共查询到19条相似文献,搜索用时 203 毫秒
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运用循环伏安法、线性扫描伏安法及示差脉冲伏安法等测试技术研究了诺氟沙星在多壁碳纳米管修饰玻碳电极上的电化学行为,建立了一种直接测定诺氟沙星的电化学分析方法.结果表明,与裸玻碳电极相比,多壁碳纳米管修饰电极能显著提高诺氟沙星的氧化峰电流.在优化的实验条件下,氧化峰电流与诺氟沙星浓度在1.0×10-7~1.0×10-6mol/L和1.0×10-6~2.5×10-5 moL/L范围呈现良好的线性关系,检出限为3.0×10-8mol/L对1.0×10-5mol/L诺氟沙星溶液平行测定10次的RSD为4.1%.测定了诺氟沙星胶囊中诺氟沙星的含量,结果满意. 相似文献
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《广州化工》2016,(12)
采用滴涂法在玻碳电极上修饰氧化石墨烯及多壁碳纳米管,通过电化学还原方法制备石墨烯/多壁碳纳米管复合材料及相应修饰电极(ERGO/MWCNTs/GCE)。运用循环伏安法研究多巴胺(DA)在修饰电极上的电化学行为。研究表明:与裸玻碳电极相比,多巴胺在修饰电极上氧化峰与还原峰电位差为70 m V,峰电流显著提高,表明该电极对多巴胺具有较好的催化氧化作用。高浓度抗坏血酸的存在不影响多巴胺的测定。在优化实验条件下,多巴胺在4.8×10~(-7)~1.1×10~(-5)mol/L和1.1×10~(-5)~2.93×10~(-4)mol/L范围内呈良好的线性关系,检出限为8.7×10~(-8)mol/L,RSD为4.3%。 相似文献
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制备了石墨烯(GO)与碳纳米管(MWNT)复合材料修饰玻碳电极,在浓度为0.1 mol/L、p H为5.5的磷酸缓冲溶液(PBS)中,探讨了抗坏血酸(AA)和亚硝酸根(NO-2)在石墨烯与碳纳米管复合材(GO-MWCNTs)料修饰玻碳电极上的电化学行为。结果表明,抗坏血酸和亚硝酸根在该修饰电极上氧化电流可得到明显增强。利用计时电流法测定抗坏血酸与亚硝酸根,抗坏血酸和亚硝酸根氧化电流呈线性关系的浓度范围分别为3.00×10-6~4.06×10-3mol/L和7.44×10-5~3.28×10-3mol/L。 相似文献
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利用电化学方法在玻碳电极表面聚合一层普鲁士蓝,制备普鲁士蓝修饰玻碳电极,运用循环伏安法研究了2,6-二甲基苯酚在该修饰电极上的电化学行为。结果表明,该修饰电极对2,6-二甲基苯酚显示出较好的电化学响应和电催化活性,在pH为4.0的HAc-NaAc缓冲溶液中,2,6-二甲基苯酚浓度与其峰电流在2.0×10-5~1.0×10-2 mol/L范围内呈现良好的线性关系。 相似文献
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以多壁碳纳米管为原料制备氧化石墨烯纳米带(GONRs),通过红外光谱、紫外-可见吸收光谱和拉曼光谱对其进行表征。将制备好的GONRs脉冲电沉积到玻碳电极(GCE)表面制备修饰电极(GONRs/GCE),研究了盐酸四环素(TC)在GONRs/GCE上的电化学行为。结果表明,与裸玻碳电极相比,GONRs/GCE对TC有更高的电催化活性。TC在GONRs/GCE上发生受吸附控制的不可逆氧化反应,且在pH 3.0的柠檬酸-柠檬酸钠缓冲溶液中氧化峰电流最高。优化条件下,TC的氧化峰电流与浓度线性相关,线性范围为4.0×10~(-7)~1.0×10~(-4) mol/L,最低检测限为2.0×10~(-7) mol/L(S/N=3)。将该电极用于河水样品中TC的检测,加标回收率为97.2%~104.1%。 相似文献
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以羧基化碳纳米管(CNT-COOH)溶液作为支持电解质,采用多电位阶跃电沉积方法将CNTs和纳米金同步直接沉积到玻碳电极表面,制备了对邻苯二酚(CAT)具有很高的电催化氧化作用的纳米金-碳纳米管修饰电极(Au/CNTs/GCE),其催化效果强于单独的金纳米粒子或碳纳米管修饰电极。通过优化沉积时间、pH和扫速对修饰电极的影响,并考察了在最佳条件下CAT在Au/CNTs/GCE修饰电极上的电化学行为,发现CAT在该修饰电极上发生可逆的氧化还原反应,响应电流与浓度在4.0×10-6~8.0×10-5mol/L和1.0×10-4~1.0×10-3mol/L范围内呈线性关系,相关系数分别为0.9996和0.9985,检出限为4.5×10-7mol/L(S/N)。 相似文献
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A modified carbon-paste electrode (CPE) is prepared by incorporating thionine-nafion supported on multi-walled carbon nanotube (MWCNT). The electrochemical behavior of dopamine (DA) and ascorbic acid (AA) on the surface of the modified electrode is investigated by cyclic voltammetry (CV). The results show that thionine effectively immobilized in the matrix of the paste by using an appropriate mixture of nafion/MWCNT under the ultrasonic condition. On the other hand, presence of nafion enhances the stability of the thionine supported by MWCNT in the composite electrode and improves the reproducibility of the surface of the modified electrode under renewing process by polishing. The results of cyclic and differential pulse voltammetric investigations show that the modified electrode possesses an efficient electrocatalytic activity for the electrochemical oxidation of DA and AA and a peak potential separation nearly 379 mV is resulted for two compounds. The prepared modified electrode does not show any considerable response toward the electro-oxidation of sulfhydryl compounds, such as, cysteine, penicillamine and glutathione, revealing a good selectivity for voltammetric response to AA and DA in clinical and pharmaceutical preparations. The effective electrocatalytic property, excellent peak resolution and ability for masking the voltammetric responses of the other biologically reducing agents, make the modified electrode suitable for simultaneous and sensitive voltammetric detection of sub-micromolar amounts of AA and DA. 相似文献
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Kan Kan Tingliang Xia Ying Yang Hongmei Bi Honggang Fu Keying Shi 《Journal of Applied Electrochemistry》2010,40(3):593-599
The multi-walled carbon nanotube (MWCNT) was functionalized with hydroxyl, carboxyl and amido groups on the surface. Electrocatalytic
oxidation of nitric oxide (NO) at the MWCNT modified electrodes was investigated. It was found that the MWCNT modified electrode
could speed up greatly the electron transfer rate compared with the glass carbon electrode, and there was an adsorptive step
for the oxidation of NO at the MWCNT modified electrode. The activation energy of NO electrooxidation reaction at modified
