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1.
Direct electrochemistry of DNA,guanine and adenine at a nanostructured film-modified electrode 总被引:5,自引:0,他引:5
A nanostructured film electrode, a multi-wall carbon nanotubes (MWNT)-modified glassy carbon electrode (GCE), is described for the simultaneous determination of guanine and adenine. The properties of the MWNT-modified GCE were investigated by scanning electron microscopy (SEM) and cyclic voltammetry. The oxidation peak currents of guanine and adenine increased significantly at the MWNT-modified GCE in contrast to those at the bare GCE. The experimental parameters were optimized and a direct electrochemical method for the simultaneous determination of guanine and adenine was proposed. Using the MWNT-modified GCE, a sensitive and direct electrochemical technique for the measurement of native DNA was also developed, and the value of (G+C)/(A+T) of HCl-digested DNA was detected. 相似文献
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《Electroanalysis》2005,17(10):901-905
A novel chemically modified electrode based on the chitosan‐multiwall carbon nanotube (MWNT) coated glassy carbon electrode (GCE) is described, which exhibited an attractive ability to determine uric acid (UA) and norepinephrine (NE) simultaneously. The responses of UA and NE merged into a large peak at a bare GCE, but yielded two well‐defined oxidation peaks at the chitosan‐MWNT modified GCE (MC/GCE). The experimental parameters were optimized, and a direct electrochemical method for the simultaneous determine for UA and NE is proposed. The MC/GCE showed good sensitivity, selectivity and stability. 相似文献
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Simple and sensitive electrochemical method for the determination of metronidazole, based on a nanostructured film coated glassy carbon electrode (GCE), is described. Multi-walled carbon nanotubes (MWNT) was dispersed into water in the presence of a hydrophobic surfactant to give very stable and homogeneous MWNT suspension, and a MWNT-film coated GCE was achieved via evaporating solvent. Metronidazole yields a well-defined reduction peak whose potential is −0.71 V at the MWNT-film coated GCE in pH 9.0 Britton-Robinson buffer. Compared with bare GCE, the MWNT-film modified GCE significantly enhances the reduction peak current of metronidazole. All the experimental parameters were optimized for the determination of metronidazole. The detection limit is 6×10−9 mol/l at 2 min accumulation. This method has been successfully used to determine metronidazole in the drugs. Furthermore, results obtained by the proposed method have been compared with spectrophotometric method. 相似文献
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多壁碳纳米管-Nafion化学修饰电极在高浓度抗坏血酸和尿酸体系中选择性测定多巴胺 总被引:18,自引:0,他引:18
多巴胺是人体内一种重要的神经传递物质 ,它参与许多生命过程[1] .因此 ,测定体内多巴胺的浓度十分重要 .多巴胺的电化学分析方法已有不少报道 [2 ,3 ] .然而 ,共存的抗坏血酸和尿酸的电化学性质与多巴胺相似 ,对多巴胺的测定会产生严重干扰 .因此建立一种选择性测定多巴胺的高灵敏度的分析方法就显得尤为重要 .碳纳米管是一种新型的纳米材料 [4 ] ,它的出现引起了广泛的研究兴趣 [5,6] .由于其性质稳定 ,不溶于水及一般的有机溶剂 ,因此限制了其在电分析方面的应用 .本文将多壁碳纳米管分散在 Nafion的无水乙醇中 ,得到了一种均匀的多壁碳… 相似文献
