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1.
A new voltammetric sensor, Langmuir–Blodgett (LB) film of a p‐tert‐butylcalix[4]arene derivative modified glassy carbon electrode, was designed and successfully used in simultaneous determination of Tl+ and Pb2+ by square‐wave anodic stripping voltammetry. Under the optimum experimental conditions, this newly developed sensor reveal good linear response for Tl+ and Pb2+ in the concentration range of 3×10?8–4×10?6 mol L?1 and 2×10?7–2×10?5 mol L?1 respectively. The detect limits are 2×10?8 mol L?1 for Tl+ and 8×10?8 mol L?1 for Pb2+. Using proposed method, Tl+ and Pb2+ in environment samples were determined with satisfactory results. 相似文献
2.
A new type of voltammetric sensor, Langmuir‐Blodgett (LB) film of 5,11,17,23‐tetra‐tert‐butyl‐25,27‐di(3‐thiadiazole‐propanoxy)‐26,28‐dihydroxycalix[4]arene modified glassy carbon electrode (LBTZCA–GCE), was prepared. The electrochemical properties of LBTZCA–GCE were researched in detail and its recognizing mechanism for silver ion in aqueous solution was discussed. Using this voltammetric sensor, a new stripping voltammetric method for determining of Ag+ was erected with good sensitivity, selectivity, reproducibility and recovery. The detection limit was 8×10?9 M at accumulation time of 180 s. By this method, real samples (lake water, tap water and synthesis sample) were analyzed and the results obtained were well satisfactory. 相似文献
3.
The electrochemical behavior of 5,11,17,23‐Tetrakis‐dimethylaminomethylcalix[4]arene (DCA) has been investigated by cyclic voltammetry (CV). The results show that there is an irreversible electrochemical oxidative wave with peak potential of 1.35 V in chloroform at a glassy carbon electrode. The kinetic parameters of the andic wave, such as α, n and ks, were discussed. In addition, a new pair of quasi‐reversible redox peaks with peak potentials of 0.72 V and 0.94 V was found. It can result in DCA electrodeposition at the electrode surface. This film modified electrode was characterized by CV and electrochemical impedance spectroscopy (EIS). Moreover, the possible mechanism of electrodeposition was also discussed 相似文献
4.
Wenfang Deng Yueming Tan Zhengfa Fang Qingji Xie Yunyong Li Xiaoling Liang Shouzhuo Yao 《Electroanalysis》2009,21(22):2477-2485
A 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate) diammonium salt (ABTS)‐multiwalled carbon nanotubes (MWCNTs) nanocomposite/Bi film modified glassy carbon (GC) electrode was constructed for the differential pulse stripping voltammetric determination of trace Pb2+ and Cd2+. This electrode was more sensitive than ABTS‐free Bi/GC and Bi/MWCNTs/GC electrodes. Linear responses were obtained in the range from 0.5 to 35 μg L?1 for Cd2+ and 0.2 to 50 μg L?1 Pb(II), with detection limits of 0.2 μg L?1 for Cd2+ and 0.1 μg L?1 for Pb2+, respectively. This sensor was applied to the simultaneous detection of Cd2+ and Pb2+ in water samples with satisfactory recovery. 相似文献
5.
A glassy carbon electrode coated the film of 4‐tert‐butyl‐1‐(ethoxycarbonylmethoxy)thiacalix[4]arene is designed for the determination of trace amounts of Hg2+. Compared with bare glassy carbon electrode, the modified electrode can improve the measuring sensitivity of Hg2+. Under the optimum experimental condition, the modified electrode in 0.1 mol L?1 H2SO4 + 0.01 mol L?1 KCl solution shows a linear voltammetric response in the range of 8.0 × 10?9 ~ 3.0 × 10?6 mol L?1 with detection limit 5.0 × 10?9 mol L?1 for Hg2+. The high sensitivity, selectivity, and stability of modified electrode also prove its practical application for a simple, rapid and economical determination of Hg2+ in water samples. 相似文献
6.
