Electrochemical Determination of 4-Nitrophenol Using a Single-Wall Carbon Nanotube Film-Coated Glassy Carbon Electrode

A single-wall carbon nanotubes (SWNT) film coated glassy carbon electrode (GCE) was fabricated for the direct determination of 4-nitrophenol (4-NP). The electrochemical behaviors of 4-NP at the SWNT-film coated GCE were examined. In 0.1M phosphate buffer with a pH of 5.0, 4-NP yields a very sensitive and well-defined reduction peak at the SWNT-modified GCE. It is found that the SWNT film exhibits obvious electrocatalytic activity towards the reduction of 4-NP since it not only increases the reduction peak current but also lowers the reduction overpotential. Based on this, an electrochemical method was proposed for the direct determination of 4-NP. The reduction peak current varies linearly with the concentration of 4-NP ranging from 1×10^–8 to 5×10^–6M, and the detection limit is 2.5×10^–9M after 3min of open-circuit accumulation. The relative standard deviation at 2×10^–7M 4-NP was about 6% (n=10), suggesting excellent reproducibility. This new method was successfully employed to determine 4-NP in several lake water samples.     

多壁碳纳米管修饰玻碳电极测定多巴酚丁胺的研究

研究了多巴酚丁胺在多壁碳纳米管修饰电极上的电化学行为,建立了一种直接测定多巴酚丁胺的电化学方法。在0.3mol·L-1H2SO4底液中,氧化峰电位为0.57V(vs.Ag/AgCl),峰电流与多巴酚丁胺的浓度在5.0×10-8～1.0×10-5mol·L-1范围内呈良好的线性关系。该法的检出限为3.0×10-8mol·L-1。平均回收率为99.15%。1.0×10-5mol·L-1多巴酚丁胺平行测定8次的标准偏差为4.8%。用拟定的方法测定了多巴酚丁胺注射液中多巴酚丁胺的含量,结果满意。     

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.     

多壁碳纳米管化学修饰电极测定替硝唑的研究

替硝唑(Tinidazole,TNZ)是继甲硝唑后新一代的抗厌氧菌和抗滴虫的国家级二类新药,可广泛应用于临床各种厌氧菌感染。其测定方法有紫外分光光度法、高效液相色谱法、光度法及电化学方法等。但用碳纳米管修饰电极测定TNZ还未见报道。     

Untersuchung Der Kcmplexbildung Von Thallium(III) Mit 1-Phenyl-3-Methyl-4-Benzoylpyrazolon-5

Abstract

A study has been made of the method used for extracting the complex formed between thallium(III) and PhMBP. It has been demonstrated that thallium(III) can be readily extracted as a complex with PhMBP by organic solvents at low pH. The extraction of thallium(III) has been studied as a function of pH, concentration of reagent, nature of solvent, duration of contact of the phases and concentration of thallium(III). It has been established that thallium(III) forms a complex with PhMBP of the type MA_n, where n=3. The stability constants and distribution constant of the neutral complex has been calculated by the method of Leden-Rydberg.     

Nafion修饰玻碳电极吸附伏安法直接测定邻氨基苯酚

在 p H=2 .0的 0 .1 mol/ L H3 PO4 缓冲溶液中 ,开路搅拌富集 2 min后 ,从 0 .0 0～ +1 .0 0 V阳极扫描 ,OAP在 Nafion修饰玻碳电极上出现一灵敏的氧化峰 ,峰电位位于 0 .44 V。该峰电流与 OAP在 1× 1 0 - 7～ 2 .5× 1 0 - 5mol/ L的浓度范围内有良好的线性关系 ,检出限为 1× 1 0 - 8mol/ L。对支持电解质的种类及 p H值、Nafion的用量、富集电位及时间、以及扫描速度等进行了优化 ,提出了一种直接测定邻氨基苯酚的电化学方法。将此方法用于水样中邻氨基苯酚的测定 ,取得了满意的结果     

CdS修饰玻碳电极电化学发光法检测三聚氰胺

本文将CdS纳米棒修饰到玻碳电极上制作了CdS修饰玻碳电极(CdS/GCE)并研究了其在K2S2O8溶液中的电化学发光(ECL)性能.基于三聚氰胺能淬灭CdSK2s2O8电化学发光的性质建立了一种检测三聚氰胺的方法.在最优条件下,体系的ECL强度与三聚氰胺浓度在1.0×10-9～1.0×10-7 mol/L范围内与EC...     

