C). The best voltammetric response was verified using biochar yielded at 400 °C (CPME‐BC400). Linear dynamic range (LDR) for PQ²⁺ concentrations between 3.0×10^?8 and 1.0×10^?6 mol L^?1 and a limit of detection (LOD) of 7.5×10^?9 mol L^?1 were verified. The method was successfully applied for PQ²⁺ quantification in spiked samples of natural water and coconut water.     

固体石蜡碳糊硅钼酸电极的研制及应用

将固体石蜡作粘合剂的碳糊电极在１０＾－４ｍｏｌ／Ｌ硅钼杂多酸溶液中活化后，其表面形成了杂多酸薄膜。电极对浓度为２．０×１０＾－５￣１．０×１０＾－２ｍｏｌ／Ｌ范围的硅钼杂多酸有所斯特响应；斜率为２９．０ｍＶ，从而可间接测定硅。该电极选择性、稳定性较好，响应快，已用于矿泉水样中偏硅酸含量测定。     

琥乙红霉素在碳糊电极上的电化学测定方法

以碳糊电极为工作电极,采用循环伏安（CV）法和示差脉冲伏安（DPV）法研究了琥乙红霉素（EEs）在电极上的电化学行为,建立了一种测定EEs的电化学新方法。 研究结果表明,在0.1 mol/L磷酸盐（pH=8.0）的缓冲液中,EEs在0.83和0.97 V(vs.SCE）处出现2个氧化峰。 用计时安培法(I-t)对EEs进行定量分析,峰电流Ip与琥乙红霉素的浓度分别在2.0×10-7~2.8×10-6 mol/L和2.8×10-6~3.1×10-5 mol/L范围内呈良好的线性关系检出限（S/N=3）为1.0×10-7 mol/L。 采用标准加入法测得回收率为950%～988%,RSD为3.4%(n=3)。 该方法具有较高的选择性和灵敏度,可用于药剂中EEs含量的测定,结果令人满意。     

碳糊电极和化学修饰碳糊电极的制备及性能综述

碳糊电极在电化学研究中起着非常重要的作用．从电极材料选用和修饰剂选择方面综述了碳糊电极和化学修饰碳糊电极制备的几种方法,分析了碳糊电极和化学修饰碳糊电极制备技术存在的主要问题及其原因,评价了碳糊电极和化学修饰碳糊电极的表征技术、性能以及影响电极性能的因素．概括了近年来本课题组在碳糊电极研究中的一些结果．