银、L-半胱氨酸修饰电极同时测定多巴胺和抗坏血酸

采用电聚合的方法将银、L-半胱氨酸先后修饰到电极表面,制备了银、L-半胱氨酸修饰电极fPLC／Ag／GCE）。研究了多巴胺和抗坏血酸在该修饰电极上的电化学行为,构建的电极可实现对多巴胺和抗坏血酸的同时检测。实验表明：在扫速为120mV／s,pH=3．0的磷酸盐缓冲溶液（PBS）中,多巴胺产生一对氧化还原峰,其氧化峰和还原峰的电位分别为0．447V和0．409V;而抗坏血酸只产生一个明显的氧化峰,其峰电位为0．238V。多巴胺和抗坏血酸的AEpa=0．209V,不需要分离便可对两者进行同时检测。在最佳条件下,测定多巴胺和抗坏血酸的线性范围分别为1．00×10-6～2．50×10-4mol/L和7．50×10-6--1．00×10-3mol／L．检出限分别为5．0×10-7mol／L和2．5×10-6mol／L。该方法可用于多巴胺和抗坏血酸的同时测定。     

基于碳纳米管修饰金电极的多巴胺电化学传感器

利用偶氮胭脂红B（ACB）对多壁碳纳米管（MWNTs）进行非共价修饰,使其具有水分散性,将MWNTs-ACB水分散液滴涂于金电极表面并置于红外灯下烤干,即制得多巴胺（DA）电化学传感器。伏安研究表明：MWNTs—ACB膜对生物小分子DA的电化学氧化具有良好的催化作用。最优的检测条件下,DA的检测线性范围为：1．0×10-6～1．0×10-mol／L,检出限低至5．0×10-7mol／L（S／N=3）。对传感器的性能进行了考察,结果表明：该DA传感器具有良好的稳定性和重现性,灵敏度高,选择性好。将传感器应用于注射液中DA含量的测定,结果令人满意。     

Multi-walled carbon nanotubes with poly(methylene blue) composite film for the enhancement and separation of electroanalytical responses of catecholamine and ascorbic acid

A novel conductive composite film containing multi-walled carbon nanotubes (MWCNTs) with poly(methylene blue) (PMB) has been synthesized on glassy carbon electrode (GCE), gold and indium tin oxide electrodes by potentiostatic methods. The presence of MWCNTs in the composite film enhance the surface coverage concentration (Γ) of PMB, increased the electron transfer rate constant (Ks) by 44.53% and decreased the degradation of PMB during the cycling. The composite film exhibits a promising higher electrocatalytic activity towards the oxidation of ascorbic acid (AA), epinephrine (EP) and dopamine (DA) present in pH 7.4 aqueous solution. The presence of PMB in the composite film enhances the functional properties and overall increase in the sensitivity of the composite film modified electrodes. Both, the cyclic voltammetry (CV) and square wave voltammetry (SWV) have been used for the measurement of electroanalytical properties of analytes by means of composite film modified electrodes. In CV, well-separated voltammetric peaks have been obtained at the composite film modified GCEs for AA–EP and AA–DA mixture with a peak separation of 144.36 and 164.00 mV, respectively. The detection limit values obtained are equivalent to the concentrations found in physiological conditions. Similar sensitivity values have been observed in CV and semi-derivative SWV. Further, the electrochemical quartz crystal microbalance and scanning electron microscopy have been used to reveal the enhancements in functional properties and surface morphology of the composite film.     

PVP/Pd/IrO2电化学修饰电极的研究及其应用

本文研制了一种新型的 PVP/Pd/IrO_2电化学修饰电极。在 Pt 电极表面先后修饰 PVP(Poly VinylPyridine)及 Pd/IrO_2,该修饰电极对 HSO_3~-有良好的催化氧化作用;同时,在恒电位+0.6V 条件下,以该修饰电极与 Ag/AgCl 电极,Pt 对电极组成的气体传感器,对 SO_2也有良好的响应,预计在环境监测及环境保护等领域有应用前景。     

聚硫堇和磁性核／壳纳米粒子CoFe2O4／SiO2修饰电极对多巴胺的测定

制备了聚硫堇（PTh）-磁性核,壳纳米粒子CoFe2O4／SiO2修饰电极。研究了神经递质多巴胺（DA）在该修饰电极上的电化学行为。实验表明,PTh—CoFe2O4／SiO2复合膜修饰电极对DA的电催化作用优于PTh修饰电极。在pH7．5的PBS中,DA在该修饰电极上的CV曲线于-0．16V和-0．22V处出现一对灵敏的氧化还原峰,峰电流显著增加。差分脉冲伏安法（DPV）氧化峰电流ips与DA浓度在1．2×10^-7-3．6×10^-5mol／L范围内呈良好的线性关系,线性回归方程ips（μA）=5．307c（μmol／L）＋0．7891,r=0．9923,检出限为6．0×10^-8mol／L（S／N=3）。常见物质对DA的检测无干扰,DA注射液样品检测结果与中国药典2010版（二部）规定方法一致。     

