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Journal articles on the topic 'Gold electrode'

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Author: Grafiati
Published: 4 June 2021
Last updated: 20 February 2023

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1

Watanabe, Toshio, Yohei Yamada, Haruhiko Sakuraba, Mikito Yasuzawa, Toshio Takayanagi, and Tomoki Yabutani. "The Hydrophobic Effect on Electrodeposition of Billirubin Oxidase CotA." Advanced Materials Research 1110 (June 2015): 291–94. http://dx.doi.org/10.4028/www.scientific.net/amr.1110.291.

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The hydrophobic effect on electrodeposition of an enzyme CotA was investigated. The CotA was electrodeposited on a gold disc electrode modified with an alkane thiol self-assembled monolayer (SAM). The CotA immobilized hydrophobic SAM gold electrodes exhibited a larger electrochemical activity compared with the hydrophilic SAM and bare electrodes. In particular, large current responses were observed in an ethanethiol or a 1-butanethiol SAM gold electrode. In addition, effect of addition of non-ionic surfactant Triton X on the electrodeposition was checked using the SAM gold electrode. The addition of Triton X had a positive effect on the electrodeposition.
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2

van Megen, M. J. J., W. Olthuis, and A. van den Berg. "Submicron Electrode Gaps Fabricated by Gold Electrodeposition at Interdigitated Electrodes." Key Engineering Materials 605 (April 2014): 107–10. http://dx.doi.org/10.4028/www.scientific.net/kem.605.107.

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Electrodes with submicron gaps are desired for achieving high amplication redoxcycling sensors. In this contribution we report the use of electrodeposition of gold in order todecrease the inter-electrode spacing at interdigitated electrodes. Using this method submicronspacings can be obtained without expensive techniques such as e-beam lithography or focusedion beam milling. Initially, gold interdigitated electrodes with a nger spacing of 2.5 m wererealized by lift-o processing. Using a commercial gold sulphite bath (ECF64D) and 100 mscurrent pulses of -1.78 A, these gold electrodes were plated with an additional gold layer. Asa result, the inter- electrode spacing, as measured using atomic force microscopy and conven-tional microscopy, was reduced to 0.6 m. The achieved gap spacing is limited by electrodeimperfections resulting from the lift-o process. At these imperfections the electrodes becomeshorted. Additional experiments with wet etched electrodes are expected to yield smaller gapspacings
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3

Gnapowski, Sebastian, Elżbieta Kalinowska-Ozgowicz, Mariusz Śniadkowski, and Aleksandra Pietraszek. "Investigation of the Condition of the Gold Electrodes Surface in a Plasma Reactor." Materials 12, no. 13 (July 3, 2019): 2137. http://dx.doi.org/10.3390/ma12132137.

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During the long-term operation of a plasma reactor, decreases in plasma concentration were noticed despite the constant maintenance of all parameters. One of the factors was the decrease in the nitrogen content on the electrode surface; in order to eliminate it, the supply voltage was increased up to 11 kV. Another decisive factor in the plasma concentration decrease was the oxidation of the electrode surface. These effects were studied using two electrodes: a gold one and a copper one coated with a 10 μm thick layer of galvanized gold. In the experiment with the gold coated electrode, a large decrease in plasma concentration was observed. High-energy electrons knocked out the gold atoms from the electrode; as a result, the gold atoms evaporated and the raids layers formed. After the electrodes had been in operation for a month, metallographic analyzes were carried out, the results of which are described in this paper.
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4

Chen, Qiao, Xianhe Huang, Yao Yao, and Kunlei Mao. "Analysis of the Effect of Electrode Materials on the Sensitivity of Quartz Crystal Microbalance." Nanomaterials 12, no. 6 (March 16, 2022): 975. http://dx.doi.org/10.3390/nano12060975.

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This paper investigated the effect of electrode materials on the performance of quartz crystal microbalance (QCM) sensors by means of theoretical calculation, experiment, and finite element analysis methods. First, we calculated the particle displacement amplitude and thus obtained the mass sensitivity function distribution of QCMs with gold, silver and aluminum electrodes, and found that the QCM with the gold electrode has the highest mass sensitivity at the center of the electrode. Then, we tested the humidity-sensing performance of QCMs with gold, silver, and aluminum electrodes using graphene oxide (GO) as the sensitive material, and found that the QCM with the gold electrode has higher humidity sensitivity. Finally, we used the finite element analysis software COMSOL Multiphysics to simulate the specific electrode material parameters that affect the sensitivity of the QCMs. The simulation results show that the density and Young’s modulus of the electrode material parameters mainly affect the sensitivity. The results of this paper are instructive for optimizing QCM sensor performance and improving the capability of QCM quantitative analysis.
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5

Vyas, Ritesh Navneetrai, and Dane Brankle. "Trace Level Quantification of Lead in Michigan Lake Water Using Differential Pulse Stripping Voltammetry: A Comparative Study on the Usage of Mercury Based Electrodes Vs Solid State Gold Electrodes." ECS Meeting Abstracts MA2022-02, no. 60 (October 9, 2022): 2548. http://dx.doi.org/10.1149/ma2022-02602548mtgabs.

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The concentration of lead in fresh-water samples from the southern shoreline of Lake Michigan was analysed and compared using two different cell-stands: Controlled Growth Mercury Electrode (CGME) and voltammetry cell stand with disk type gold electrode. Clearly visible Lead (II) peaks at -395 mV and 130 mV were obtained with CGME and Au electrodes respectively using anodic stripping voltammetry (ASV) technique. Sensitivity, reproducibility, and ease of usage were differentiated for each method. While the measured lead concentration was 2.4 ppb using CGME set-up a closely similar concentration of 2.7 ppb was obtained with the gold disk electrode set-up and thereby confirms the availability of Hg-free detection of lead. The sensitivity obtained from the standard addition curve using the gold electrode was also over twice that of the CGME. The difference in background currents was attributed to the different electrode materials, bulk diffusion in electrolyte of lead ions, electrode-electrolyte interface and the relative surface areas of the electrode surface. Even after repeated polishing of gold electrodes in each run, its inherent sensitivity makes it an ideal candidate for lead determinations with no further requirement of handling the hazardous mercury wastes.
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6

Shi, Qiaofang, Guowang Diao, and Shaolin Mu. "Electrochemical oxidation of glucose on gold nanoparticle-modified reduced graphene oxide electrodes in alkaline solutions." Functional Materials Letters 08, no. 03 (June 2015): 1540004. http://dx.doi.org/10.1142/s1793604715400044.

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A given amount of gold is electrodeposited on the reduced graphene oxide (RGO)/glassy carbon (GC) electrodes to form Au /RGO/GC electrodes, which are carried out at different potentials. The Au /RGO/GC electrode with Au loading of 250 μg cm-2 prepared at a constant potential of -0.30 V exhibits the best electrocatalytic activity to glucose oxidation in alkaline solutions because of homogeneous dispersion of gold nanoparticles with smaller sizes. This electrode shows long-term stability, rapid charge transfer ability, and higher current density compared to other gold electrodes reported previously.
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7

Vyas, Ritesh Navneetrai, Dane Brankle, and Jon Howell. "Trace Analysis of Lead in Michigan Lake Water Using Differential Pulse Stripping Voltammetry: A Comparative Study on the Usage of Controlled Growth Mercury Electrodes Vs Solid State Gold Electrodes." ECS Meeting Abstracts MA2022-01, no. 51 (July 7, 2022): 2439. http://dx.doi.org/10.1149/ma2022-01512439mtgabs.