electrode of MWCNT treated by alkali and mixed acids (MWCNT-OH–COOH) decreased, and current density was almost two times that
of the electrode modified with alkali treated MWCNT. The modified electrodes of MWCNT amidated with the aliphatic amines decreased
the activation energy of NO oxidation compared with MWCNT modified electrode, but the reaction rate of amidated MWCNT electrodes
decreased because of the steric effect. The results demonstrated that MWCNT-OH–COOH modified electrode is the best for NO
electrocatalytic oxidation. 相似文献
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Mamta Latwal Prakash Chandra Shah Raj Ali 《Journal of Applied Electrochemistry》2014,44(10):1127-1134
Nanostructured copper hexacyanidoferrate has been synthesized and characterized using elemental analysis, atomic absorption spectroscopy, thermal and infrared spectral studies. The transmission electron microscopic studies of the synthesized material showed that it consisted of irregular oval and rod shaped particles with a size range 70–100 nm. Nanostructured copper hexacyanidoferrate modified glassy carbon electrode was characterized by cyclic voltammetery and nanostructured copper hexacyanidoferrate–carbon nanotube composite material modified glassy carbon electrode has been used for electrocatalytic oxidation of salbutamol. The electrode modified with composite material was found to reduce the peak potential of oxidation of salbutamol by nearly 90 mV. 相似文献
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A selective determination of levodopa (LD) in the presence of ascorbic acid (AA) and uric acid (UA) has been investigated at a glassy carbon electrode modified with reduced graphene oxide (rGO). The graphene oxide was synthesized chemically by Hummers method and characterized by energy-filtered transmission electron microscopy (EF-TEM). The reduced graphene oxide modified glassy carbon electrode (rGO/GCE) showed excellent electrochemical performance in the simultaneous electrochemical detection of LD, AA, and UA due to the unique properties of graphene, such as large surface area, facile electronic transport and high electrocatalytic activity. The redox characteristics of rGO/GCE were investigated with cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Well-resolved oxidation peak potentials, corresponding to the oxidation of AA, LD, and UA, were observed from their mixture solution at 0.098, 0.285, and 0.423 V, respectively. The rGO/GCE showed that LD can be detected without the interference of AA and UA. Under the optimized conditions, the oxidation peak current of LD is linear with the concentration of LD from 2.0 to 100 μM with the detection limit of 1.13 μM (S/N = 3). The present electrode system was also successfully applied to direct determination of LD in commercially available tablets and urine samples. 相似文献
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This paper reports the selective determination of norepinephrine (NEP) in the presence of very important interferences, ascorbic acid (AA) and uric acid (UA) using electropolymerized film of 2-amino-1,3,4-thiadiazole (p-ATD) modified glassy carbon (GC) electrode in 0.20 M phosphate buffer solution (pH 5.0). The bare GC electrode does not separate the voltammetric signals of AA, NEP and UA. However, p-ATD modified GC electrode not only resolved the voltammetric signals of AA, NEP and UA with potential differences of 150 and 130 mV between AA–NEP and NEP–UA, respectively but also dramatically enhanced the oxidation peak currents of them when compared to bare GC electrode. The modified electrode showed an excellent selectivity towards NEP even in the presence of 100-fold excess of AA and UA. The amperometric current was linearly increased from 40 nM to 25 μM for NEP and the lowest detection limit was found to be 0.17 nM (S/N = 3). The practical application of the modified electrode was demonstrated by determining NEP in norepinephrine hydrochloride injection. 相似文献
