电聚合修饰碳纤维电极及乳酸脱氢酶活性的测定

用电聚合方法将亚甲基绿 (MG)修饰在碳纤维电极 (直径 7μm)上 ,并用该修饰电极测定了乳酸脱氢酶 (LDH)活性。在烟酰胺腺嘌呤二核苷酸 (NAD+ )浓度为 6 .0× 10 - 4mol L ,乳酸浓度为 5 .0× 10 - 3mol/L的pH7.0NaOH KH2 PO4 缓冲介质中 ,电位恒定在 +0 .10V下 ,用电流法测定乳酸脱氢酶活性 ,线性范围为 15～ 2 4 0U/mL ,检测限为 10U/mL ,响应时间为 15s。该修饰微电极稳定性好、灵敏度高、测定干扰小     

聚苯胺修饰碳纤维针型复合微pH传感器

由电聚合法用聚苯胺修饰碳纤维电极作为ＰＨ敏感电极。把Ｋ３Ｆｅ（ＣＮ）６／Ｋ４Ｆｅ（ＣＮ）６体系填入医用注射针头内成为参比电极。把经聚苯胺修饰的碳纤维电极安置入该针型参比电极内构成复合针型微ｐＨ传感器。在ＰＨ ２～１２范围内，该传感器呈现超Ｎｅｒｎｓｔ响应，斜率为－７８ ｍＶ／ｐＨ；响应时间<１ｍｉｎ。该传感器成功地应用于在体ｐＨ测定以及水果内微区ｐＨ测定。     

Amperometric Biosensor for Hydrogen Peroxide Based on Electrodeposited Sub-micrometer Gold Modified Glassy Carbon Electrode

IntroductionAmperometricbiosensorofhydrogenperoxideisofpracticalimportancebecauseofitswideapplicationsinchemical,biological,clinical,environmentalandmanyotherfields.Forimprovementofsensor抯quality,vari-ouskindsofchemicalmodificationmethodshavebeendevelopedforreducingredoxoverpotentialsofH2O2atelectrodesurfaces,increasingthedetectionsensitivity,linearrange,stabilityandlivetime.Ithasbeenshownthattheuseofsub-micrometersizedmetalparticlessuchasPt-blackcansignificantlyimprovethequalityofthebiosens…     

酚类化合物在二氧化锡微粒修饰碳纤维电极上的氧化及检测

采用金属有机化学气相沉积技术制备了SnO2 修饰碳纤维微柱电极 ,讨论了电极的表面结构和稳定性 ,并利用循环伏安法分析了酚类化合物在电极上的电化学行为。该电极对酚类化合物有明显的电催化活性 ,并能防止酚类物质在碳纤维电极表面的电聚合。以 3 氯苯酚为测试物 ,其检测的线性浓度范围为 2× 10 -6～ 1.2× 10 -5mol/L     

硫辛酸修饰电化学活化碳纤维微电极选择性测定神经递质5—羟色胺

硫辛酸修饰电化学活化碳纤维微电极是一种新型的化学修饰碳纤维微电极。碳纤维微电极经适当的电化学方法活化后，对神经递质５－羟色胺（５－ＨＴ）的灵敏度高于其代谢物５－羟吲哚乙酸（５－ＨＩＡＡ），在此基础上，用硫辛酸修饰，显著地提高了电极对５－ＨＴ的响应灵敏度，其线性范围为１×１０＾－５ｍｏｌ／Ｌ，检测下限为５×１０＾－９ｍｏｌ／Ｌ，同时有效地抑制了电极对５－ＨＩＡＡ的响应，并且可完全消除尿酸的干扰     

Highly Sensitive Choline Oxidase Enzyme Inhibition Biosensor for Lead Ions Based on Multiwalled Carbon Nanotube Modified Glassy Carbon Electrodes

The determination of lead ions by inhibition of choline oxidase enzyme has been evaluated for the first time using an amperometric choline biosensor. Choline oxidase (ChOx) was immobilized on a glassy carbon electrode (GCE) modified with multiwalled carbon nanotubes (MWCNT) through cross‐linking with glutaraldehyde. In the presence of ChOx, choline was enzymatically oxidized into betaine at –0.3 V versus Ag/AgCl reference electrode, lead ion inhibition of enzyme activity causing a decrease in the choline oxidation current. The experimental conditions were optimised regarding applied potential, buffer pH, enzyme and substrate concentration and incubation time. Under the best conditions for measurement of the lowest concentrations of lead ions, the ChOx/MWCNT/GCE gave a linear response from 0.1 to 1.0 nM Pb²⁺ and a detection limit of 0.04 nM. The inhibition of ChOx by lead ions was also studied by electrochemical impedance spectroscopy, but had a narrower linear response range and low sensitivity. The inhibition biosensor exhibited high selectivity towards lead ions and was successfully applied to their determination in tap water samples.     