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The concentration of lead in fresh-water samples from the southern shoreline of Lake Michigan was analyzed and compared using two different cell-stands: Controlled Growth Mercury Electrode (CGME) and voltammetry cell stand with disk type gold electrode. Clearly visible Lead (II) peaks at -395 mV and 130 mV were obtained with CGME and Au electrodes respectively using anodic stripping voltammetry (ASV) technique [1-4]. Sensitivity, reproducibility, and ease of usage are compared and reported for each method. While the measured lead concentration was 2.4 ppb using CGME set-up a closely similar concentration of 2.7 ppb was obtained with the gold disk electrode set-up. The sensitivity obtained from the standard addition curve using the gold electrode was over twice that of the CGME. The difference in background currents was attributed to the different electrode materials, bulk diffusion in electrolyte of lead ions, electrode-electrolyte interface and the relative surface areas of the electrode surface. The main convenience associated with the CGME was the fresh electrode surface provided by each new drop, so no further electrochemical cleaning was needed. However, even after repeated polishing of gold electrodes in each run, its inherent sensitivity makes it an ideal candidate for lead determinations with no further requirement of handling the hazardous mercury wastes. Figure 1
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8

Avramov-Ivic, M., V. Kapetanovic, M. Aleksic, and P. Zuman. "Electroreduction of cefetamet on mercury platinum and gold electrodes." Journal of the Serbian Chemical Society 65, no. 1 (2000): 47–53. http://dx.doi.org/10.2298/jsc0001047a.

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The electroreduction of cefetamet (CEF) using gold and platinum electrodes has been investigated in slightly alkaline medium (pH 8.40) where adsorption, previously observed at mercury electrode, was pronounced. This investigation was performed in order to determine whether the adsorption interfers with the reduction process even at solid electrodes and to compare with a mercury electrode.
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9

Perevezentseva, D. O., and E. V. Gorchakov. "Electrochemical Response of Gold Nanoparticles at a Graphite Electrode." Advanced Materials Research 1040 (September 2014): 297–302. http://dx.doi.org/10.4028/www.scientific.net/amr.1040.297.

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The electrochemical activity of gold nanoparticles at graphite electrodes by the method of cyclic voltammetry is studied. In this article the nature of the supporting electrolyte, modification time of graphite electrode by gold nanoparticles and the potential range on the value of the “inverse” cathodic peak are investigated. The “inverse” cathodic peak of gold nanoparticles formed in the reaction mixture HAuCl4:Na3C6H5O7:NaBH4=1:1:4 is observed on the cathodic branch of cyclic voltamperegram at Ec = 0.05 V at graphite electrode. The mechanism of stepwise electrochemical oxidation and reduction of the phase structure of gold on the surface of the graphite electrode in 0.1 M NaOH is offered. The “inverse” cathodic peak of gold nanoparticles on the cathodic branch of cyclic voltammogram at graphite electrode is caused by oxidation of Au2O to Au2O3.<br /><br />
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10

Emdadi, Arash, Julie N. Renner, and Lauren F. Greenlee. "Nitrate Reduction By Hydrophobic, Negatively, and Positively Charged Peptide-Coated Au Electrode." ECS Meeting Abstracts MA2022-01, no. 40 (July 7, 2022): 1800. http://dx.doi.org/10.1149/ma2022-01401800mtgabs.

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Nitrate has been considered as a source of water pollution with harmful effects on human health. Compared to other removal techniques, electrochemical reduction of nitrate is capable of delivering products such as ammonia and nitrogen which are valuable and harmless, respectively. However, it is challenging to control nitrate reduction pathway through catalyst design alone. Our research goal in this work is to understand how peptide chemistry influences nitrate reduction pathway and electrocatalyst activity for a suite of peptide-functionalized electrocatalyst surfaces. To analyze the electrocatalytic reduction of nitrate, three types are peptides, including V (hydrophobic), E (negatively charged), and K (positively charged), were coated on the gold electrodes and their performance compared with the bare gold electrode. In all the experiments, the effective area of the Au electrode was 1 cm2. An electrochemical cell with the gold electrode (working electrode), platinum (counter electrode) electrode, and a background solution (0.5 M Na2SO4) were used for electrochemical experiments. Cyclic voltammetry (CV) was used to assess the reduction of nitrate by different peptide-coated Au electrodes in the presence of nitrate ions (0.5 M Na2SO4 +0.1 M NaNO3, pH∼7.1), with a scanning rate of 20 mV/s. Chronoamperometry (CA) was applied to investigate the conversion of nitrate to different products and the pathway of nitrate reduction at different operational conditions. UV–visible spectrophotometry was employed to analyze the conversion of nitrate into nitrite and ammonia in the solution. Results of CV indicate that gold electrodes coated with V and E type peptides have promising responses to the applied voltage in the presence of nitrate ions. Based on the results, reduction of nitrate takes place at the onset potentials of -0.37 V and -0.23 V versus reversible hydrogen electrode (RHE) for E and V types of peptide-coated Au electrodes, respectively. To assess the pathway of nitrate reduction, CA experiments were done for 60 minutes on the hydrophobic peptide-coated Au and bare Au electrodes by applying a constant potential of -0.37 V versus RHE. Initial CA results of the V peptide coated-Au electrode indicate the reduction of nitrate into both nitrite and ammonia compared to a bare gold electrode which is only capable of nitrate reduction to ammonia. Based on the initial results, 0.92 mg ammonia, and 0.78 mg nitrite were produced by a V-type coated-Au electrode after 60 minutes CA experiment.
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11

Angel, S. M., L. F. Katz, D. D. Archibald, L. T. Lin, and D. E. Honigs. "Near-Infrared Surface-Enhanced Raman Spectroscopy. Part I: Copper and Gold Electrodes." Applied Spectroscopy 42, no. 8 (November 1988): 1327–31. http://dx.doi.org/10.1366/0003702884429698.

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Surface-enhanced Raman spectra of pyridine on copper and gold electrodes in the near-infrared were obtained with a Fourier transform Raman spectrometer. Surface-enhanced Raman spectra were observed for pyridine adsorbed on copper and gold electrodes while a Nd:YAG laser (1.064/μm) was used for excitation. Good-quality spectra were recorded for 0.08 mM pyridine on a copper electrode with a single oxidation-reduction cycle, whereas for a gold electrode, several ORCs were necessary. A very intense low-energy Raman band was observed on both metals at positive potentials, which may be due to a metal-oxide vibrational mode.
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12

Lim, Jaemook, Jimin Ham, Woohyun Lee, Eunseung Hwang, Won Chul Lee, and Sukjoon Hong. "A Transformative Gold Patterning through Selective Laser Refining of Cyanide." Nanomaterials 11, no. 8 (July 26, 2021): 1921. http://dx.doi.org/10.3390/nano11081921.

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Gold is an essential noble metal for electronics, and its application area is increasing continuously through the introduction of gold nanoparticle ink that enables rapid prototyping and direct writing of gold electrodes on versatile substrates at a low temperature. However, the synthesis of gold nanoparticles has certain limitations involving high cost, long synthesis time, large waste of material, and frequent use of chemicals. In this study, we suggest simultaneous laser refining of gold cyanide and selective fabrication of gold electrodes directly on the substrate without a separate synthesis step. Gold cyanide is commonly the first product of gold from the primitive ore, and the gold can be extracted directly from the rapid photothermal decomposition of gold cyanide by the laser. It was confirmed that laser-induced thermocapillary force plays an important role in creating the continuous gold patterns by aligning the refined gold. The resultant gold electrodes exhibited a low resistivity analogous to the conventional direct writing method using nanoparticles, and the facile repair process of a damaged electrode was demonstrated as the proof-of-concept. The proposed transformative approach for gold patterning, distinguished from the previous top-down and bottom-up approaches, has the potential to replace the well-known techniques and provide a new branch of electrode manufacturing scheme.
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13

Straßer, Torsten, Susanne Kramer, Melanie Kempf, Tobias Peters, Anne Kurtenbach, and Eberhart Zrenner. "Visual Evoked Potentials Used to Evaluate a Commercially Available Superabsorbent Polymer as a Cheap and Efficient Material for Preparation-Free Electrodes for Recording Electrical Potentials of the Human Visual Cortex." Sensors 19, no. 22 (November 9, 2019): 4890. http://dx.doi.org/10.3390/s19224890.

