基于多壁碳纳米管/纳米铜复合材料的电化学传感器测定槐米中芦丁

以Nafion-多壁碳纳米管(MWNTs)薄膜修饰玻碳电极,采用恒电位法在其表面电沉积纳米Cu,研制了一种新型的芦丁电化学传感器。采用循环伏安法和电化学阻抗谱研究传感器在铁氰化钾-亚铁氰化钾体系中的电化学行为,以考察传感器的电化学性能,采用扫描电镜对传感器表面的形态进行了研究,并利用差分脉冲伏安法测定芦丁的含量。实验结果表明,该传感器对芦丁有较好的催化作用。在优化实验条件下,对芦丁检测的线性范围为1.0×10-8~1.0×10-6 mol/L,检出限为8.4×10-9 mol/L(S/N=3),回收率为98.1%~101%,该传感器制作简单,线性范围宽,灵敏度高,为槐米等样品中芦丁含量的检测提供了一种新的、行之有效的方法。     

多壁碳纳米管对质谱分析中的血清蛋白富集作用研究

通过多壁碳纳米管(MWCNTs)对临床血清蛋白提取物进行富集处理,经表面增强激光解析离子化飞行时间质谱(SELDI-TOF-MS)检测,发现MWCNTs对血清中小分子量蛋白(<20 kDa)具有很好的富集效果。同时还考察了内径、长度等参数对血清蛋白富集效果的影响。该方法可用于临床血清样本中低丰度的小分子量蛋白的检测。     

自组装纳米金的多壁碳纳米管微电极的制备及其在测定多巴胺中的应用

通过羧基化多壁碳纳米管(MWCNT′s-COOH)与巯基乙胺反应制得巯基化多壁碳纳米管(MWCNT′s-SH),将MWCNT′s-SH加入含有硼氢化钠的氯金酸溶液中,使生成的纳米金颗粒(AuNP′s)自组装到MWCNT′s-SH上,制得MWCNT′s-SH/AuNP′s粉末。将MWCNT′s-SH/AuNP′s粉末与微电极(ME)反复磨压使粉末进入ME顶端小孔内,烘干后即得MWCNT′s-SH/AuNP′s/ME。采用循环伏安法研究了多巴胺在修饰电极上的电化学行为。结果表明:多巴胺在该修饰电极上出现了一对氧化还原峰。多巴胺线性范围为5.0×10-6～6.4×10-4 mol.L-1,检出限(3S/N)为5.1×10-9 mol.L-1。修饰电极用于盐酸多巴胺注射液中多巴胺的测定,测定值与标示值相符,加标回收率在98.0%～103.0%之间。     

焙烧法纯化多壁碳纳米管

自碳纳米管[1 ] 发现以来 ,已在世界范围内掀起了碳纳米管研究和应用的热潮 .其中一些文献报道了纯化单壁碳纳米管的方法 ,如超声波助滤法 [2 ] ,酸洗法 [3,4] ,微孔膜过滤法 [5,6] ,离心法[5] ,氧化法[5,7] ;另有少量文献报道了纯化多壁碳纳米管的方法 ,如氧化法 [5,8] ,石墨插层化合物纯化法 [9] 等 .本文使用焙烧法纯化实验室自制的多壁碳纳米管 .通过 TEM、XRD和比表面积等的测定 ,考察了不同焙烧时间的纯化效果 .采用催化甲烷裂解方法 ,在 6 0 0℃反应 4h制得多壁碳纳米管 ,粗产物收率接近 2 0 % .于干燥、洁净的坩埚中 ,分别称取 6…     

多壁碳纳米管-离子液体凝胶修饰电极对放线菌素D的高灵敏检测

以多壁碳纳米管和离子液体1-正丁基-3-甲基咪唑六氟磷酸盐(BMIMPF6)为修饰剂,研制了多壁碳纳米管-离子液体凝胶修饰玻碳电极(MWNTs-BMIMPF6/GCE),并研究了放线菌素D在该电极上的电化学行为。实验结果表明,放线菌素D于-0.09 V处有一明显的氧化峰,在pH=4.8的HAc-NaAc缓冲溶液中,放线菌素D在该修饰电极上产生的氧化峰电流比在多壁碳纳米管修饰玻碳电极上显著增大。在选定实验条件下,放线菌素D的氧化峰电流与其浓度在2.0×10-8~8.0×10-7mol/L的范围内呈良好的线性关系,检出限为7.5×10-9mol/L。该方法可用于注射液中放线菌素D的测定。     