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Mixtures of gold-platinum nanoparticles (Au-PtNPs) are fabricated consecutively on a multi-walled carbon nanotubes (MWNT) coated glassy carbon electrode (GCE) by the electrodeposition method. The surface morphology and nature of the hybrid film (Au-PtNPs/MWCNT) deposited on glassy carbon electrodes is characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. The modified electrode is used as a new and sensitive electrochemical sensor for the voltammetric determination of cefotaxime (CFX). The electrochemical behavior of CFX is investigated on the surface of the modified electrode using linear sweep voltammetry (LSV). The results of voltammetric studies exhibited a considerable improvement in the oxidation peak current of CFX compared to glassy carbon electrodes individually coated with MWCNT or Au-PtNPs. Under the optimized conditions, the modified electrode showed a wide linear dynamic range of 0.004-10.0 μM with a detection limit of 1.0 nM for the voltammetric determination of CFX. The modified electrode was successfully applied for the accurate determination of trace amounts of CFX in pharmaceutical and clinical preparations. 相似文献
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A multiwalled carbon nanotubes (MWNT) modified glassy carbon electrode (GCE) coated with poly(orthanilic acid) (PABS) film
(PABS–MWNT/GCE) has been fabricated and used for simultaneous determination of dopamine (DA) and uric acid (UA) in the presence
of ascorbic acid (AA) by differential pulse voltammetry (DPV). Scanning electron microscopy, Fourier transform infrared spectra,
and electrochemical techniques have been used to characterize the surface morphology of the PABS–MWNT composite film and the
polymerization of ABS on electrode surface. In comparison with the bare GCE and the MWNT-modified GCE, the PABS–MWNT composite
film-modified GCE, which combines the advantages of MWNT and the self-doped PABS, exhibits good selectivity and sensitivity
for the simultaneous and selective determination of UA and DA in the presence of AA. Due to the different electrochemical
responses of AA, DA, and UA, PABS–MWNT/GCE can resolve the overlapped oxidation peak of DA and UA into two well-defined voltammetric
peaks with enhanced current responses using both cyclic voltammetry (CV) and DPV. The peak potential separations between DA
and UA are 170 mV using CV and 160 mV using DPV, respectively, which are large enough for the selective and simultaneous determination
of these species. In the presence of 0.5 mM AA, the DPV peak currents are linearly dependent on the concentration of UA and
DA in the range of 6–55 and 9–48 μM with correlation coefficients of 0.997 and 0.993, respectively. The detection limits (S/N = 3) for detecting UA and DA are 0.44 and 0.21 μM, respectively. The PABS–MWNT/GCE shows good reproducibility and stability
and has been used for the simultaneous determination of DA and UA in the presence of AA in samples with satisfactory results. 相似文献
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We report a sensitive and convenient voltammetric method for the direct determination of 10-hydroxycamptothecin (HCPT). At
a multi-wall carbon nanotube (MWNT)-modified electrode, HCPT yields a very sensitive and well-shaped oxidation peak, which
can be used as analytical signal for HCPT determination. Compared with the poor electrochemical signal at the unmodified GCE,
the electrochemical response of HCPT at the MWNT-modified GCE was greatly improved, as confirmed by the significant peak current
enhancement. This result indicates that the MWNT-modified GCE has great potential in the sensitive determination of HCPT.
Based on this, a very sensitive and simple electrochemical method was proposed for HCPT determination after all the experimental
parameters were optimized. The newly-proposed method possesses very low detection limit (2 × 10−9 mol L−1) and wider linear range (from 1 × 10−8 to 4 × 10−6 mol L−1). Rapid and simple sample analysis is another advantage. Finally, this method was successfully demonstrated using HCPT drugs. 相似文献
10.