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The aim of this study was to investigate the use of inexpensive and easy-to-use hydrogel “marble” electrodes for the recording of electrical potentials of the human visual cortex using visual evoked potentials (VEPs) as example. Top hat-shaped holders for the marble electrodes were developed with an electrode cap to acquire the signals. In 12 healthy volunteers, we compared the VEPs obtained with conventional gold-cup electrodes to those obtained with marble electrodes. Checkerboards of two check sizes—0.8° and 0.25°—were presented. Despite the higher impedance of the marble electrodes, the line noise could be completely removed by averaging 64 single traces, and VEPs could be recorded. Linear mixed-effect models using electrode type, stimulus, and recording duration revealed a statistically significant effect of the electrode type on only VEP N75 peak latency (mean ± SEM: 1.0 ± 1.2 ms) and amplitude (mean ± SEM: 0.8 ± 0.9 µV) The mean amplitudes of the delta, theta, alpha, beta, and gamma frequency bands of marble electrodes were statistically significantly different and, on average, 25% higher than those of gold-cup electrodes. However, the mean amplitudes showed a statistically significant strong correlation (Pearson’s r = 0.8). We therefore demonstrate the potential of the inexpensive and efficient hydrogel electrode to replace conventional gold-cup electrodes for the recording of VEPs and possibly other recordings from the human cortex.
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14

Foguel, Marcos Vinicius, Carolina Venturini Uliana, Paulo Roberto Ussoni Tomaz, Paulo Roberto Brasil De Oliveira Marques, Hideko Yamanaka, and Antonio Aparecido Pupim Ferreira. "Avaliação da limpeza de CDtrodo construídos a partir de CD de ouro gravável/fita adesiva de galvanoplastia." Eclética Química Journal 34, no. 2 (January 24, 2018): 59. http://dx.doi.org/10.26850/1678-4618eqj.v34.2.2009.p59-66.

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Gold electrodes are widely used in electrochemistry and electroanalytical chemistry, due to the high purity, broad range of work potential as well as the possibility to control and modify the surface. On this work construction and cleaning of electrodes from gold recordables compact discs (CD-Rs), namely CDtrodes, are described. The CDs was submitted to the action of concentrated HNO3 in order to remove the protection layer and to expose the metallic layer; the electrode area was delimited by using galvanoplasty tape. The literature has been published many articles on CDtrode focused on the application but not on the cleaning; there is no register on galvanoplasty tape to define electrode area. Several methods for gold surface cleaning after attack of HNO3 were investigated, such as application of fixed potential in NaClsolution, successive scans in H2SO4 and ultrasound application, and best results were obtained in H2SO4 solution. This electrode material is interesting due to the performance comparable to the commercial electrodes, besides great versatility and low cost.
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15

Tortolini, Cristina, Federico Tasca, Mary Anna Venneri, Cinzia Marchese, and Riccarda Antiochia. "Gold Nanoparticles/Carbon Nanotubes and Gold Nanoporous as Novel Electrochemical Platforms for L-Ascorbic Acid Detection: Comparative Performance and Application." Chemosensors 9, no. 8 (August 16, 2021): 229. http://dx.doi.org/10.3390/chemosensors9080229.

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Herein, the effects of nanostructured modifications of a gold electrode surface in the development of electrochemical sensors for L-ascorbic acid detection have been investigated. In particular, a bare gold electrode has been modified by electrodeposition of gold single-walled carbon nanotubes (Au/SWCNTs) and by the formation of a highly nanoporous gold (h-nPG) film. The procedure has been realized by sweeping the potential between +0.8 V and 0 V vs. Ag/AgCl for 25 scans in a suspension containing 5 mg/mL of SWCNTs in 10 mM HAuCl4 and 2.5 M NH4Cl solution for Au/SWCNTs modified gold electrode. A similar procedure was applied for a h-nPG electrode in a 10 mM HAuCl4 solution containing 2.5 M NH4Cl, followed by applying a fixed potential of −4 V vs. Ag/AgCl for 60 s. Cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the properties of the modified electrodes. The developed sensors showed strong electrocatalytic activity towards ascorbic acid oxidation with enhanced sensitivities of 1.7 × 10−2 μA μM−1cm−2 and 2.5 × 10−2 μA μM−1cm−2 for Au/SWCNTs and h-nPG modified electrode, respectively, compared to bare gold electrode (1.0 × 10−2 μA μM−1cm−2). The detection limits were estimated to be 3.1 and 1.8 μM, respectively. The h-nPG electrode was successfully used to determine ascorbic acid in human urine with no significant interference and with satisfactory recovery levels.
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16

Oliveira, Thalyta Pereira, Suely Moura Melo, Semirames Jamil Hadad do Monte, Ruan Sousa Bastos, Ionara Nayana Gomes Passos, Adalberto Socorro Silva, and José Ribeiro dos Santos Júnior. "Development of electrochemical biosensor: Voltammetric analysis of lymphocytes and indication activation of complement system." Research, Society and Development 11, no. 7 (June 5, 2022): e59611730198. http://dx.doi.org/10.33448/rsd-v11i7.30198.

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This work reports the development of an electrochemical biosensor after immobilization of the lymphocytes to detect the reaction between antibodies and specific HLA antigens present in the serum samples. A clean homemade gold electrode with voltammetric polycrystalline characteristics was used. Lymphocytes were immobilized and tested with positive and negative human serum and complements on the gold electrode. The experiments were carried out in a cell with three electrodes: working - gold, reference - Ag/AgCl/sat. KCl and auxiliary - platinum. The cyclic voltammetric analyses of immobilized lymphocytes on the gold surface presented anodic current equal to 1.78 μA at c.a. 0.50 V vs. Ag/AgCl/sat. KCl. The electrochemical responses of the serum (positive and negative) and complement do not show signs of oxidation or reduction in the potential range used. The electrodes with cells and positive serum showed the amplified current signal in the oxidation potential of the cells. The electrode was developed to verify the antigen antibody reaction, present lymphocyte cell and human serum samples. The electrode was qualitatively efficient when compared to the methods of flow cytometric analysis and complement dependent cytotoxicity, being able to be used with operational and economic advantages.
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17

Al Mamun, Mohammad, Yasmin Abdul Wahab, Hossain Hossain, Abu Hashem, and Mohd Rafie Johan. "Scrap Gold Recovery: Recycling, Fabrication and Electrochemical Characterization of Low-Cost Gold Electrode." Malaysian Catalysis-An International Journal 2, no. 1 (October 21, 2022): 1–20. http://dx.doi.org/10.22452/mcij.vol2no1.1.

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As a noble metal, gold is considered the most popular material in electrocatalysis. In spite of that, this metal is a highly expensive material in the manufacture of low-cost appliances. In the present work, scrap gold, produced in jewellery as waste, is introduced as a low-cost resource of gold to be recycled. A gold electrode was fabricated by connecting the tablet shaped recycled gold with copper wire inserting into a polytetrafluoroethylene (PTFE) tube. The manufactured electrodes are easily renewable, modifiable with nanomaterials and show excellent electrochemical characteristics in presence of redox species. The CV (cyclic voltammetry), DPV (differential pulse voltammetry), and EIS (electrochemical impedance spectroscopic) analysis data also infer that the developed recycled gold-based electrodes would be suitable for the development of low-cost electrocatalytic sensors devices.
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18

Shah, Anwar ul Haq Ali, Sadaf Zia, Gul Rahman, and Salma Bilal. "Performance Improvement of Gold Electrode towards Methanol Electrooxidation in Akaline Medium: Enhanced Current Density Achieved with Poly(aniline-co-2-hydroxyaniline) Coating at Low Overpotential." Polymers 14, no. 2 (January 13, 2022): 305. http://dx.doi.org/10.3390/polym14020305.

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Electronically conducting poly (aniline-co-2-hydroxyaniline) (PACHA), a copolymer of aniline and 2-hydroxyaniline (2HA), was electrochemically coated on gold substrate for methanol electrooxidation in alkaline media. The electrochemical behavior of PACHA coated gold electrode towards methanol electrooxidation was investigated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) for application in an alkaline fuel cell. Methanol electrooxidation was observed at two different electrode potentials depending on the concentration of the base. At the PACHA coated gold electrode, the methanol oxidation peak was observed at lower overpotential (at 0.19 V) in a solution of high base concentration (1.8 M NaOH), which was 30 mV lower than the peak for the uncoated gold electrode. In addition, the Faradic current Imax obtained on the PACHA coated electrode (20 mA) was two times higher as compared to the Faradic current Imax of the un-modified gold electrode (10 mA). In solution of lower base concentration (0.06 M NaOH), the electrooxidation of methanol became sluggish on both electrodes, as indicated by peak shifting towards positive potential and with reduced faradaic current (at 0.74 V on PACHA coated electrode; Imax 10 mA). The electrooxidation of methanol at both lower and higher electrode potentials was analyzed mechanistically and discussed in light of the literature. EIS results were interpreted using Nyquist and Bode plots. The charge transfer resistance was decreased and pseudo-capacitive behavior changed to conductive behavior when external applied potential was increased from 0.1 V to 0.4 V.
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19

Fakhrabadi, N. H., A. A. Rohani, and Afshin Farahbakhsh. "Modification of Glucose Oxides Sensors Using Colloidal Gold Nanoparticles." Advanced Materials Research 496 (March 2012): 17–20. http://dx.doi.org/10.4028/www.scientific.net/amr.496.17.