多壁碳纳米管-环氧树脂纳米复合材料的γ-射线固化行为

通过γ-射线辐射固化制备了多壁碳纳米管-环氧树脂复合材料.采用索氏提取法、傅里叶变换红外光谱(FT-IR)和差示扫描量热法(DSC)测试了多壁碳纳米管-环氧树脂复合体系的凝胶含量、转化率及热流曲线等固化动力学参数.采用扫描电子显微镜(SEM)表征了复合材料的微观组织.结果表明:通过γ-射线辐射固化的复合体系的凝胶含量随着辐射剂量、光引发剂含量的增加而增加;由于多壁碳纳米管对活性反应中心的影响,转化率随着多壁碳纳米管加入量的增加呈先下降,后增加的趋势.复合体系中多壁碳纳米管含量较高时易发生团聚,团聚会对复合体系的固化行为产生一定影响.     

接枝聚苯乙烯/多壁碳纳米管纳米复合材料制备及合成机理

通过原位悬浮聚合的方法, 以过氧化苯甲酰(BPO)做引发剂, 制备了聚苯乙烯/多壁碳纳米管(MWNT-g-PS)纳米复合材料, 复合材料在水和乙醇中均表现出良好的分散性及稳定性. 通过高倍透射电镜(HRTEM)、场发射扫描电镜(FESEM)分析, 多壁碳纳米管上包覆有1～3 nm的聚苯乙烯膜, 并分布有半径从几十纳米到几百纳米不等的聚苯乙烯微球. 通过傅立叶变换红外光谱(FTIR)、拉曼光谱(Raman spectroscopy)、X光电子能谱(XPS)和热重分析(TGA)对复合材料进行分析, 结果表明, 自由基将多壁碳纳米管表面π键打开, 形成一种新的自由基, 引发聚苯乙烯的自由基聚合, 形成了接枝聚苯乙烯/多壁碳纳米管纳米复合材料.     

基于多壁碳纳米管和纳米金修饰电极测定特殊序列DNA的电化学生物传感器的制备

基于多壁碳纳米管和纳米金复合膜修饰电极制备了特殊序列的靶DNA的电化学生物传感器.该传感器以六氨基合钌为杂交指示剂,用差示脉冲伏安法进行检测DNA杂化,其响应信号与靶DNA浓度在1.0×10<'-12>～1.0×10<'-7>mol/L范围内呈线性关系,检测限达3.5×10<'-13>mol/L.该传感器能区分单碱基错配的靶DNA.     

多壁碳纳米管互连的单壁碳纳米管晶体管的频率特性

用多壁碳纳米管(MWCNTs)作为互连线制备出了单壁碳纳米管场效应晶体管(SWCNT FETs), 对比研究了用多壁碳纳米管作为互连线和用金属作为互连线的两种情况. 结果表明, 二者的直流(DC)性能基本一致, 而用多壁碳纳米管作为互连线的交流(AC)性能略优于用金属作为互连的情况. 交流测量表明, 至少在20 MHz的频率下, 多壁碳纳米管互连的单壁碳纳米管晶体管仍有很好的响应速率, 器件能够正常工作.     

Rich-defect carbon nanotubes for highly sensitive detection of Dopamine

Dopamine (DA) plays an essential role in the central nervous, renal, hormonal and cardiovascular systems. Various modified carbon nanotubes (CNT)-based dopamine sensors have been reported, but inexpensive, highly sensitive plain CNT-based ones are seldom studied. In this work, a facile and inexpensive CNT-based DA sensor is made by rich-defect multi-walled carbon nanotubes (RD-CNT) via an ultrasound method. The defect and elemental states of the RD-CNT are systematically studied by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, X-ray powder diffraction (XRD) and X-ray-photoelectron spectroscopy (XPS). Results show that massive holes and cracks exist in RD-CNT. The level of defects increases from the additional exposed edges. The electrochemical characterizations indicate that the electrochemical sensor has the highest sensitivity of 438.4 μA/(μM ⋅ cm²) among all carbon materials-based DA sensors while well meeting the clinically required detection range and selectivity. The DA sensor was further used to detect live healthy human serum and live PC12 cells with satisfactory results, thus holding great promise for an inexpensive but sensitive DA sensor in practical applications of clinical diagnosis and biological research.     