用多壁碳纳米管修饰玻碳电极为工作电极循环伏安法测定辛硫磷

将多壁碳纳米管(MWCNT′s)置于硝酸-硫酸(1+1)溶液中回流6 h使之净化及功能化。取MWCNT′s 5 mg置于超纯水10 mL中经超声振荡20 min制得其悬浮液,取悬浮液10μL滴加在玻碳电极(GCE)表面,经自然干燥后即得用MWCNT′s修饰的玻碳电极(MWCNT′s/GCE)。基于此修饰电极对辛硫磷的催化还原反应,提出了蔬菜中辛硫磷的循环伏安测定法,在pH 4的乙酸盐支持电解质溶液中,在电位0.78 V(对SCE)处可见明显的还原峰,且其峰电流值与辛硫磷浓度在5.0×10-8~1.0×10-6mol.L-1之间呈线性关系。应用此法分析了两件蔬菜样品,并以此试样为基体加入标准溶液对方法进行回收及精密度试验,测得其回收率的平均值和相对标准偏差(n=5)分别依次为100.3%,96.5%及3.7%,3.2%。     

多壁碳纳米管-Nafion复合膜修饰玻碳电极测定硝苯地平的研究

研制了以Nafion分散羧基化多壁碳纳米管的化学修饰电极(Nafion-MWCNTs/GC),研究了硝苯地平(NIF)在修饰电极上的电化学行为和测定方法。实验结果表明,在0.1mol/LNH3-NH4Cl(pH9.6)溶液中,Nafion-MWCNTs/GC,对NIF具有明显的催化和增敏作用,还原峰电位由-0.85V(裸电极)正移到-0.75V(vs.AgCl/Ag)(修饰电极),灵敏度增加约7倍。对各种实验条件进行了优化。定量测定的线性范围为2.5×10-7~4.5×10-5mol/L,r为0.9974;检出限为8.0×10-8mol/L。探讨了NIF在Nafion-MWCNTs/GC上的电极过程和反应机理,测得在本体系中参与反应的质子数和电子转移数均为4,电子转移系数α为0.41。对NIF药片进行了测定,回收率为94.5%~101.0%。     

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.     

Electrolysis of Nitric Acid by Using a Glassy Carbon Fiber Column Electrode System

The electrochemical redox behavior of nitric acid was studied using a glassy carbon fiber column electrode system, and its reaction mechanism was suggested and confirmed in several ways. Electrochemical reactions in less than 2.0M nitric acid was not observed. However, in more than 2.0M nitric acid, the reduction of nitric acid to nitrous acid occurred and the reduction rate was slow so that the nitric acid solution had to be in contact with an electrode for a period of time long enough for an apparent reduction current of nitric acid to nitrous acid to be observed. The nitrous acid generated in more than 2.0M nitric acid was rapidly and easily reduced to nitric oxide by an autocatalytic reaction. Sulfamic acid was confirmed to be effective to destroy the nitrous acid. At least 0.05M sulfamic acid was necessary to scavenge the nitrous acid generated in 3.5M nitric acid.     

碳纳米管化学修饰电极测定土壤沉积物中的铜

本文研究了在碳纳米管(CNT)修饰的玻碳电极上,用微分脉冲溶出伏安法(DPSV)对土壤沉积物中铜的测定方法,在1.0mol/L的HCl介质中,于-0.6V电位处富集240s,静置10s,在阳极扫描过程中,被富集于修饰电极表面的铜在约-0.25V电位处出现特定的溶出峰,据此实现铜离子的测定。该方法的线性范围为8.0×10-7～1.2×10-5mol/L,检出限为2.0×10-7mol/L,结果令人满意     

Synthesis,Structure and Photochromic Properties of 1-Phenyl-3-Methyl-4-(4-Bromobenzal)-Pyrazolone-5 Thiosemicarbazone

A new organic photochromic compound containing pyrazolone-ring, 1-phenyl-3-methyl-4-(4-bromobenzal)-pyrazolone-5 thiosemicarbazone (PM4BrBP-TSC), was synthesized and characterized by elemental analyses and single crystal X-ray diffraction. The X-ray determination indicated that PM4BrBP-TSC is of orthorhombic system, space group Pbca with cell dimensions of a = 12.184(2) Å, b = 18.121(3) Å, c = 18.554(4) Å, V = 4096.4(12) ų, Z = 8 and R = 0.0387. The photochromic properties and photocolored kinetics of PM4BrBP-TSC were studied by Time-dependent UV-Vis reflectance spectra and fluorescence spectra under 365 nm light irradiation. The crystal structure analysis showed that the photochromic properties were related to the photoisomerization from enol tautomer to keto one.     

Simultaneous Determination of Fat-Soluble Vitamins by Using Modified Glassy Carbon Electrode

Russian Journal of Electrochemistry - This study demonstrates the development of an electrochemical sensor based on β-cyclodextrin/multi-wall carbon nanotubes modified glassy carbon electrode...     