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Glucose oxidase sensor is one of the best methods for measuring small amounts of glucose; this sensor can be modified using colloidal gold nanoparticles as complementary substance in the electrode structure with the aim of increasing efficiency. In this article, the colloidal gold nanoparticles (24 nm) were used to construct the two electrodes. The first electrode (Au/CP) was constructed of 100 mg carbon graphite powder, 36 µl paraffin oil and 300 µl colloidal gold nanoparticles. The second electrode (Au/CILE) was constructed of 100 mg carbon graphite powder, 36 µl paraffin oil, 300 µl colloidal gold and 50 mg ionic liquid oppf6. To evaluate the performance of each electrode and to prepare of bio sensor, these were covered by solution of 10 mg glucose oxidase and 1 ml phosphate buffer. The bio sensors were test with 0.8 mM glucose solution. By comparing the amount of AMP and the transfer time for both, the according results, the effect of colloidal gold nanoparticles on the increasing conductivity, sensitivity and stability biosensor, was determined.
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20

Buckey, Grace, Olivia E. Owens, Ainslee W. Gabriel, Claudia M. Downing, Margaret C. Calhoun, and David E. Cliffel. "Adsorption and Electropolymerization of p-Aminophenol Reduces Reproducibility of Electrochemical Immunoassays." Molecules 27, no. 18 (September 16, 2022): 6046. http://dx.doi.org/10.3390/molecules27186046.

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This paper investigates the electrochemical behavior of p-aminophenol (PAP) on commercially available carbon screen-printed electrodes (CSPEs) and gold screen-printed electrodes (GSPEs) at neutral and basic pHs for the development of inexpensive immunoassays. The electrochemical oxidative signal from PAP results from its adsorption to the electrode. The formation of self-assembled monolayers on gold electrodes prevented PAP adsorption but also reduced its oxidative current, confirming that adsorption increases signal production. On bare electrodes, PAP adsorption results in oxidative current variability depending on the electroactive surface area of the screen-printed electrode. This variability could not be remedied by cleaning and reusing the same GSPE. Decreasing the PAP concentration to 3.8 μM greatly improved the consistency of the measurements, suggesting that the adsorption of PAP is concentration-dependent. Multiple PAP oxidations on the same electrode caused polymerization, limiting PAP in continuous monitoring applications. Infrared and Raman spectroscopy allow the distinction between adsorbed PAP and electropolymerized PAP on the surface of a gold wafer. The results from this study suggest that the use of PAP production in immunoassays with SPEs must be fine-tuned, and electrodes must be cleaned or disposed of between measurements.
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21

Govor, L. V., and J. Parisi. "Conductance Fluctuations in Chains of Particles Arising from Conformational Changes of Stabilizer Molecules." Zeitschrift für Naturforschung A 68, no. 1-2 (February 1, 2013): 157–64. http://dx.doi.org/10.5560/zna.2012-0076.

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We have bridged a pair of gold electrodes with various arrangements of gold nanoparticles stabilized with citrate molecules. The resulting devices exhibited current fluctuations at a constant bias voltage and fluctuations of the differential conductance as a function of the bias voltage. These fluctuations were attributed to the interplay of molecular conformation, charge switching, and breaking of the links at the interface molecules-electrode. We found that, for all investigated samples, the contact resistance at the interface molecules-electrode was by about one order of magnitude larger than that between nanoparticles coupled by citrate molecules. We conclude that the mechanism of charge transport can be viewed as a series of discrete steps involving initial hopping (injection) of the charge from the left-hand-side gold electrode to the molecules, tunnelling of the charge through the molecules-nanoparticle-molecules (MNM) unit, hopping to the next MNM unit, etc., and finally hopping (extraction) of the charge to the right-hand-side gold electrode.
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22

Ruiz, Gabriel A., Martín L. Zamora, and Carmelo J. Felice. "Isoconductivity method to study adhesion of yeast cells to gold electrode." Journal of Electrical Bioimpedance 5, no. 1 (August 8, 2019): 40–47. http://dx.doi.org/10.5617/jeb.809.

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AbstractIn this paper, we used impedance spectroscopy and gold electrodes to detect the presence of yeast cells and monitor the attachment of these cells to the electrodes. We analyzed the effect of conductivity changes of the medium and the attachment on the electrode-electrolyte interface impedance. A three-electrode cell was designed to produce a uniform electric field distribution on the working electrode and to minimize the counter electrode impedance. Moreover, we used a small AC overpotential (10 mV) to keep the system within the linear impedance limits of the electrode-electrolyte interface. This study proposes a new method to differentiate the impedance changes due to the attachment of yeast cells from those due to conductivity changes of the medium. The experiments showed that when the difference between the cell suspension and base solution conductivities is within the experimental error, the impedance changes are only due to the attachment of yeast cells to the electrodes. The experiments also showed a strong dependence (decrease) of the parallel capacity of the electrode electrolyte interface with the yeast cell concentration of suspension. We suggest that this decrease is due to an asymmetrical redistribution of surface charges on both sides of cell, which can be modeled as a biologic capacity connected in series with the double layer capacity of the interface. Our results could help to explain the rate of biofilm formation through the determination of the rate of cell adhesion.
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Liu, Xue Ping, Hai Yan Kang, Wei Hua Chang, and Min Ma. "Electrocatalytic Oxidation of Nitrite on Poly-Thionine/gold Nanoparticles Composites Modified Glassy Carbon Electrode." Advanced Materials Research 512-515 (May 2012): 2295–99. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.2295.

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This paper describes the electrocatalytic oxidation of nitrite by poly-thionine /gold nanoparticle modified glassy carbon electrode. Due to the synergistic effect of poly-thionine and gold nanoparticle, the modied electrodes could oxide nitrite with enhanced oxidation current and a decrease in the required overpotential compared with bare electrode without poly-thionine and gold nanoparticles layer coated. The influence factors for nitrite assay such as polymer film thickness, adsorption time of gold nanoparticles onto the poly-thionine film, different buffers and pH，interferent ions were discussed elaborately. Under the optimal conditions, the oxidation current signal was proportional to the concentration of nitrite from 3.0×10-6 to 1.0×10-3 mol/L with a detection limit of 1.0×10-6 mol/L. The proposed method has been applied to determine nitrite concentration in real samples and the results were satisfactory. The poly-thionine/gold nanoparticles composites modied electrode has been proved to possess high sensitivity, good storage stability, reproducibility and anti-interference ability.
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24

Hamagami, Jun Ichi, Kazuhiro Hasegawa, and Kiyoshi Kanamura. "Micropattern of Colloidal Crystal by Using Electrophoretic Deposition Process with Three-Electrode System." Key Engineering Materials 320 (September 2006): 171–74. http://dx.doi.org/10.4028/www.scientific.net/kem.320.171.

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A novel micropatterning process for a particle assembly has been performed by using an electrophoretic deposition (EPD) method with a local electric field in a colloidal suspension generated by a three-electrode system. Monodisperse silica colloidal spheres with a diameter of 300 nm were used to fabricate micropattern of colloidal crystal. An interdigitated gold-microarray electrode with a 10 μm of width and a gold plate electrode were used as the working and the counter electrodes, respectively. After optimization of the EPD processing parameters, a micropattern was constructed from silica colloidal spheres. It had a relatively close-packed structure formed onto the interdigitated microarray electrode. This micropattern showed a characteristic optical reflectance peak due to Bragg’s law.
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25

MIAO, YUQING, JIANRONG CHEN, XIAOHUA WU, and KEMING FANG. "THE ELECTROCHEMICAL STUDY OF SELF-ASSEMBLED 1,3-PROPANEDITHIOL ON GOLD." Surface Review and Letters 14, no. 01 (February 2007): 111–15. http://dx.doi.org/10.1142/s0218625x07009128.