采用电化学沉积法制备了纳米金修饰玻碳电极,并用循环伏安法和电化学阻抗法进行了表征,以此建立了一种直接测定鸟嘌呤的电分析方法。在磷酸盐缓冲溶液(pH 6.0)中,研究了鸟嘌呤在纳米金修饰电极上的电化学行为,实验结果表明,纳米金修饰电极可以增强鸟嘌呤在电极表面的吸附,并加快鸟嘌呤在电极表面的电子传输,使其电化学信号明显增大,检测灵敏度大大提高,该修饰电极对鸟嘌呤表现出良好的电催化性能。在优化实验条件下对鸟嘌呤进行测定,方法的线性范围为8.0×10-7~6.0×10-5mol/L,检出限为1.0×10-8mol/L,在鸟嘌呤浓度为1.0×10-5mol/L时测得RSD(n=10)为2.5%。 相似文献
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Chunya Li 《Mikrochimica acta》2007,157(1-2):21-26
Multi-wall carbon nanotubes (MWNT) were dispersed into water in the presence of dicetyl phosphate (DCP), and MWNT-DCP composite
film coated glassy carbon electrodes (GCE) were constructed. The electrochemical properties of 2-chlorophenol at a bare GCE
and MWNT-DCP modified GCE were compared. It was found that MWNT-DCP modified GCEs significantly enhance the oxidation peak
current of 2-chlorophenol and lowers its oxidation overpotential, suggesting great potential in the sensitive determination
of 2-chlorophenol. Finally, a sensitive and simple voltammetric method was developed for the determination of 2-chlorophenol.
The oxidation peak current increases linearly with the concentration in the range of 1.0 × 10−7–2.0 × 10−5 mol L−1, and the detection limit is 4.0 × 10−8 mol L−1 for 2 min accumulation. The method was successfully used to determine 2-chlorophenol in waste water samples. 相似文献
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A multi-wall carbon nanotube (MWNT) film coated glassy carbon electrode (GCE) was fabricated, and the electrochemical behavior of melatonin on the MWNT film coated GCE was investigated. The oxidation peak current of melatonin increases significantly and the oxidation peak position shifts positively at the MWNT film modified GCE compared to that at a bare GCE. This indicates that MWNTs feature highly effective catalysis to the electrochemical oxidation of melatonin. A simple and sensitive electroanalytical method was developed for the determination of melatonin. The oxidation peak current is proportional to the concentration of melatonin from 8×10–8 to 1×10–5molL–1. The detection limit is about 2×10–8molL–1 for 3min accumulation. The proposed method was demonstrated to work satisfactorily with commercial capsules. 相似文献
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Weikang Zhang Tao Liu Xiaojiang Zheng Wensheng Huang Chidan Wan 《Colloids and surfaces. B, Biointerfaces》2009,74(1):28-31
The insoluble multi-walled carbon nanotubes (MWNT) was successfully dispersed into water in the presence of hydrophobic surfactant. After that, MWNT film-coated glassy carbon electrode (GCE) was achieved via dip-coating and evaporating water. Owing to huge surface area, high sorption capacity and subtle electronic properties, MWNT film exhibits highly efficient accumulation efficiency as well as considerable surface enhancement effects to Sunset Yellow and Tartrazine. As a result, the oxidation peak currents of Sunset Yellow and Tartrazine remarkably increase at the MWNT film-modified GCE. Based on this, a novel electrochemical method was developed for the simultaneous determination of Sunset Yellow and Tartrazine. The limits of detection are 10.0 ng mL−1 (2.2 × 10−8 mol L−1) and 0.1 μg mL−1 (1.88 × 10−7 mol L−1) for Sunset Yellow and Tartrazine. Finally, the proposed method was successfully used to detect Sunset Yellow and Tartrazine in soft drinks. 相似文献
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用乙炔黑(Acetylene black,AB)和离子液体(Ionic liquid,IL)制备了乙炔黑-离子液体复合修饰玻碳电极(AB-ILs/GCE),并用电化学阻抗谱(EIS)进行了表征。采用循环伏安法(Cyclic voltammetry,CV)和计时电流法(Chronoamperometry,CA),方波伏安法(Square wave voltammetry,SWV)研究了延胡索酸泰妙菌素(TF)在此电极上电化学行为及电化学动力学性质。结果表明,TF在玻碳电极(GCE)上于0.74 V处出现一个不可逆氧化峰,与GCE相比TF在AB/GCE上的氧化峰电位基本不变,氧化峰电流增大1.8倍;而与AB/GCE相比,TF在AB-ILs/GCE上的氧化峰电位略有负移,氧化峰电流增大3倍。实验结果表明,AB-ILs/GCE对TF电化学氧化有明显的催化作用。同时考察了实验条件对TF电化学行为的影响,测定了电极反应过程动力学参数,并用本方法对TF针剂中TF含量进行了定量测定,RSD在1.1%~2.9%之间,加标回收率在98.6%~101.8%之间。据此建立了TF电化学定量测定方法。 相似文献