Functionalised multi-walled carbon nanotubes-modified electrode for sensitive determination of Diuron in seawater samples

ABSTRACT

This work was focused in to develop an electroanalytical method based on a direct modification of a glassy carbon electrode (GCE) by the deposition of successive aliquots of diluted dispersions of functionalised carbon nanotubes (MWCNT-COOH) in ethanol (0.1 mg.mL^?1) aiming the determination of Diuron into seawater samples, a common antifouling substance, using differential pulse voltammetry as electroanalytical technique. The GCE/MWCNT-COOH showed a sensitivity of 2.20 μA/μmol L^?1 about 10 times higher than the unmodified counterpart (GCE) which showed a sensitivity of 0.192 μA/μmol L^?1. The limits of detection and quantificationwere 6.88 × 10^?8 and 2.29 × 10^?7 mol L^?1 for GCE/MWCNT-COOH while for GCE were 7.87 × 10^?7 and 2.62 × 10^?6 mol L^?1, respectively. The applicability was evaluated with spiked detectable amounts of Diuron into seawater samples. The recovery results were between 76% and 119%.     

Affinity-based elimination of aromatic VOCs by highly crystalline multi-walled carbon nanotubes

Carbon nanotubes (CNTs) are capable of adsorbing pollutant chemicals. Their adsorptive capacities and adsorbing mechanisms, however, are not fully understood. As-grown CNTs often contain both crystalline and amorphous carbon, and the ratio of carbon types can affect adsorption. In this study, highly crystalline multi-walled carbon nanotubes (HC-MWCNTs) were used as the adsorbent for volatile organic compounds (VOCs) in contaminated air samples. Air containing 23 added VOCs (1,1-dichloroethylene, dichloromethane, trans-1,2-dichloroethylene, cis-1,2-dichloroethylene, chloroform, 1,1,1-trichloroethane, carbon tetrachloride, 1,2-dichloroethane, benzene, trichloroethylene, 1,2-dichloropropane, bromodichloromethane, cis-1,3-dichloropropene, toluene, trans-1,3-dichloropropene, 1,1,2-trichloroethane, tetrachloroethylene, dibromochloromethane, m-xylene, p-xylene, o-xylene, bromoform, and p-dichlorobenzene) was used for model samples. Adsorptive experiments were carried out by passing the air samples through a cartridge packed with HC-MWCNTs. Initial results showing high selectivity and high affinity for adsorbing aromatic VOCs (benzene, toluene, m-xylene, p-xylene, o-xylene, and p-dichlorobenzene) have provided new insight into the adsorption mechanisms. Data suggest that the HC-MWCNTs, unlike conventional carbon materials, adsorb aromatic compounds according to Fukui's frontier theory, which is based on the interactions between the HOMO and LUMO of the aromatic VOCs and those of the HC-MWCNTs.     

Nd_2O_3/多壁碳纳米管修饰电极检测亚硝酸根

制备了纳米Nd2O3/多壁碳纳米管修饰电极并用于亚硝酸盐的检测。采用原子力显微镜、X-粉末衍射仪表征制备的纳米材料。实验表明:修饰电极对亚硝酸根的氧化具有明显地电催化作用。利用示差脉冲伏安法测定亚硝酸盐,其氧化峰电流和其浓度在20μmol·L-1-20 mmol·L-1范围内呈现良好的线性关系,检测线为0.83μmol·L-1(S/N=3)。更重要的是,实验结果表明:与Nd2O3修饰电极相比,多壁碳纳米管能显著地提高电极的稳定性。此外,修饰电极具有良好的选择性,能用于样品的检测,结果令人满意。     

Amine-functionalized low-cost industrial grade multi-walled carbon nanotubes for the capture of carbon dioxide

Industrial grade multi-walled carbon nanotubes (IG-MWCNTs) are a low-cost substitute for commercially purified multi-walled carbon nanotubes (P-MWCNTs). In this work, IG-MWCNTs were functionalized with tetraethylenepentamine (TEPA) for CO₂ capture. The TEPA impregnated IG-MWCNTs were characterized with various experimental methods including N₂ adsorption/desorption isotherms, elemental analysis, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. Both the adsorption isotherms of IG-MWCNTs-n and the isosteric heats of different adsorption capacities were obtained from experiments. TEPA impregnated IG-MWCNTs were also shown to have high CO₂ adsorption capacity comparable to that of TEPA impregnated P-MWCNTs. The adsorption capacity of IG-MWCNTs based adsorbents was in the range of 2.145 to 3.088 mmol/g, depending on adsorption temperatures. Having the advantages of low-cost and high adsorption capacity, TEPA impregnated IG-MWCNTs seem to be a promising adsorbent for CO₂ capture from flue gas.     