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The electrochemical behaviors of bare/dithiol-modified gold electrode were studied in the PBS solution with/without dithiols. A pair of current peaks between -1.4 and -0.5 V is related to dithiol adsorption or re-adsorption. An oxidative peak at 0.37 V accompanied by a slight peak at 0.03 V is observed between -0.5 and 0.7 V for the bare gold electrode in the thiol solution, which is due to the formation of bilayer. When the potential is scanned to a very positive value at 1.2 V, a new oxidative peak at 1.07 V appears for the bare gold electrode in the dithiol solution or the PBS solution. The assembled dithiols are desorbed, and gold surface is exposed. The study indicates that the 1,3-propanedithiol modified electrodes should be used during the potential range of -0.8 to 0.8 V to keep the assembled layer stable.
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26

Osornio, Azucena, Luis A. García, Leonor M. Blanco, Rene Antaño, and Federico Castañeda. "Electrochemical Impedance Spectrocopy Study Of Glucose Adsorption On Gold Nanoparticles-Graphite Paste Electrode." MRS Advances 2, no. 49 (2017): 2713–20. http://dx.doi.org/10.1557/adv.2017.535.

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ABSTRACTElectrochemical Impedance Spectroscopy (EIS), is a confirmed tool for investigation of electrode/electrolyte interfaces and surface-modified electrodes. In the present work, we apply this approaching way to obtain a deeper insight into the electrochemical oxidation mechanism of the glucose in alkaline media. We studied the EIS response of gold nanoparticles embedded in carbon paste and use it as an electrode for the electro-oxidation of glucose. The results were compared with those of a polycrystalline gold electrode. In order to determine the polarization potentials for EIS tests, cyclic voltammetry is first conducted in 0.3 M KOH with 10 mM glucose, recorded at a scan rate of 1 mVs-1. Three polarization potentials were chosen, corresponding to: the open circuit potential (OCP), glucose oxidation and gold oxide formation respectively.
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27

Fitriyana, Fitriyana, and Fredy Kurniawan. "Polyaniline-Invertase-Gold Nanoparticles Modified Gold Electrode for Sucrose Detection." Indonesian Journal of Chemistry 15, no. 3 (November 12, 2015): 226–33. http://dx.doi.org/10.22146/ijc.21189.

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Sucrose sensor has been made by deposited the active materials on the surface of gold electrode. The active materials, i.e. polyaniline (PANI), invertase and gold nanoparticles, were deposited step by step. Aniline polymerization were conducted electrochemically at potential -500 to 1000 mV using voltammetry method with sweep rate 50 mV/s for 20 cycles in HCl solution pH 1.5. The modified electrode obtained was immersed in invertase 1 M phosphate buffer solution pH 6. The invertase trapping in polyaniline was performed using the same condition as aniline polymerization. Then, gold nanoparticles were deposited on the polyaniline-invertase modified gold electrode using Layer by Layer (LbL) technique. The polyaniline-invertase-gold nanoparticles modified gold electrode obtained was used to measure sucrose solution. Electrochemical signal of polyaniline (PANI)-invertase-gold nanoparticles modified gold electrode is increase with sucrose concentration. The sensitivity and detection limit of the electrode are 0.4657 µA mm-2 mM-1 and 9 µM, respectively. No electrochemical interference signals from fructose and glucose have been observed in the sucrose measurement.
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28

Fujihira, M., H. Muraki, and S. Aoyagui. "An alkylsilanized gold electrode." Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 195, no. 1 (November 1985): 197–201. http://dx.doi.org/10.1016/0022-0728(85)80019-x.

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29

Watoni, Abdul Haris, Indra Noviandri, Muhammad Nurdin, and La Ode Ahmad Nur Ramadhan. "Electrocoating Polypyrrole on Gold-Wire Electrode as Potential Mediator Membrane Candidate for Anionic Surfactant Electrode Sensor." Jurnal Kimia Sains dan Aplikasi 23, no. 5 (May 7, 2020): 167–76. http://dx.doi.org/10.14710/jksa.23.5.167-176.

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The development of polypyrrole as a potential mediator membrane candidate for sodium dodecyl sulfate (SDS) sensor electrode has been investigated. The polypyrrole membrane was synthesized electrochemically from the pyrrole and coated at the surface of a 1.0 mm diameter of the gold-wire electrode. Electropolymerization of pyrrole and coating of the polypyrrole produced was performed by cyclic voltammetry technique in the electrochemical cell containing supporting electrolyte of 0.01 M NaClO4 with an optimum potential range of -0.9 V–1.0 V, the scanning rate of 100 mV/s, an electric current of 2 mA, and running of potential scanning of 10 cycles. By using the similar optimal parameters of cyclic voltammetry, electropolymerization of 0.01 M pyrrole solution containing 0.001 M SDS also produces a polypyrrole membrane coated at the gold-wire electrode surface. These coated electrodes have the potential response-ability toward DS- anions in the concentration range of 10-7 M–10-5 M with a limit of detection of 10-7 M and sensitivity of electrode of 9.9 mV/decade. This finding shows that the SDS solution’s role is as supporting electrolyte and also as a source of DS- dopant during the pyrrole electropolymerization processes. Dopants are trapped in the polymer membrane during the electrochemical formation of polypyrrole and role as ionophores for DS- anion in the analyte solution. A potential response to the electrode phenomena is excellent basic scientific information for further synthesis of conducting polymer and development of conducting polymer-coated wire electrode model, especially in the construction of ion-selective electrode (ISE) for the determination of anionic surfactants with those models.
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30

Ndiaye, Amadou L., Alain Pauly, Sebastien Delile, Jérôme Brunet, Christelle Varenne, and Abhishek Kumar. "Electrodes Modification Based on Metal-Free Phthalocyanine: Example of Electrochemical Sensors for the Detection of Acetic Acid." Journal of Sensors 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/290598.

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Electroanalytical properties of tetra-tert-butyl phthalocyanine (PcH2-tBu) modified electrodes are studied by cyclic voltammetry (CV). The modified electrodes are obtained by CV deposition techniques on gold (Au) and glassy carbon (C) screen-printed electrodes (SPEs) and used for the electrochemical detection of acetic acid (AA). Based on the CV experiments, the electrodeposition mechanism is detailed. The modified PcH2-tBu electrodes reveal one oxidation and one reduction peak within the potential window of the working electrodes. In the presence of the analyte (acetic acid), the modified electrodes show sensitivity in the range of 10 mM to 400 mM. For the PcH2-tBu modified Au electrode, a limit of detection (LOD) of 5.89 mM (based on the +0.06 V peak) was obtained while for the PcH2-tBu modified C electrode a LOD of 17.76 mM (based on the +0.07 V peak) was achieved. A signal decay of 17%, based on 20 experiments, is obtained when gold is used as working electrode. If carbon is used as working electrode a value of 7% is attained. A signal decay is observed after more than 50 cycles of experiments and is more pronounced when higher concentrations of acetic acid are used. A mechanism of sensing is proposed at the end.
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31

Sun, Ying Ying, Shuang Zhao, and Qun Xiang Ren. "Glucose Biosensor Based on Immobilization of Glucose Oxidase on Silica Nanoparticles Modified Au Electrode." Advanced Materials Research 503-504 (April 2012): 424–27. http://dx.doi.org/10.4028/www.scientific.net/amr.503-504.424.

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A feasible method to fabricate glucose biosensor was developed by covalent attachment of glucose oxidase (GOx) to a silica nanoparticle monolayer modified gold electrode. Electrochemical impedance spectroscopy (EIS) of ferrocyanide followed the assembly process and verified the successful immobilization of GOx on silica nanoparticle modified on gold electrodes. Cyclic voltammetry (CV), performed in the presence of excess glucose and artificial redox mediator (ferrocenemethanol), allowed to quantify the surface concentration of electrically wired enzyme. The signal of proposed electrode was more than 2.5 times of that on electrode lacking silica nanoparticles. As a result, silica nanoparticles are a good biocompatible solid support for enzyme immobilization.
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32

Heduit, A., B. Martin, I. Duchamp, and D. R. Thevenot. "Comparison of Gold and Platinum Electrode Responses in Activated Sludge." Water Science and Technology 28, no. 11-12 (December 1, 1993): 473–80. http://dx.doi.org/10.2166/wst.1993.0687.