A Simple and Highly Sensitive Electrochemically Reduced p‐Nitrobenzoic Acid Film Modified Sensor for Determination of Mercury
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Herein, a simple electrochemical sensor was fabricated for sensing Hg2+ ions by using electrochemically reduced p‐nitrobenzoic acid molecules modified (ERpNBA) glassy carbon electrode (GCE). The modified electrode was applied for the determination of Hg2+ ions by using differential pulse anodic stripping voltammetry (DPASV). Experimental parameters such as concentration of p‐nitrobenzoic acid used for electrode modification, pH, accumulation time and deposition potential used for the determination of Hg2+ ions were optimized. The strong interaction between the Hg2+ ions and the lone pair of electrons on the nitrogen atoms of ERpNBA molecules leads to highly selective adsorption of Hg2+ ions on the modified electrode. Under the optimum experimental conditions, the sensor showed higher sensitivity and very low detection limit for Hg2+ ions than other metal ions such as Cd2+, Pb2+ and Zn2+ ions. The LOD for Hg2+ ions was 240 pM which is below the guideline value given by the World Health Organization and the earlier reports. 相似文献
7.
The competitive removal of Pb2+, Cu2+, and Cd2+ ions from aqueous solutions by the copolymer of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS) and itaconic acid (IA), P(AMPS‐co‐IA), was investigated. Homopolymer of AMPS (PAMPS) was also used to remove these ions from their aqueous solution. In the preparation of AMPS–IA copolymer, the molar percentages of AMPS and IA were 80 and 20, respectively. In order to observe the changes in the structures of polymers due to metal adsorption, FTIR spectra by attenuated total reflectancetechnique and scanning electron microscopy (SEM) pictures of the polymers were taken both before and after adsorption experiments. Total metal ion removal capacities of PAMPS and P(AMPS‐co‐IA) were 1.685 and 1.722 mmol Me2+/gpolymer, respectively. Experimental data were evaluated to determine the kinetic characteristics of the adsorption process. Competitive adsorption of Pb2+, Cu2+, and Cd2+ ions onto both PAMPS and P(AMPS‐co‐IA) was found to fit pseudo‐second‐order type kinetics. In addition, the removal orders in the competitive adsorption of these metal ions onto PAMPS and P(AMPS‐co‐IA) were found to be Cd2+ > Pb2+ > Cu2+ and Pb2+ > Cd2+ > Cu2+, respectively. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
8.
Prussian blue nanoparticles (PBNPs) were prepared by a self‐assembly process on a glassy carbon electrode (GCE) modified with poly(o‐phenylenediamine) (PoPD) film. The stepwise fabrication process of PBNP‐modified PoPD/GCE was characterized using scanning electron microscopy and electrochemical impedance spectroscopy. The prepared PBNPs showed an average size of 70 nm and a homogeneous distribution on the surface of the modified electrode. The PBNPs/PoPD/GCE showed electrocatalytic activity towards the oxidation of pyridoxine (PN) and was used as an amperometric sensor. The modified electrode exhibited a linear response for PN oxidation over the concentration range 3–38.5 μM with a detection limit of ca 6.10 × 10?7 M (S/N = 3) and sensitivity of 2.79936 × 103 mA M?1 cm?2 using an amperometric method. The mechanism and kinetics of the catalytic oxidation reaction of PN were investigated using cyclic voltammetry and chronoamperometry. The values of α, kcat and D were estimated as 0.36, 1.089 × 102 M?1 s?1 and 8.9 × 10?5 cm2 s?1, respectively. This sensor also exhibited good anti‐interference and selectivity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
9.