Au—Ni／酪氨酸酶修饰生物传感器检定BPA

将镍金材料结合壳聚糖修饰于玻碳电极表面形成复合膜,酪氨酸酶（Tyr）借助NHS～EDC联酶法修饰于复合膜上,制备了一种新型的酪氨酸酶修饰电极。以循环伏安法和电化学阻抗谱实验研究了修饰电极的电化学性能。由于复合材料良好的生物相容性和高电导特性,联酶法保持了酶活性和稳定性,该传感器对双酚A（BPA）具有良好的电化学响应。在最佳实验条件下,该传感器对双酚A的检测范围为：4．0×10^-8～5．0×10^-6mol／L,检测限为1.0×10^-8mol／L（信噪比=3）。该传感器具有良好的性能,重现性,稳定性。     

多巴胺在聚邻氨基酚/Ni~(2+)修饰碳糊电极的伏安行为

应用循环伏安法在碳糊电极上电聚合形成聚邻氨基酚膜(P-OAP),以浸泡吸附法使膜吸入金属离子Ni2+,制成Ni2+/P-OAP/CPE电极.电极经NaOH活化后,对多巴胺的电氧化的催化特性良好.薄膜的厚度、薄膜中Ni2+的浓度、电极的活化时间以及缓冲溶液pH值均影响电极催化活性.多巴胺和抗坏血酸在膜电极上的氧化峰电位相差188 mV,可用于在大量抗坏血酸存在下对多巴胺的灵敏检测.     

基于PVN-GO复合膜的亚硝酸盐电化学传感器

通过简单可控的滴涂成膜和在线电聚合方法,将氧化石墨烯（GO）和聚香兰素（PVN）修饰到玻碳电极（GCE）表面,制备了PVN-GO复合膜修饰GCE,即亚硝酸盐（NO2-）电化学传感器.伏安研究表明：PVN-GO复合膜对NO2-的电化学氧化具有良好的催化作用.借助于扫描电镜技术和电化学交流阻抗谱（EIS）技术,对PVN-GO复合膜的表面形貌和电导性进行了表征.最优的检测条件下,NO2-的检测线性范围为2.0 ×10^-8～1.1 ×10^-2mol/L,检出限低至5.0 ×10^-9 mol/L（S/N =3）.对传感器的性能进行了考核,结果表明：该NO2-传感器具有良好的稳定性和重现性,灵敏度高,选择性好.将传感器应用于南湖水样中亚硝酸盐含量的测定,结果令人满意.     

基于二氧化锆纳米粒子固定乙酰胆碱酯酶的甲基对硫磷传感器

先在金电极表面电沉积二氧化锆纳米粒子并固定乙酰胆碱酯酶(AChE),将此电极浸入含有不同浓度的有机磷溶液中,根据电极在底物氯化乙酰巯基胆碱中电化学信号强度的大小来实现溶液中有机磷的定量检测.以甲基对硫磷为分析目标物,研究了传感器的主要响应特性、选择性及再生性能,考察了底物浓度、工作电位及溶液pH值对分析性能的影响.结果表明,该有机磷传感器在5.0×10-7～5.0×10-4 g/L浓度范围内对目标分析物有线性响应,检出限为1.0×10-7 g/L.该传感器灵敏度高,非特异性吸附小,再生性好,所用的二氧化锆纳米粒子层制备简单、操作方便,具有较大的应用潜力.     

Sensitive PAT gene sequence detection by nano-SiO2/p-aminothiophenol self-assembled films DNA electrochemical biosensor based on impedance measurement

Nano-SiO₂/p-aminothiophenol (PATP) film was fabricated by self-assembly and electrodeposition methods. The immobilization and hybridization of DNA on the nano-SiO₂/PATP film were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). EIS was applied to label-free detection of the target DNA according to the increase of the electron transfer resistance (R_et) of the electrode surface after the hybridization of the probe DNA with the target DNA. This DNA electrochemical biosensor showed its own performance of simplicity, good stability, fine selectivity and high sensitivity, and was successfully applied to the detection of the PAT gene sequences by a label-free EIS method. The dynamic detection range was from 1.0 × 10⁻¹¹ to 1.0 × 10⁻⁶ mol/L 20-base sequence of the PAT gene, with the detection limit of 1.5 × 10⁻¹² mol/L. This DNA sensor has a good ability of recognizing single- or double-base mismatched DNA sequence with the complementary DNA sequence.     