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Gold and platinum were compared to ascertain how they expressed a stabilized potential in activated sludge. The comparison was based on electrochemical determination of the electron transfer rate (i.e. equilibrium exchange current density) and recording of potentials against time. When both metals are treated in the same way, platinum gives equilibrium exchange current densities approx. 10 times higher than gold, both in aerated activated sludge and in treated water. For platinum, the equilibrium exchange current densities range from 0.1 to 0.25 µA/cm2 immediately after polishing and decrease during prolonged contact with activated sludge subjected to alternating aeration/anoxia sequences. The lower kinetics of electron transfer on gold go together with significant differences in response:- In an aerobic medium a gold electrode potential is lower than that of a platinum electrode. In a strongly anaerobic medium, the reverse is true. Consequently, the amplitude of the potential variation between aerobic and anaerobic media is smaller for gold than for platinum. Under our experimental conditions this amplitude was approx 350 mV for gold and 850 mV for platinum.- The slopes of the linear relationships between potential and pH or potential and the logarithm of the dissolved oxygen concentration are two or three times greater for platinum than for gold. Although the values obtained with platinum electrodes cannot represent a veritable equilibrium state, the platinum electrode zero-current potential would seem to be far more sensitive to variations in the medium than that of the gold electrode; it is, therefore, more suitable for use in activated sludge.
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33

Sahatiya, Parikshit, and Sushmee Badhulika. "One-step in situ synthesis of single aligned graphene–ZnO nanofiber for UV sensing." RSC Advances 5, no. 100 (2015): 82481–87. http://dx.doi.org/10.1039/c5ra15351d.

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34

Mustafa, Damra E., Hua Fan, Xuan Zhou, Hai Yang Tu, and Ai Dong Zhang. "Adsorption Behaviour of PEGylated Gold Nanoparticles to Different Surfaces Probed by CV Monitoring." Advanced Materials Research 455-456 (January 2012): 689–95. http://dx.doi.org/10.4028/www.scientific.net/amr.455-456.689.

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Non-adsorption of water dispersible gold nanoparticles (GNPs) is a major concern in its widely labeling applications. This paper presents the investigation of the adsorption properties of GNPs with superficially tethered ferrocene functions to different surfaces. The GNPs were coated with a mixed monolayer of PEG-thiol and progargyl PEG-thiol, and the later was linked with a ferrocene moiety (Fc) through the alkyne-azide click reaction. The adsorption behaviors of the Fc-GNP to glassy carbon, gold and platinum electrodes, in the absence and presence of a self-assembled monolayer (SAM) or protein layer, were studied by cyclic voltammetry (CV). It was found that the bare gold electrode possessed higher adsorption capacity. However, the adsorption was either reduced or completely prevented when the gold electrode was modified with monolayers of 2-mercaptoethanol (ME), dodecanethiolate (DT) and PEG-thiol. The electroactive and water dispersible GNPs with Fc labels allows us to use CV to explore the interaction between these GNP and bovine serum albumin (BSA). The BSA modified electrode resulted in better resistant to adsorption compared to other modifiers coated electrodes. Thus, the study of non-specific interaction by CV was found effective when compared to results obtained by surface plasmon resonance (SPR) and FTIR.
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35

Lannelli, Anna, Jacek Lipkowski, Alexandre G. Brolo, and Donald E. Irish. "Electrochemical and Raman spectroscopic studies of pyrazine adsorption at the Au(210) electrode surface." Canadian Journal of Chemistry 75, no. 11 (November 1, 1997): 1694–702. http://dx.doi.org/10.1139/v97-202.

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Chronocoulometry and Raman spectroscopy have been applied to study pyrazine adsorption at the Au(210) electrode surface. The adsorption isotherms, Gibbs energies of adsorption, and the electrosorption valency for pyrazine adsorption at the Au(210) electrode surface have been determined. Surface-enhanced Raman Scattering (SERS) spectra of pyrazine adsorbed on an "unroughened" Au(210) electrode surface have been obtained for the first time. The thermodynamic data and the SERS spectra indicate that pyrazine adsorbs on the Au(210) electrode via the nitrogen lone pair (N-bonded configuration) over the whole range of electrode potentials investigated. Consequently, the pyrazine molecule assumes only the vertical orientation at this surface of gold. The adsorption of pyrazine at the Au(210) and Au(111) surfaces is compared and the influence of the surface crystallography on the adsorption of this molecule at gold electrodes is discussed. Keywords: adsorption at Au(210), pyrazine, SERS, chronocoulometry.
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36

Pastre, Aymeric, Alexandre Boé, Nathalie Rolland, and Rémy Bernard. "All-Solid-State Interdigitated Micro-Supercapacitors Based on Porous Gold Electrodes." Sensors 23, no. 2 (January 5, 2023): 619. http://dx.doi.org/10.3390/s23020619.

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Recent developments in embedded electronics require the development of micro sources of energy. In this paper, the fabrication of an on-chip interdigitated all-solid-state supercapacitor, using porous gold electrodes and a PVA/KOH quasisolid electrolyte, is demonstrated. The fabrication of the interdigitated porous gold electrode is performed using an original bottom-up approach. A templating method is used for porosity, using a wet chemistry process followed by microfabrication techniques. This paper reports the first example of an all-gold electrode micro-supercapacitor. The supercapacitor exhibits a specific capacitance equal to 0.28 mF·cm−2 and a specific energy of 0.14 mJ·cm−2. The capacitance value remains stable up to more than 8000 cycles.
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37

Armstrong, W. "Polarographic oxygen electrodes and their use in plant aeration studies." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 102 (1994): 511–27. http://dx.doi.org/10.1017/s0269727000014548.

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SynopsisThe electrolytic reduction of oxygen which occurs at a wetted ‘unattackable’ cathodic electrode of platinum or gold when polarised in conjunction with a Ag/AgCl anode, forms the basis of most polarographic oxygen measurements in plant biological work.Various types of polarographic electrode and their uses are reviewed. These include cylindrical sleeving electrodes for quantifying localised oxygen fluxes from intact roots, ‘bare’, membrane-coated, and Clark-type microelectrodes suitable for measuring concentrations and profiles both inside roots and in the rhizosphere, and macro-Clark electrodes most frequently used in respiratory studies.Some details concerning equipment and electrode construction are given and some pitfalls in electrode application are discussed.
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38

Ma, Cheng, Jin Zhu, Xiaolong Li, and Wei Zheng. "Design of a Dual-Technology Fusion Sensor Chip with a Ring Electrode for Biosensing Application." Micromachines 10, no. 2 (February 23, 2019): 153. http://dx.doi.org/10.3390/mi10020153.

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Quartz crystal microbalance (QCM) is still a new high-precision surface detection technique. However, the adsorption quality detected by the QCM currently contains a solvent-coupling quality and cannot separate the actual biomolecular mass. Local surface plasmon resonance (LSPR) can detect the mass of biomolecules, but requires a certain contrast between the solvent of the surrounding medium and the refractive index of the adsorbed layer. The sensor chip, combining two compatible technologies, can realize the simultaneous detection of biomolecules and improve the refractive index sensitivity. The structure of our chip is to prepare the ring-shaped gold electrode on the upper surface of the quartz crystal, the circular gold electrode on the bottom surface, and the spherical gold nanoparticles arrays in the center region of the ring electrode to form a QCM/LSPR dual-technology chip. Through simulation, we finally get the size of the best energy trap by the two electrodes on the upper surface and the lower surface: the ring-top electrode with a thickness of 100 nm, an inner diameter of 4 mm, and an outer diameter of 8 mm; and the bottom electrode with a thickness of 100 nm and a radius of 6 mm. By comparing the refractive index sensitivity, we chose a spherical gold nanoparticle with a radius of 30 nm and a refractive sensitivity of 61.34 nm/RIU to design the LSPR sensor chip.
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39

Yan, Yan Xia, Li Ying Jiang, Fen Fen Wang, Yan Zhang, and Jie Hu. "Electrochemical Characteristics of Aptasensor Based on MEMS Thin-Film Gold Electrode." Key Engineering Materials 562-565 (July 2013): 441–45. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.441.