A robust and effective composite film combined the benefits of Nafion, room temperature ionic liquid (RTIL) and multi‐wall carbon nanotubes (MWNTs) was prepared. Hemoglobin (Hb) was successfully immobilized on glassy carbon electrode surface by entrapping in the composite film. Direct electrochemistry and electrocatalysis of immobilized Hb were investigated in detail. A pair of well‐defined and quasi‐reversible redox peaks of Hb was obtained in 0.10 mol·L?1 pH 7.0 phosphate buffer solution (PBS), indicating that the Nafion‐RTIL‐MWNTs film showed an obvious promotion for the direct electron transfer between Hb and the underlying electrode. The immobilized Hb exhibited an excellent electrocatalytic activity towards the reduction of H2O2. The catalysis current was linear to H2O2 concentration in the range of 2.0×10?6 to 2.5×10?4 mol·L?1, with a detection limit of 8.0×10?7 mol·L?1 (S/N=3). The apparent Michaelis‐Menten constant (Kmapp) was calculated to be 0.34 mmol·L?1. Moreover, the modified electrode displayed a good stability and reproducibility. Based on the composite film, a third‐generation reagentless biosensor could be constructed for the determination of H2O2. 相似文献
10.
Ordered Mesoporous Carbon and Thiolated Polyaniline Modified Electrode for Simultaneous Determination of Cadmium(II) and Lead(II) by Anodic Stripping Voltammetry
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Lin Tang Jun Chen Guangming Zeng Yuan Zhu Yi Zhang Yaoyu Zhou Xia Xie Guide Yang Sheng Zhang 《Electroanalysis》2014,26(10):2283-2291
The fabrication and evaluation of a glassy carbon electrode (GCE) modified with ordered mesoporous carbon (OMC), 2‐mercaptoethanesulfonate (MES)‐tethered polyaniline (PANI) and bismuth for simultaneous determination of trace Cd2+ and Pb2+ by differential pulse anodic stripping voltammetry (DPASV) are presented here. The morphology and electrochemical properties of the fabricated electrode were respectively characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Experimental parameters such as PANI disposition, preconcentration potential, preconcentration time and bismuth concentration were optimized. Under optimum conditions, the fabricated electrode exhibited linear calibration curves ranged from 1 to 120 nM for Cd2+ and Pb2+. The limits of detection (LOD) were 0.26 nM for Cd2+ and 0.16 nM for Pb2+ (S/N=3), respectively. Additionally, repeatability, reproducibility, interference and application were also investigated, and the proposed electrode exhibited excellent performance. The proposed method could be extended for the development of other new sensors for heavy metal determination. 相似文献
11.
This article reports the fabrication of Acid Violet 34 (AV34)/nickel hydroxide nanosheets ultrathin film on the glassy carbon electrode (GCE) via the electrostatic layer‐by‐layer (LBL) technique, and its electrocatalytic oxidation for glucose was demonstrated. UV‐vis absorption and electrochemical impedance spectra indicate the uniform deposition of the LBL film, with a continuous and smooth film surface observed by SEM and AFM. The electrochemical performance of the ultrathin film was studied by cyclic voltammetry and chronoamperometry. The (AV34/Ni(OH)2)5 ultrathin film modified electrode displays a fast direct electron transfer attributed to the Ni2+/Ni3+ redox couple as well as remarkable electrocatalytic activity towards the oxidation of glucose. The linear response was obtained in the range 0.5–13.5 mM (R=0.9994) with a low detection limit (14 µM), high sensitivity (25.9 µA mM?1 cm?2), rapid response (less than 1 s) and excellent anti‐interference properties to the species including ascorbic acid (AA), uric acid (UA), acetamidophenol (AP) and structurally related sugars. Therefore, the AV34/Ni(OH)2 ultrathin film can be potentially used as a feasible electrochemical sensor for the determination of glucose. 相似文献
12.
胆红素LB膜的电化学行为研究 总被引:1,自引:0,他引:1
胆红素(BR)是存在于动物体内的一种重要生物物质,也是人和绝大多数哺乳动物体内血红蛋白等含铁卟啉化合物分解代谢的产物和代谢中间体。它是一种内源性抗氧化剂,对肝细胞的再生具有积极的作用,BR常以线状四吡咯或类卟啉结构的形式存在。胆红素及其金属配合物在水溶液犤1~6犦与有机介质(如DMF和DMSO)犤7~9犦中的电化学行为,文献上已有较多报道。前文犤10~12犦我们报道了胆红素可在不同亚相(酸性、中性及部分金属离子)表面形成Langmuir-Blodgett(LB膜);在有磷脂存在时,其成膜性能更佳犤13犦。由于LB膜同生… 相似文献
13.