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Multi walled carbon nanotube modified carbon-ceramic electrode (MWCNT/CCE) was employed for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The MWCNT/CCE displayed very good electrochemical catalytic activities with respect to CCE. The oxidation over-potentials of AA, DA and UA decreased dramatically, and their oxidation peak currents increased significantly at MWCNT/CCE compared to those obtained at the bare CCE. Differential pulse voltammetry was used for the simultaneous determination of AA, DA and UA in their ternary mixture. The peak separation between AA and DA, and DA and UA was large up to 205 and 160 mV, respectively. The calibration curves for AA, DA and UA were obtained in the range of 15.00-800.00, 0.50-100.00, and 0.55-90.00 μM, respectively. The detection limits (S/N = 3) were 7.71, 0.31, and 0.42 μM for AA, DA and UA, respectively.The present method was applied to the determination of AA, DA and UA in human serum and some commercial pharmaceutical samples, using standard adding method and the results were quite promising. 相似文献
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The behaviour of a poly (aniline boronic acid) (PABA) modified glassy carbon electrode (GCE) for the detection of dopamine (DA) in the presence of excess of ascorbic acid (AA) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques is investigated. On bare GCE, both DA and AA are oxidized at ~0.16 V, whereas on PABA modified GCE they are oxidized at 0.2 and 0.054 V, respectively. Though PABA favours DA oxidation through ester formation with boronic acid motif, the AA oxidation is also promoted by polyaniline backbone through the involvement of AA in the redox of polyaniline. Since both DA and AA undergo oxidation at closely spaced potentials at a PABA electrode, Nafion®-incorporation into the PABA film was examined for selective determination of DA in the presence of AA. The selectivity was due to accumulation of DA on the electrode surface through ester formation with the boronic acid group and suppression of AA oxidative current through charge discrimination by Nafion. 相似文献
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This paper describes the electrocatalytic oxidation of ascorbic acid (AA) in phosphate buffer solution by the immobilized citrate capped gold nanoparticles (AuNPs) on 1,6-hexanedithiol (HDT) modified Au electrode. X-ray photoelectron spectrum (XPS) of HDT suggests that it forms a monolayer on Au surface through one of the two SH groups and the other SH group is pointing away from the electrode surface. The free SH groups of HDT were used to covalently attach colloidal AuNPs. The covalent attachment of AuNPs on HDT monolayer was confirmed from the observed characteristic carboxylate ion stretching modes of citrate attached with AuNPs in the infra-red reflection absorption spectrum (IRRAS) in addition to a higher reductive desorption charges obtained for AuNPs immobilized on HDT modified Au (Au/HDT/AuNPs) electrode in 0.1 M KOH when compared to HDT modified Au (Au/HDT) electrode. The electron transfer reaction of [Fe(CN)6]4−/3− was markedly hindered at the HDT modified Au (Au/HDT) electrode while it was restored with a peak separation of 74 mV after the immobilization of AuNPs on Au/HDT (Au/HDT/AuNPs) electrode indicating a good electronic communication between the immobilized AuNPs and the underlying bulk Au electrode through a HDT monolayer. The Cottrell slope obtained from the potential-step chronoamperometric measurements for the reduction of ferricyanide at Au/HDT/AuNPs was higher than that of bare Au electrode indicating the increased effective surface area of AuNPs modified electrode. The Au/HDT/AuNPs electrode exhibits excellent electrocatalytic activity towards the oxidation of ascorbic acid (AA) by enhancing the oxidation peak current to more than two times with a 210 mV negative shift in the oxidation potential when compared to a bare Au electrode. The standard heterogeneous electron transfer rate constant (ks) calculated for AA oxidation at Au/HDT/AuNPs electrode was 5.4 × 10−3 cm s−1. The oxidation peak of AA at Au/HDT/AuNPs electrode was highly stable upon repeated potential cycling. Linear calibration plot was obtained for AA over the concentration range of 1–110 μM with a correlation coefficient of 0.9950. The detection limit of AA was found to be 1 μM. The common physiological interferents such as glucose, oxalate ions and urea do not show any interference within the detection limit of AA. The selectivity of the AuNPs modified electrode was illustrated by the determination of AA in the presence of uric acid. 相似文献