Selective voltammetric determination of electroactive neuromodulating species in biological samples using iron(II) phthalocyanine modified multi-wall carbon nanotubes paste electrode

Iron(II) phthalocyanine (FePc) modified multi-wall carbon nanotubes paste electrodes (MWCNTPEs) were used as voltammetric sensors to selectively detect dopamine (DA) in the presence of serotonin (5-HT). The electrochemical behavior of DA at the new modified electrode was investigated using CV. The enhanced current response of DA indicates that FePc modification of the MWCNTPE surface results in a high catalytic activity for the redox reaction of DA. Differential pulse voltammetry was applied in detection of DA and 5-HT at FePc-MWCNTPE. The method parameters were optimized. Detection limit of 2.05 × 10⁻⁷ M was obtained for DA by using the electrocatalytic oxidation signal corresponding to the Fe^II/Fe^III redox process. The separation between the peak potentials of DA and 5-HT is 170 mV which is large enough for the simultaneously, selective determination of the two chemical species in their mixtures. There was no electrochemical response for ascorbic acid (AA) added in the sample. The monoamine neurotransmitter measuring method has been tested in analyzing deproteinized serum samples.     

基于铂纳米颗粒沉积多孔金膜的甲醛传感器

在多孔金膜表面电沉积铂纳米颗粒,制备了多孔金膜／铂纳米颗粒修饰电极。其中多孔金膜是在恒电位氧化后再在抗坏血酸溶液中还原制得的。利用循环伏安法（CV）对甲醛在此传感界面上的电化学行为进行了研究,结果表明,在酸性条件下,该传感器对甲醛表现出较好的电催化性能。在优化条件下,甲醛的峰电流与浓度在1×10^-5mol／L到1×10^-3mol／L范围内呈良好的线性关系,检出限5×10^-6mol／L。     

Graphene-polyaniline composite film modified electrode for voltammetric determination of 4-aminophenol

An electrochemical sensor based on graphene-polyaniline (GR-PANI) nanocomposite for voltammetric determination of 4-aminophenol (4-AP) is presented. The electrochemical behavior of 4-AP at the GR-PANI composite film modified glassy carbon electrode (GCE) was investigated by cyclic voltammetry. 4-AP exhibits enhanced voltammetric response at GR-PANI modified GCE. This electrochemical sensor shows a favorable analytical performance for 4-AP detection with a detection limit of 6.5 × 10⁻⁸ M and high sensitivity of 604.2 μA mM⁻¹. Moreover, 4-AP and paracetamol can be detected simultaneously without interference of each other in a large dynamic range.     

聚吡咯掺杂苯磺酸钠葡萄糖生物传感器

采用电化学聚合技术,用掺杂苯磺酸钠的聚吡咯（PPy）导电薄膜修饰铅笔芯电极,在修饰电极表面吸附葡萄糖氧化酶制备了葡萄糖生物传感器.研究了苯磺酸钠掺杂对PPy薄膜形貌、葡萄糖传感器性能的影响.实验结果表明：掺杂苯磺酸钠能够改变PPy形貌、极大提高其导电性.优化条件下该生物传感器抗干扰能力强、稳定性好,响应电流和葡萄糖浓度在0～0.7 mmol/L范围内有良好的线性相关度（R=0.9976）,灵敏度为26.10 μA/mmol/L,平均响应时间约为6.5s,检测下限为47.2 μmol/L.     

Noble metal dispersed multiwalled carbon nanotubes immobilized ss-DNA for selective detection of dopamine

A hybrid nanocomposite consisting of Pt nanoparticles decorated functionalized multiwalled carbon nanotubes (f-MWNT) immobilized with single strand-DNA (ss-DNA) has been devised for the selective detection of dopamine (DA). AFM and TEM analyses show that wrapping of ss-DNA over Pt/f-MWNT reduces the aggregation of the nanotubes arising from van der Waals interaction. In addition to serving as a noncovalent dispersion agent, ss-DNA facilitated electron transfer towards dopamine, as analyzed by cyclic voltammetric studies (CV) and amperometry. The sequence dependency of ss-DNA for DA detection has been analyzed using AC and GT ss-DNA. The hybrid nanocomposite biosensor consisting of AC/ss-DNA exhibits linearity of detection upto ∼315 μM, with a detection limit 0.8 μM towards dopamine. The best sensing performance with linearity of ∼800 μM and detection limit ∼0.45 μM has been obtained with GT/ss-DNA immobilized Pt/f-MWNT sensor. Further, the nafion coated ss-DNA wrapped Pt/f-MWNT immobilized biosensor exhibits good stability, fast response time (<3 s) and selective detection of DA in the presence of ascorbic acid and uric acid.     