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Fei J Peng Y Tan H Chen X Yang J Li J 《Bioelectrochemistry (Amsterdam, Netherlands)》2007,70(2):369-374
A sensitive electrochemical method was developed for the differential pulse voltammetric determination of rhein at a glassy carbon electrode (GCE) modified with a nanoparticle composite film. In the present paper, multi-wall carbon nanotube (MWNT) was dispersed into dihexadecyl phosphate (DHP) to give a homogeneous suspension. After the solvent evaporation, a uniform film of MWNT-DHP composite film was obtained on the GCE surface. The MWNT-DHP composite film-modified GCE exhibited excellent electrocatalytic behavior toward the redox of rhein. Compared with an irreversible reduction of rhein at the bare GCE, a reversible redox behavior of rhein was observed at the MWNT-DHP composite film-modified GCE and the redox current was also enhanced greatly. Based on this, a cathodic differential pulse voltammetry (DPV) was applied for the determination of rhein. The experimental parameters, which influence the current of rhein, were optimized. Under optimal conditions, the cathodic DPV measurements were performed and a linear response of rhein was obtained in the range from 1.0 x 10(-8) to 5.0 x 10(-6) mol L(-1) and with a limit of detect (LOD) of 5.0 x 10(-9) mol L(-1). The proposed procedure was successfully applied to assay rhein in real samples with satisfactory results. 相似文献
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Chidan Wan Tao Liu Shuang Wei Shenghui Zhang 《Russian Journal of Electrochemistry》2008,44(3):327-331
In this work, a multi-wall carbon nanotube (MWNT) film-modified glassy carbon electrode (GCE) was constructed for the determination
of 8-hydroxydesoxyguanosine (8-OHdG). The electrochemical behaviors of 8-OHdG were examined using cyclic voltammetry (CV)
and linear sweep voltammetry (LSV), suggesting that MWNT film facilitates the electron transfer of 8-OHdG and then significantly
enhances the oxidation peak current of 8-OHdG. Finally, a sensitive and simple electrochemical method with a good linear relationship
in the range of 8.0 × 10−8 ∼ 5.0 × 10−6 mol 1−1, was developed for the determination of 8-OHdG. The detection limit is 9.0 × 10−9 mol 1−1 for 6-min accumulation. This newly-proposed method was successfully used to detect 8-OHdG in urine samples.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 3, pp. 351–356.
The text was submitted by the authors in English. 相似文献
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A novel room temperature ionic liquid (i.e., 1‐octyl‐3‐methylimidazolium hexafluorophosphate, OMIMPF6)‐multiwall carbon nanotube (MWNT) gel‐chitosan (Chi) composite modified glassy carbon electrode (GCE) was fabricated and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The OMIMPF6‐MWNT gel‐Chi composite showed good conductivity, stability, and extraction effect due to the synergic action of OMIMPF6, MWNT, and Chi. Furthermore, it was found that the OMIMPF6‐MWNT gel‐Chi composite had strong electrocatalytic effect on the oxidation of nitrite and at the OMIMPF6‐MWNT gel‐Chi/GCE nitrite could produce a very sensitive anodic peak. Under optimized conditions, the peak current was linear to nitrite concentration from 2.0×10?8 to 6.0×10?5 M. The detection limit was 1.0×10?8 M. The electrode also exhibited acceptable stability, repeatability and selectivity. It was used successfully for the determination of nitrite in soil, sewage and sausage samples. 相似文献
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