基于多孔碳固载离子液体修饰电极的叔丁基对苯二酚的检测研究

制备了多孔碳固载离子液体纳米材料修饰玻碳电极(GCE),用于抗氧化剂叔丁基对苯二酚(TBHQ)的检测研究。不同电极上的交流阻抗结果表明,经过多孔碳固载离子液体修饰后的玻碳电极阻抗显著减小。多孔碳固载离子液体修饰后电极的氧化峰电流为41.93μA,比修饰前增大约5.5倍,说明多孔碳固载离子液体可显著提高电极的导电性,促进电极表面的电子转移,提高检测灵敏度。用时间~电流曲线测得TBHQ的线性范围为1.00~120.00μg/mL,检出限为0.16μg/mL。     

溶胶-凝胶血红蛋白电化学传感器的研制

运用溶胶-凝胶技术将血红蛋白(Hb)固载于玻碳电极(GC)表面,制得Hb/Sol-Gel/GC修饰电极,找出了制备Hb/Sol-Gel/GC修饰电极的最佳实验条件,建立了一种测定过氧化氢的新的、灵敏的方法.同时对该电极与过氧化氢的作用机理进行了探讨.     

聚中性红修饰玻碳电极葡萄糖生物传感器

以中性红为电子媒介体,电聚合于Nafion修饰的玻碳电极表面,以戊二醛作交联剂固定葡萄糖氧化酶,最后覆盖一层Nafion膜防止酶流失,构建一种新型葡萄糖生物传感器.详细探讨了传感器的电化学性能及对葡萄糖的最佳响应条件.结果表明,30℃时,传感器在pH 7.0的PBS中对葡萄糖的线性响应范围为1.0×10-5~5.0×10-3mol.L-1.该传感器制作简单、性能优良,有潜在应用前景.     

Nafion修饰电化学活化碳纤维微电极测定去甲肾上腺素

本用自制的碳纤维微电极，经过适当的电化学预处理以后，测定神经递质去甲肾上腺素时，表现出较高的灵敏度，用Ｎａｆｉｏｎ修饰后，能有效地消除脑中去甲肾上腺素的主要干扰物抗坏血酸的干扰，线性范围５×１０＾－５－２×１０＾－４ｍｏｌ／Ｌ，检出下为２×１０＾－８ｍｏｌ／Ｌ，用这种微电极对注射液中的去甲肾上腺素进行测定，回收率在９７．２％－１０２．８５之间，可用于活体分析。     

Determination of 1‐Naphthol with Denatured DNA–Modified Pretreated Glassy Carbon Electrode

Abstract

A highly sensitive electrochemical biosensor for the detection of trace amount of 1‐naphthol was designed. Acid‐denatured DNA were immobilized onto the pretreated glassy carbon electrode (GCE(ox)) surface. Two well‐defined oxidation peaks were observed on the denatured DNA‐modified GCE(ox) at about +0.80 V and +1.10 V (vs. Ag/AgCl) in 0.10‐M acetate buffer (pH 5.0). The peak current of the guanine residue decreased with increasing concentration of 1‐naphthol. The optimum experimental conditions for the detection of 1‐naphthol were explored, and the calibration was linear for 1‐naphthol in the range of 1.0×10^?8?1.1×10^?6 M, with a correlation coefficient of 0.998. The limit of detection (LOD) was 5.0×10^?9 M (S/N=3).     

多壁碳纳米管修饰玻碳电极伏安法测定氯霉素

研究了氯霉素(CAP)在多壁碳纳米管修饰玻碳电极上的电化学行为.发现在pH=2.0的0.1 mol/LKCl-HCl底液中,CAP在该修饰电极上有一灵敏的还原峰(Ep=-0.36 V vs.Ag/AgCl),峰电流与CAP浓度成正比,线性范围为6.0×10-6~2.7×10-4mol/L,检测限达3.0×10-6mol/L.该方法灵敏、准确,用于模拟样品和实际样品的测定,结果满意.     