Biocompatible hybrid film of β-cyclodextrin and ionic liquids: A novel platform for electrochemical biosensing

A novel electrochemical biosensing platform was developed based on the modification of biocompatible hybrid film of β-cyclodextrin (β-CD) and ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF₄) onto glass carbon electrode (GCE). Then an unmediated biosensor was successfully prepared by immobilizing the horseradish peroxidase (HRP) into the β-CD/ILs composite film. β-CD could provide a biocompatible microenvironment for HRP, and ILs could accelerate the electron transfer between HRP and the electrode. Results showed that the HRP entrapped in the β-CD/ILs film could maintain its native structure and the direct electrochemistry of HRP were facilely achieved. A couple of well-defined redox peaks of HRP were observed at about −0.32 V (vs. SCE), corresponding to the protein heme Fe(III)/Fe(II) redox couples. The electrocatalysis of this biosensor to both quercetin and hydrogen peroxide was characterized. The biosensor exhibited a low operating potential (−0.05 V vs. SCE), fast amperometric response, high sensitivity, good selectivity and sub-micromolar limit of detection.     

一次性免疫传感器快速检测阪崎肠杆菌的研究

为改善基于多壁碳纳米管/ Nafion生物传感器电化学信号及储存稳定性,采用[BMIM] PF6/Nafion复合物将辣根过氧化物酶标抗体包埋固定于MWCNT/Nafion修饰的丝网印刷碳电极上,构建了一种新的免疫传感器.用原子力显微镜表征电极各层修饰后的表面形态,用循环伏安法(CV)和交流阻抗法(EIS)考察修饰电极...     

离子液体修饰碳糊电极方波伏安法测定氨氯地平

研究了氨氯地平(Amlodipine besylate,Aml)在离子液体(1-Benzyl-3-Methylimidazole,[BnMIM]PF6)修饰碳糊电极([BnMIM]PF6/CPE)上的电化学行为和电化学动力学性质,并用循环伏安法(CV)及计时电流法(CA)测得Aml在[BnMIM]PF6/CPE上的电极反应动力学参数。实验结果表明,Aml在[BnMIM]PF6/CPE上发生了受吸附控制的不可逆电化学氧化过程。用方波伏安法(SWV)考察了Aml氧化峰电流与其浓度在1.2×10-6~1.0×10-3mol/L范围内呈良好的线性关系,检出限(3S/N)3.3×10-7 mol/L,RSD1.3%~3.4%之间,加样回收率98.2%~103%。     

A glucose oxidase immobilization platform for glucose biosensor using ZnO hollow nanospheres

A good route (template-directed synthetic route) for the fabrication of ZnO hollow nanospheres (ZnO-HNSPs) was proposed. ZnO hollow nanosphere is a wonderful platform to immobilize glucose oxidase for glucose biosensor owing to the high specific surface area and high isoelectric point (IEP). Along with nafion and glucose oxidase (GOD), a glucose sensor was designed. Nafion/ZnO-HNSPs/GOD/GCE displays higher catalytic activity toward the glucose oxidation than Nafion/ZnO nano-Flowers/GOD/GCE. Linear response was obtained over a concentration range from 5.0 × 10⁻³ mM to 13.15 mM with a detection limit of 1.0 μM (S/N = 3), and the sensitivity was 65.82 μA/(mM cm²). Satisfyingly, the Nafion/ZnO-HNSPs/GOD/GCE could effectively avoid the interferences from the common interfering species such as uric acid (UA), ascorbic acid (AA), dopamine (DA) and fructose. The Nafion/ZnO-HNSPs/GOD modified electrode allows high sensitivity, excellently selective, stable, and fast amperometric sensing of glucose and thus is promising for the future development of glucose sensors.     

基于核酸适体和纳米材料构建电化学生物传感器用于多巴胺的检测

该文探究了一种基于核酸适体和纳米金包四氧化三铁（Au@Fe,041纳米粒子所构建的新型电化学生物传感器用于多巴胺（DA）的检测。首先,在玻碳电极（GCE）表面电沉积一层纳米金（nano—Au）用于多巴胺适体（DBA）的固定。然后HT做为封闭剂以减少非特异性吸附。接着通过与DBA的特异性结合将DA固载于电极表面。在EDC／NHS作用下,生物素（Bio）的羧基与DA的氨基结合,最后通过生物素与亲和素特异性识别作用将含有电化学活性物质硫堇的纳米复合材料固定于电极表面,制得夹心型的适体传感器。在最优条件下．该传感器对0．001nmol／L-100nmol／LDA的检测具有良好的电流响应,检出限0．33pmol／LfS／N=31。该适体传感器具有操作简单、操作简便、选择性好、灵敏度高、检测范围广、检出限低的优点。