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A new fabrication methods of thin-film gold electrode is reported. Electrochemical characteristics of self-assembly aptasensor based on MEMS thin-film gold electrode has been studied by lots of experiments, characteristics include immobilizing time, AC impedance, CV curves. Experiments indicate immobilizing time of DNA-SH on gold electrode is more than 15 hours. CV curves and AC impedance of MEMS thin-film gold electrode show the same conclusion that 20μm/L DNA is optimum concentration when DNA is immobilized on gold electrode. Those results present a potential universal method for other aptasensors.
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40

Lin, Hung-Yu, Chin-Cheng Liao, and Mu-Yi Hua. "Fabrication of Zinc Protoporphyrin-Modified Gold Electrode for Sensitive and Fast Detection of Vascular Endothelial Growth Factor." Chemosensors 9, no. 2 (January 23, 2021): 21. http://dx.doi.org/10.3390/chemosensors9020021.

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Vascular endothelial growth factor (VEGF) is directly related to cancer growth and its distant spread, and thus, it is considered a promising biomarker for diagnosis and post-treatment monitoring of patients with malignancies. Zinc protoporphyrin (ZnPP) is a zinc-centered raw purple compound (protoporphyrin) that has unique optical and electrochemical characteristics. In this study, we used a ZnPP-modified gold electrode to generate a chemical bond with Avastin by self-assembly and fabricate a Au/ZnPP/Avastin electrode. Bovine serum protein (BSA) was added to the electrode to prevent non-specific linkage with biomolecules. The prepared Au/ZnPP/Avastin/BSA electrodes were used for the detection of VEGF by cyclic voltammetry and amperometry. The optical properties of ZnPP were analyzed with an ultraviolet/visible/near-infrared spectrometer and a photoluminescence spectrometer. The structural and hydrophilic/hydrophobic properties of the ZnPP-modified gold electrodes were investigated by Fourier-transform infrared spectroscopy and contact angle gauge, respectively. VEGF was detected with the Au/ZnPP/Avastin/BSA electrodes prepared either with (w/LT) or without light treatment (w/o LT). The w/LT electrode showed a linear range and a sensitivity of 0.1 pg/mL–10 ng/mL and 6.52 μA/log(pg/mL)-cm2, respectively; the corresponding values for the w/o LT electrode were 10 pg/mL–10 ng/mL and 3.15 μA/log(pg/mL)-cm2, respectively. The w/LT electrode had good specificity for VEGF and was minimally influenced by other molecules. The excellent detection range, high sensitivity, and high selectivity for VEGF detection indicate that Au/ZnPP/Avastin electrodes have great potential for diagnostic and prognostic applications in patients with malignancies.
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41

Islam, Md Shafiul, Alan J. Branigan, Borkat Ullah, Christopher J. Freeman, and Maryanne M. Collinson. "The Measurement of Mixed Potentials Using Platinum Decorated Nanoporous Gold Electrodes." Journal of The Electrochemical Society 169, no. 1 (January 1, 2022): 016503. http://dx.doi.org/10.1149/1945-7111/ac41f2.

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Potentiometric redox sensing in solutions containing multiple redox molecules was evaluated using in-house constructed nanoporous gold (NPG)-platinum (Pt) and unmodified NPG electrodes. The NPG-Pt electrode was fabricated by electrodepositing Pt into the nanoporous framework of a chemically dealloyed NPG electrode. By varying the concentration of the Pt salt and the electrodeposition time, different amounts of Pt were introduced. Characterization by SEM shows the pore morphology doesn’t change with the addition of Pt and XPS indicates the electrodes contain ∼2.5–24 wt% Pt. Open-circuit potential (OCP) measurements in buffer and solutions containing ascorbic acid, cysteine, and/or uric acid show that the OCP shifts positive with the addition of Pt. These results are explained by an increase in the rate of the oxygen reduction reaction with the addition of Pt. The overall shape of the potentiometric titration curves generated from solutions containing one or more bioreagents is also highly dependent on the amount of Pt in the nanoporous electrode. Furthermore, the generation of OCP vs Log [bioreagent] from the results of the potentiometric experiments shows an ∼2-fold increase in sensitivity can result with the addition of Pt. These results indicate the promise that these electrodes have in potentiometric redox sensing.
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42

Chen, Li-Da, Wei-Jhen Wang, and Gou-Jen Wang. "Electrochemical Detection of Electrolytes Using a Solid-State Ion-Selective Electrode of Single-Piece Type Membrane." Biosensors 11, no. 4 (April 7, 2021): 109. http://dx.doi.org/10.3390/bios11040109.

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This study aimed to develop simple electrochemical electrodes for the fast detection of chloride, sodium and potassium ions in human serum. A flat thin-film gold electrode was used as the detection electrode for chloride ions; a single-piece type membrane based solid-state ion-selective electrode (ISE), which was formed by covering a flat thin-film gold electrode with a mixture of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and ion-selective membrane (ISM), was developed for sodium and potassium ions detection. Through cyclic voltammetry (CV) and square-wave voltammetry (SWV), the detection data can be obtained within two minutes. The linear detection ranges in the standard samples of chloride, sodium, and potassium ions were 25–200 mM, 50–200 mM, and 2–10 mM, with the average relative standard deviation (RSD) of 0.79%, 1.65%, and 0.47% and the average recovery rates of 101%, 100% and 96%, respectively. Interference experiments with Na+, K+, Cl−, Ca2+, and Mg2+ ions demonstrated that the proposed detection electrodes have good selectivity. Moreover, the proposed detection electrodes have characteristics such as the ability to be prepared under relatively simple process conditions, excellent detection sensitivity, and low RSD, and the detection linear range is suitable for the Cl−, Na+ and K+ concentrations in human serum.
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43

Scandurra, Antonino, Francesco Ruffino, Maria Censabella, Antonio Terrasi, and Maria Grazia Grimaldi. "Dewetted Gold Nanostructures onto Exfoliated Graphene Paper as High Efficient Glucose Sensor." Nanomaterials 9, no. 12 (December 16, 2019): 1794. http://dx.doi.org/10.3390/nano9121794.

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Non-enzymatic electrochemical glucose sensing was obtained by gold nanostructures on graphene paper, produced by laser or thermal dewetting of 1.6 and 8 nm-thick Au layers, respectively. Nanosecond laser annealing produces spherical nanoparticles (AuNPs) through the molten-phase dewetting of the gold layer and simultaneous exfoliation of the graphene paper. The resulting composite electrodes were characterized by X-ray photoelectron spectroscopy, cyclic voltammetry, scanning electron microscopy, micro Raman spectroscopy and Rutherford back-scattering spectrometry. Laser dewetted electrode presents graphene nanoplatelets covered by spherical AuNPs. The sizes of AuNPs are in the range of 10–150 nm. A chemical shift in the XPS Au4f core-level of 0.25–0.3 eV suggests the occurrence of AuNPs oxidation, which are characterized by high stability under the electrochemical test. Thermal dewetting leads to electrodes characterized by faceted not oxidized gold structures. Glucose was detected in alkali media at potential of 0.15–0.17 V vs. saturated calomel electrode (SCE), in the concentration range of 2.5μM−30 mM, exploiting the peak corresponding to the oxidation of two electrons. Sensitivity of 1240 µA mM−1 cm−2, detection limit of 2.5 μM and quantifications limit of 20 μM were obtained with 8 nm gold equivalent thickness. The analytical performances are very promising and comparable to the actual state of art concerning gold based electrodes.
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44

Nemtoi, Gh, Ig Cretescu, Iuliana Breaban, P. C. Verestiuc, and Oana-Maria Tucaliuc. "Voltammetric characterization of Hg2+ ion behaviour in acid media on different electrodes." Acta Chemica Iasi 22, no. 2 (December 1, 2014): 135–44. http://dx.doi.org/10.2478/achi-2014-0011.