In this work, a new route to reduce the toxicity of the mercury electrode was presented. Nafion was used as soft template to generate nanosized Ag‐Hg amalgams on the surface of a glassy carbon electrode other than the traditional preparation of solid amalgam electrodes. As less mercury was used and it was immobilized by Ag and Nafion film, the toxicity of mercury was reduced. Scanning electron microscope (SEM) showed that the size of the formed nano Ag‐Hg amalgams was about 50 nm. Finally, the prepared electrode was used to the determination of heavy metals. Good reproducibility, linearity and sensitivity were obtained when it was utilized for the determination of Cd2+, Pb2+ and Cu2+ in deionized water and in tap water (without any further treatment). 相似文献
14.
Afzal Shah Victor C. Diculescu Niaz Muhammad Rumana Qureshi Saqib Ali Ana Maria Oliveira‐Brett 《Electroanalysis》2010,22(1):121-127
The electrochemical behavior of Na‐salt of 2‐methyl‐3‐(4‐nitrophenyl)acrylate (NPA) and its reduction product was studied by cyclic (CV), differential pulse(DPV) and square wave voltammetry (SWV) using a glassy carbon electrode (GCE). The results revealed that NPA is irreversibly reduced leading to the formation of a reduction product (PNPA). For pH<9.0 the peak potential was linearly dependent on pH. For pH>9.0 the peak potential was pH‐independent and the value of pKb≈9.0 was determined. The adsorbed PNPA exhibited reversible redox reaction. The reduction of PNPA was pH dependent. To ensure that the electrochemical behavior of NPA is due to the reducible moiety, NO2, closely related compounds to NPA were also studied, and a redox mechanism was proposed for NPA. 相似文献
15.
One Step Fabrication of Au Nanoparticles‐Ni‐Al Layered Double Hydroxide Composite Film for the Determination of L‐Cysteine
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This paper reports the fabrication of Au nanoparticles (Au NPs)‐Ni‐Al layerd double hydroxide (LDH) composite film by one step electrochemical deposition on the surface of a glass carbon electrode from the mixture solution containing HAuCl4 and nitrate salts of Ni2+ and Al3+. Improved conductivity was obtained by Au NPs codeposited on LDH film. The synergic effect of LDHs and Au NPs dramatically improves the performance of L ‐cysteine electro‐oxidation, displaying low oxidation peak potential (0.16 V) and high current response. Thus the electrode was used to sense L ‐cysteine, showing good sensitivity and selectivity. 相似文献
16.
A highly sensitive electrochemical biosensor for the detection of trace amounts of 8‐azaguanine has been designed. Double stranded (ds)DNA molecules are immobilized onto a glassy carbon electrode surface with Langmuir–Blodgett technique. The adsorptive voltammetric behaviors of 8‐azaguanine at DNA‐modified electrode were explored by means of cyclic voltammetry and square wave voltammetry. Compared with bare glassy carbon electrode (GCE), the Langmuir–Blodgett film modified electrode can greatly improve the measuring sensitivity of 8‐azaguanine. Under the optimum experimental conditions, the Langmuir–Blodgett film modified electrode in pH 3.0 Britton–Robinson buffer solutions shows a linear voltammetric response in the range of 5.0×10?8 to 1.0×10?5 mol L?1 with detection limit 9.0×10?9 mol L?1. The method proposed was applied successfully for the determination of 8‐azaguanine in diluted human urine with wonderful satisfactory. 相似文献
17.