硫桥杯[4]芳烃衍生物膜修饰玻碳电极差分脉冲溶出伏安法测定铅

将硫桥杯[4]芳烃衍生物25,27-二(2-噻二唑基硫代乙氧基)-26,28-二甲氧基-5,11,17,23-四叔丁基硫桥杯[4]芳烃(TTCA)溶于二氯甲烷中,滴涂在玻碳电极表面,制得硫桥杯[4]芳烃修饰的玻碳电极。循环伏安当研究结果表明:将此修饰电极浸泡在1.0×10-6mol.L-1铅(Ⅱ)溶液中一段时间后转移至0.1 mol.L-1硝酸溶液中,以扫速100 mV.s-1在电位-0.8~-0.2 V范围内扫描所得的CV图上出现一对氧化还原峰。当此修饰电极在上述浓度的铅(Ⅱ)溶液中于-1.1 V富集300 s后用差分脉冲溶出伏安法检测时,铅(Ⅱ)在-0.516 V处出现一良好的氧化峰。铅(Ⅱ)浓度在2.0×10-7~2.0×10-5mol.L-1范围内与峰电流呈线性关系。其检出限(3S/N)为8.0×10-9mol.L-1。此法应用于水样中痕量铅的测定,测得回收率在95.0%~104.0%之间。     

Clay Catalysis: Dry Condensation of 3-Methyl-1- Phenyl-5-Pyrazolone with Aldehydes Under Microwave Irradiation

3-Methyl-1-phenyl -5-pyrazolone (1) and arylcarboxyaldehydes (2) were condensated to 1-phenyl-3-methyl-4-(arylmethylene)-5-pyrazolone (3) in presence of acidic clay KSF without solvent under microwave irradiation.     

Determination of Rutin by a Graphene-Modified Glassy Carbon Electrode

A reduced graphene oxide-modified glassy carbon electrode for sensitive detection of rutin is reported. The modified electrode was obtained by one-step electrochemical reduction of graphene oxide on the bare glassy carbon electrode. In the presence of graphene, an enhanced electrochemical response for rutin appeared with a pair of well-defined anodic and cathodic peaks in pH 3.0 phosphate buffer. Under the optimized conditions, the anodic peak currents exhibited a linear relationship with rutin concentration from 0.1 to 2.0 µM with a detection limit of 23.2 nM. The modified electrode was employed to the analysis of tablets (with satisfactory recovery of 19.96 mg/per tablet) and Flos Sophorae. The graphene-modified electrode exhibited high sensitivity, good stability, and selectivity for the determination of rutin.     

双嘧达莫在玻碳电极上的阳极伏安法研究

用直流伏安法(DCV),微分脉冲伏安法(DPV)和循环伏安法(CV)在玻碳电极(GCE)上研究了双嘧达莫(DPM)在不同介质中的阳极伏安行为,发现在0.01mol/LCHl溶液中于0.62V(vs.Ag/AgCl)右左生产一个阳极氧化峰,其峰高与浓度的线性方程分别为r=0.0004 0.17C(0.05~1.0mg/L)和y=0.052 0.22C(0.5~10mg/L). 在此体中大多数金属离子和20多种有机生代物质不干扰测定,采用该方法可不经分离,直接测定药物制剂和尿样吕DPM的含量,同时对DPM的电极反反应机理进行了探讨.     

石墨烯/L-胱氨酸复合膜修饰玻碳电极测定盐酸异丙肾上腺素的研究

研制了石墨烯与L-胱氨酸复合膜化学修饰电极(GR-L-CysS/GCE),并研究了盐酸异丙肾上腺素在修饰电极上的电化学行为和测定方法.结果表明,在0.2 mol/L Na2HPO4-柠檬酸(pH 7.4)溶液中,GR-L-CysS/GCE对盐酸异丙肾上腺素的电化学氧化具有明显的催化增敏作用,氧化峰电流相对于在裸玻碳电极上增加了13倍.在优化实验条件下,定量测定的线性范围为4.0×10-6～1.6×10-4 mol/L,r为0.9977,方法检出限(S/N=3)为8.4×10-7 mol/L.探讨了盐酸异丙肾上腺素在GR-L-CysS/GCE上的电催化过程和反应机理,测得在本体系中参与反应的电子转移数和质子数均为1,电子转移系数为0.4635.对样品进行测定及加标回收实验,回收率在94.9％～102.9％之间.     

Sandwich Immunoassay for Hepatitis C Virus Non-Structural 5A Protein Using a Glassy Carbon Electrode Modified with an Au-MoO3/Chitosan Nanocomposite

A novel electrochemical immunosensor was prepared for the detection of the hepatitis C virus non-structural 5A protein. A glassy carbon electrode was modified with an Au-MoO₃/Chitosan nanocomposite that warranted good conductivity and biocompatibility. Mesoporous silica with a large specific surface served as a nanocarrier for horseradish peroxidase and the polyclonal antibody as the reporter probe. The immunosensor was characterized by scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Following the sandwich-type immunoreaction, horseradish peroxidase was efficiently captured on the surface of the electrode to catalyze the decomposition of hydrogen peroxide. The analytical signal was obtained as an amperometric i-t curve (chronoamperometry). The assay reported here had a wide detection range (1 ng mL^?1 ?50 µg mL^?1) and detection limit as low as 1 ng mL^?1 of hepatitis C virus non-structural 5A protein. The electrochemical biosensor experiments showed excellent reproducibility, high selectivity, and outstanding stability for the determination of hepatitis C virus non-structural 5A protein, and it was successfully applied to the detection of the analyte in real serum samples.