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Abstract This article presents some aspects related to the cathodic discharge of the mercuric ion provided from HgCl2 into an aqueous solution of 0.1 M H2SO4 on different types of electrodes: gold disc electrode (GDE), carbon paste electrode (CPE) and platinum-disk electrode (PDE). Using the rotating disk electrode technique applied on PDE it was established that the cathodic discharge mechanism for the mercuric ion is based on both process types: mass transport, achieved by diffusion and charge transfer, achieved by electron transfer from cathode to mercury ion
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45

Cheng, Yanchao, Fangfang Sun, Jaebeom Lee, Tingchun Shi, Tianze Wang, and Yutong Li. "Gold-nanoparticles-graphene modified glassy carbon electrode for trace detection of lead ions." E3S Web of Conferences 78 (2019): 03007. http://dx.doi.org/10.1051/e3sconf/20197803007.

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In order to fulfill rapid and trace detection of heavy metals, in the study, gold-nanoparticlesgraphene modified glass carbon electrodes were used to detect lead(Pb(II)) ions. The lead ion (Pb(II)) standard sample in acetic acid-sodium acetate buffer solution was detected by the modified electrode, and the detection conditions were optimized. Under the optimized conditions, in the buffer solution with pH=4.5, the lead ions peak current showed excellent linear relationship with the lead ion concentration in the range of 0.2~50μg/L (R2=0.995), and the minimum detection limit was 0.34μg/L. At the same time, the actual water samples were determined by nano-gold-graphene/glass carbon electrodes for lead ions, and the recovery ranges was 92.94%~101.47%, which showed that the gold-nanoparticles-graphene/glass carbon electrodes possessed significant detection performance for the actual water samples.
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46

Guarín, Paula, Jonatan Cristancho, and John J. Castillo. "Rapid electrochemical detection of Staphylococcus aureus based on screen-printed gold electrodes modified with cysteine and Guinea grass (Panicum maximum) peroxidase." Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 44, no. 172 (September 29, 2020): 835–44. http://dx.doi.org/10.18257/raccefyn.1019.

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We present a novel electrochemical method for a rapid analytical detection of Staphylococcus aureus in culture and spiked milk samples through hydrogen peroxide (H2O2) consumption on a screenprinted gold electrode (SPGE) modified with cysteine and peroxidase from Guinea grass leaves (GGP). This peroxidase (POD) had a specific activity of 470 U mg-1 and it was immobilized on an SPGE surface previously modified with cysteine. Cyclic voltammograms of gold electrodes modified with peroxidase and cysteine in the presence of potassium ferrocyanide as a redox probe demonstrated an increase of approximately 5% in the current compared to the bare gold electrode. The SPGE modified electrode exhibited a good electrocatalytic response towards H2O2 reduction. We added a constant H2O2 concentration of 1x10-3 M to the culture medium and measured the decrease in the H2O2 current at -780 mV consumed by catalase from S. aureus. Our modified electrode proved to sense S. aureus in a range concentration between 3x102 and 3x108 CFU/mL-1 with a detection limit of 102 CFU/mL-1, detection time of about ~20 min, and a sensitivity of 0.020 mA CFU-1.
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47

Zhou, Cun, and Ai Chun Zhang. "DNA Electrochemical Biosensor Based on Chitosan and Core-Shell Au@SiO2 Nanoparticles." Advanced Materials Research 298 (July 2011): 135–41. http://dx.doi.org/10.4028/www.scientific.net/amr.298.135.

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In this paper, an efficient process for preparing monodisperse gold nanoparticles coated with silica shells (Au@SiO2) was reported, and a novel DNA electrochemical biosensor based on layer-by-layer self-assembled technology as well as Au@SiO2 nanoparticles was presented. Chitosan was immobilized on gold electrode by good film-forming property and lots of amino because of strong electrostatic adsorption effect between amino and gold atom, Au@SiO2 nanoparticles were also immobilized to the electrode in that it kept the excellent features of gold nanoparticles, therefore, thoil group modified DNA (SH-ssDNA) probe sequence can self-assembled on Au@SiO2 nanoparticles modified electrode with the purpose of realize quantitative detection of complementary DNA. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were applied to investigate the electrochemical behavior of different modified electrodes with methylene blue as hybrid indicator. The results in optimization experiment condition show that: the peak current difference value pre and post hybridization was linearly related to the logatithmic value of the target DNA concentration ranging from 10-10~10-6mol/L. A detection limit of 4.02×10-11mol/L can be estimated.
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48

Avdeew, Yvan, Victor Bergé-Laval, Virginie Le Rolle, Gabriel Dieuset, David Moreau, Loïg Kergoat, Benoît Martin, Christophe Bernard, Christian Gestreau, and Alfredo Hernández. "Assessment of the Use of Multi-Channel Organic Electrodes to Record ENG on Small Nerves: Application to Phrenic Nerve Burst Detection." Sensors 21, no. 16 (August 19, 2021): 5594. http://dx.doi.org/10.3390/s21165594.

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Effective closed-loop neuromodulation relies on the acquisition of appropriate physiological control variables and the delivery of an appropriate stimulation signal. In particular, electroneurogram (ENG) data acquired from a set of electrodes applied at the surface of the nerve may be used as a potential control variable in this field. Improved electrode technologies and data processing methods are clearly needed in this context. In this work, we evaluated a new electrode technology based on multichannel organic electrodes (OE) and applied a signal processing chain in order to detect respiratory-related bursts from the phrenic nerve. Phrenic ENG (pENG) were acquired from nine Long Evans rats in situ preparations. For each preparation, a 16-channel OE was applied around the phrenic nerve’s surface and a suction electrode was applied to the cut end of the same nerve. The former electrode provided input multivariate pENG signals while the latter electrode provided the gold standard for data analysis. Correlations between OE signals and that from the gold standard were estimated. Signal to noise ratio (SNR) and ROC curves were built to quantify phrenic bursts detection performance. Correlation score showed the ability of the OE to record high-quality pENG. Our methods allowed good phrenic bursts detection. However, we failed to demonstrate a spatial selectivity from the multiple pENG recorded with our OE matrix. Altogether, our results suggest that highly flexible and biocompatible multi-channel electrode may represent an interesting alternative to metallic cuff electrodes to perform nerve bursts detection and/or closed-loop neuromodulation.
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49

Zhang, Ai Chun, and Cun Zhou. "DNA Electrochemical Biosensor Based on Chitosan and Gold Nanoparticles Using Methylene Blue as Electrochemical Indicator." Advanced Materials Research 298 (July 2011): 128–34. http://dx.doi.org/10.4028/www.scientific.net/amr.298.128.

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In this paper, a novel DNA electrochemical biosensor based on layer-by-layer self-assembled technology was reported. Gold nanoparticles were firstly immobilized on chitosan modified gold electrode by large amino of chitosan because of strong electrostatic adsorption effect between amino and gold atom, and thoil group modified DNA (SH-ssDNA) probe sequence was then self-assembled onto the electrode. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were applied to investigate the electrochemical behavior of different modified electrodes with methylene blue as hybrid indicator. The results in optimization experiment condition show that: The peak current difference value pre and post hybridization was linearly related to the logatithmic value of the target DNA concentration ranging from 10-8~10-5mol/L.A detection limit of 3.55×10-9mol/L can be estimated.
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50

Zhang, Xiao Bo, Chang Bai Liu, Li Liu, Hao Shan, Lian Yuan Wang, Shou Chun Li, Xiao Chi, and Xiao Qing Bo. "Design, Simulation and Optimization of a New Micro-Structural Gas Sensor." Advanced Materials Research 677 (March 2013): 125–29. http://dx.doi.org/10.4028/www.scientific.net/amr.677.125.

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Micro-structural gas sensor with a new kind of electrode is designed. Platinum filament is selected as gold electrodes, and SiO2 is used as the thermal and electricity insulation layer. The simulation results of ANSYS reveal that when the thickness of SiO2, thickness of Si substrate, electrode with and electrode space are 50, 250, 15 and 60 µm, respectively, the sensors can own higher temperature and uniform temperature distributing in the center. The magnetic field distribution is also analyzed by ANSYS, and the results show that the new electrodes can eliminate magnetic field from the heater on the measuring signal interference, which is benefit for the improvement of sensor performance.
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