Determination of trace thiocyanate with nano-silver coated multi-walled carbon nanotubes modified glassy carbon electrode

Novel nano-silver coated multi-walled carbon nanotube composites were prepared and used to fabricate a modified electrode. The application of the nano-silver coated multi-walled carbon nanotube composites modified electrode for determination of trace thiocyanate is demonstrated for the first time. The influence of substrate, pH and interference of coexisting substances was investigated for response properties of the electrode. There was a linear relationship at the range 2.5 × 10⁻⁹ to 5 × 10⁻⁸ mol L⁻¹ and 5 × 10⁻⁸ to 1 × 10⁻⁶ mol L⁻¹ of thiocyanate with the decrement of anodic DPV peak currents. The limit of detection was 1 × 10⁻⁹ mol L⁻¹(S/N = 3). The constructed electrode showed excellent reproducibility and stability. Actual urine and saliva samples of smoker and non-smoker were analyzed and satisfactory results were obtained. This method provides a new way to construct any electrode for biological and environmental analysis.     

DNA在纳米碳管上的检测及甘草素-Cu(II)对DNA的损伤研究

本文用恒电位溶出法测定了单链、双链DNA在纳米碳管上的电化学行为,详细讨论了各种因素的影响,并研究了甘草素在铜离子的存在下对DNA的损伤作用,发现在0.84 V左右出现一个新峰,1.06 V的峰升高。同时用压电石英阻抗技术实时监测了这个损伤过程,进行进一步地佐证,频率的变化是损伤过程中的DNA降解导致的溶液粘密度变化所产生的。     

Ionic liquids coated multi-walled carbon nanotubes as a novel pseudostationary phase in electrokinetic chromatography

A new CE system using ionic liquids coated multi-walled carbon nanotubes (ILs-MWNTs) as pseudostationary phase was developed for the simultaneous determination of four flavonoids, four phenolic acids and two saponins. Several parameters affecting the separation were studied, including the choice of ILs, ILs-MWNTs concentration, the respective use of ILs and MWNTs, buffer pH, SDS concentration and borate content. Results revealed that the addition of ILs-MWNTs in running electrolytes enhanced the separation of target compounds compared to conventional micelle because the surface of carbon nanotubes interacted favorably with the analytes. Under the optimum conditions, a baseline separation was achieved for these analytes within 11 min in a 41.5 cm of effective length fused-silica capillary. At a voltage of 28.0 kV, the separation was carried out in a 10mM borate buffer (pH 9.0) containing 100mM SDS, 6% propanol and 4 μg mL(-1) ILs-MWNTs. All calibration curves showed good linearity (r(2)>0.9990) within the test ranges. The intra- and inter-day precisions as determined from standard solutions were below 3.30% and 6.23%, respectively. The recoveries for ten compounds were found to range from 85.5 to 101.8%. The method was successfully applied for the determination of three types of compounds in Qishenyiqi dropping pills. Our experimental results indicated that the proposed method offered new opportunities for the analysis of complex samples.     

Covalent immobilization of tyrosinase on magnetic multi-walled carbon nanotubes for inhibitor screening

The inhibition of tyrosinase is considered to be a common therapeutic strategy for some hyperpigmentation disorders. Screening of tyrosinase inhibitors is of great significance to the treatment of pigmentation diseases. In this study, tyrosinase was covalently immobilized on magnetic multi-walled carbon nanotubes for the first time, and the immobilized tyrosinase was applied for ligand fishing of tyrosinase inhibitors from complex medicinal plants. The immobilized tyrosinase was characterized by transmission electron microscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, vibrating sample magnetometry, and thermo-gravimetric analyzer, which indicated that tyrosinase was immobilized onto magnetic multi-walled carbon nanotubes. The immobilized tyrosinase showed better thermal stability and reusability than the free one. The ligand was fished out from Radix Paeoniae Alba and identified as 1,2,3,4,6-pentagalloylglucose by ultra-performance liquid chromatography-quadrupole time-of-flight high-resolution mass spectrometry. 1,2,3,4,6-pentagalloylglucose was found to be a tyrosinase inhibitor with similar half maximal inhibitory concentration values of 57.13 ± 0.91 μM compared to kojic acid (41.96 ± 0.78 μM). This work not only established a new method for screening tyrosinase inhibitors but also holds considerable potential for exploring the new medicinal value of medicinal plants.     

Oxalic acid removal from wastewater using multi-walled carbon nanotubes: Kinetic and equilibrium analysis

Oxalic acid adsorption from aqueous solution is studied in this work. Multi-walled carbon nanotubes (MWCNT) were used as an adsorbent. The investigated adsorption variables are equilibrium time, initial acid concentration, and temperature. The experimental results were presented using equilibrium isotherm and kinetic models. The used equilibrium models are Langmuir, Freundlich, and Temkin adsorption isotherms. And the kinetic models are Elovich, Lagergren pseudo-first-order and pseudo-second-order kinetic models. The thermodynamics studies were carried out at three different temperatures: 278, 298, and 318 K. Langmuir isotherm was the best fitted equilibrium model for the experimental data. The all applied kinetic models fitted the data suitably.