《Electroanalysis》2017,29(8):1903-1910
This paper describes the electrochemical behaviors of Cd2+ and Pb2+ on the proposed mesoporous carbon microspheres/mefenamic acid/nafion modified glassy carbon electrode (MC/MA/Nafion/GC) studied by square wave anodic stripping voltammetry (SWASV). The prepared material is characterized by XRD, SEM, FTIR, RAMAN and BET analysis. Experimental parameters, such as the deposition potential and time, the pH value of buffer solution were optimized. Under the optimized conditions, the electrode responded linearly to Cd2+ and Pb2+ in the concentration range from 50 to 300 nM, and the detection limits were 24.2 and 11.26 nM respectively. The sensitivity determined was 0.0623 μA/nM (Cd2+) and 0.192 μA/nM (Pb2+). Multiple metal ion detection with clear demarcation of peaks was produced by the electrode. Moreover, the modified electrode has possessed good selectivity and reproducibility of Cd2+ and Pb2+ detection. We also investigated the interference of various anions and surfactants for the detection of Cd2+ and Pb2+ ions. Finally the modified electrode was used to detect the presence of metal ions in practical samples and the results obtained are comparatively good with respect to AAS. 相似文献
18.
A Molecular Copper Catalyst for Electrochemical Water Reduction with a Large Hydrogen‐Generation Rate Constant in Aqueous Solution
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Peili Zhang Prof. Mei Wang Yong Yang Tianyi Yao Prof. Licheng Sun 《Angewandte Chemie (International ed. in English)》2014,53(50):13803-13807
The copper complex [(bztpen)Cu](BF4)2 (bztpen=N‐benzyl‐N,N′,N′‐tris(pyridin‐2‐ylmethyl)ethylenediamine) displays high catalytic activity for electrochemical proton reduction in acidic aqueous solutions, with a calculated hydrogen‐generation rate constant (kobs) of over 10000 s?1. A turnover frequency (TOF) of 7000 h?1 cm?2 and a Faradaic efficiency of 96 % were obtained from a controlled potential electrolysis (CPE) experiment with [(bztpen)Cu]2+ in pH 2.5 buffer solution at ?0.90 V versus the standard hydrogen electrode (SHE) over two hours using a glassy carbon electrode. A mechanism involving two proton‐coupled reduction steps was proposed for the dihydrogen generation reaction catalyzed by [(bztpen)Cu]2+. 相似文献
19.
The article describes the use of a fullerene (C60)‐β‐cyclodextrin conjugate, synthesized via 1,3‐dipolar cycloaddition, for the ultrasensitive electrochemical detection of p‐nitrophenol. This conjugate was successfully immobilized on the surface of a glassy carbon electrode and the developed device showed high activity towards p‐nitrophenol due to the synergetic effect of C60, the latter becoming highly conductive upon reduction. The determination of p‐nitrophenol was performed by using square wave voltammetry over a concentration range from 2.8×10?9 mol L?1 to 4.2×10?7 mol L?1 and the detection limit was calculated to be 1.2×10?9 mol L?1. 相似文献
20.
《Electroanalysis》2004,16(23):1992-1998
A carbon nanotubes‐based amperometric cholesterol biosensor has been fabricated through layer‐by‐layer (LBL) deposition of a cationic polyelectrolyte (PDDA, poly(diallyldimethylammonium chloride)) and cholesterol oxidase (ChOx) on multi‐walled carbon nanotubes (MWNTs)‐modified gold electrode, followed by electrochemical generation of a nonconducting poly(o‐phenylenediamine) (PPD) film as the protective coating. Electrochemical impedance measurements have shown that PDDA/ChOx multilayer film could be formed uniformly on MWNTs‐modified gold electrode. Due to the strong electrocatalytic properties of MWNTs toward H2O2 and the low permeability of PPD film for electroacitve species, such as ascorbic acid, uric acid and acetaminophen, the biosensor has shown high sensitivity and good anti‐interferent ability in the detection of cholesterol. The effect of the pH value of the detection solution on the response of the biosensor was also investigated. A linear range up to 6.0 mM has been observed for the biosensor with a detection limit of 0.2 mM. The apparent Michaelis‐Menten constant and the maximum response current density were calculated to be 7.17 mM and 7.32 μA cm?2, respectively. 相似文献