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。     

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。     

8—羟基喹啉合镁碳糊修饰电极的研究

本文研制了８－羟基喹啉合镁碳糊修饰电极，并研究了电极性能，实验发现，该修饰电极具有类化学传感器的特性，电极在一定条件下对Ｍｇ＾２＋离子有类能斯特响应，电极用于试样分析取得成功。     

纳米银掺杂炭气凝胶修饰电极对卤素离子的电化学响应

首次以新型的纳米银掺杂炭气凝胶为材料,制备了一种新型纳米银炭电极,并考察了该电极对卤素离子的电化学响应。在0.1 mol/L的KNO3中,用微分脉冲伏安法对含Cl-的溶液以及卤素离子共存时的溶液进行测定,结果表明:峰电流与Cl-浓度呈线性关系,线性范围为2.0×10-7-4.2×10-5mol/L;检出限为1.2×10-8mol/L。此外响应电流与Cl-、Br-、I-3种离子的总浓度在6.0×10-7-1.2×10-5mol/L范围内呈线性关系。结果表明,纳米银掺杂炭气凝胶修饰电极可望用于痕量卤素离子的测定。     

A Novel Sensor Based on Carbon Paste Electrode Modified with Polypyrrole/Multi-walled Carbon Nanotubes for the Electrochemical Detection of Cytostatic Drug Rapamycin

The electrocatalytic oxidation of rapamycin, one of the most studied immunosuppressant, cancer-preventing drug, is investigated for the first time on the surface of the modified carbon paste electrode prepared by incorporating multi-walled carbon nanotubes (MWCNTs) and conductive polymer pyrrole using differential pulse voltammetry (DPV). Rapamycin exhibited a well-defined oxidation peak at +1.1 V (versus Ag/AgCl) in Briton Robinson buffer solution with a pH 4.0. Effect of the most important experimental parameters was optimized and obtained signals are linear to the concentration of rapamycin in the range from 0.1 to 20 μM with 0.06 μM limit of detection. The repeatability is calculated as ±2 % and the reproducibility as ±5 %. The possible interfering compounds were tested showing negligible effect and the sensor was successfully applied for the determination of rapamycin in commercial pharmaceutical formulations with obtained recoveries in the range from 98 % to 102 %.     

Electrochemical Determination of Tannins Using Multiwall Carbon Nanotubes Modified Glassy Carbon Electrode

A novel chemically modified electrode is prepared on the basis of the attachment of multiwall carbon nanotubes (MWNTs) to the surface of a glassy carbon electrode (GCE) in the presence of a hydrophobic surfactant. The electrochemical behavior of tannins at the MWNTs-modified GCE is investigated. Tannins yield a well-defined oxidation at about 0.30 V (SCE) at the MWNTs-modified GCE. MWNT-film shows remarkable enhancement effect on the oxidation peak current of tannins. The experimental parameters are optimized, and a direct electrochemical method to detect tannins is proposed. The oxidation peak current is proportional to the concentration of tannins over the range from 4 × 10^–7 to 2 × 10^–4 M, and the detection limit is 1 × 10^–7 mol/l after 5 min of accumulation. The relative standard deviation of 6% for determination of 2 × 10^–6 mol/l tannins indicates excellent reproducibility. The analysis method is demonstrated by using tea and Chinese gall samples.     

碳纳米管修饰电极上沙丁胺醇电催化氧化研究

将多壁碳纳米管(MWNT)分散在疏水性表面活性剂双十六烷基磷酸(DHP)溶液中形成稳定、均相的分散液,然后制备多壁碳纳米管-DHP复合膜修饰玻碳电极(MWNT-DHP/GCE).应用方波伏安法研究了沙丁胺醇在修饰电极上的电化学行为,结果表明,碳纳米管复合膜修饰电极对沙丁胺醇的氧化有良好的电催化活性,其氧化反应为一电子一质子过程,氧化电位比裸玻碳电极负移40 mV,峰电流增加了4.5倍.在最佳测试条件下,氧化峰电流与沙丁胺醇浓度在8.3×10-7~3.3×10-6mol/L范围内呈良好线性关系,开路富集2min,检出限达1.8×10-7mol/L.该修饰电极具有良好的重现性、稳定性.     

多壁碳纳米管修饰电极对对苯二酚的电催化作用

研究了多壁纳米碳管修饰电极的制备及其对对苯二酚的电催化作用。讨论了支持电解质种类、酸度、修饰层厚度和扫速等因素对对苯二酚伏安响应的影响 ,获得了较为优化的实验条件。在 0 .1mol/L磷酸盐 (pH 6 .0 )缓冲溶液中 ,采用示差脉冲伏安法测定对苯二酚 ,其浓度在 5 .0× 1 0 -6～ 1 .1× 1 0 -3 mol/L范围内与其氧化峰电流呈良好的线性关系 ,检出限达 2 .7× 1 0 -6mol/L。共存的多种金属离子、抗坏血酸及等量的苯酚、邻苯二酚等不干扰测定。该电极用于模拟废水样中对苯二酚的测定 ,结果令人满意