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Electrochemical System (electrochemical + system)
Selected AbstractsHigh-Temperature Electrochemistry: A ReviewELECTROANALYSIS, Issue 6 2004Gregory Abstract High-temperature electrochemistry remains a relatively unexplored field of research, although in recent years significant developments have been made. This report details the main experimental methods and approaches to heating an electrochemical system under both isothermal and non-isothermal conditions and gives an insight into the experimental and electroanalytical results obtainable under such conditions. It has been shown that the promotion of mass transport at high-temperatures, through diffusion or convection, often results in increased current signals. This increase benefits electroanalytical measurements by lowering detection limits. High temperatures also usefully enhance the sensitivity of systems with sluggish kinetics. [source] Surface-enhanced Raman spectroscopy with ultraviolet excitationJOURNAL OF RAMAN SPECTROSCOPY, Issue 6-7 2005Xu-Feng Lin Abstract Surface-enhanced Raman scattering (SERS) spectroscopy excited with a UV laser was successfully developed and the UV,SER spectra of various adsorbates, including pyridine and SCN,, on different transition metal electrodes were obtained. The experimental requirements for obtaining UV,SERS in an electrochemical system are given. The surface enhancement factor of a roughened Rh electrode covered with thiocyanate as a model molecule was estimated to be about two orders of magnitude in the UV region, consistent with our preliminary theoretical calculation based on the electromagnetic model. The investigation of SERS in the UV region will improve the understanding of the SERS enhancement mechanism and broaden the research field of SERS in areas such as surface science and the life sciences. Copyright © 2005 John Wiley & Sons, Ltd. [source] Amperometric Immunosensor for Prostate Specific Antigen Based on Co-adsorption of Labeled Antibody and Mediator in Nano-Au Modified Chitosan MembraneCHINESE JOURNAL OF CHEMISTRY, Issue 3 2008Jie-Hua LIN Abstract A quasi-reagentless amperometric immunosensor for prostate specific antigen (PSA) has been developed based on co-adsorption of horseradish peroxidase (HRP) labeled PSA antibody (anti-PSA) and tetramethyl benzidine (TMB) in nano-Au modified chitosan membrane (Au-chitosan). The immobilized TMB was used as an electron transfer mediator, which displayed a surface-controlled process at scan rates less than 45 mV/s, and a diffusion-controlled process at scan rates higher than 45 mV/s. The immunosensor with the co-immobilized anti-PSA and TMB was incubated with sample PSA antigen, and the formed immunoconjugate in the immunosensor was detected by a TMB-H2O2 -HRP electrochemical system. Under the optimal experimental conditions, PSA could be determined in the linear range from 5.0 to 30 ng·mL,1 with a detection limit of 1.0 ng·mL,1. The prepared PSA immunosensor is not only economic due to the low-cost ITO electrode obtained from industrial mass production, but also capable of batch fabrication with acceptable detection and storage stability. [source] Electrochemical Sensing of ExplosivesELECTROANALYSIS, Issue 4 2007Joseph Wang Abstract This article reviews recent advances in electrochemical sensing and detection of explosive substances. Escalating threats of terrorist activities and growing environmental concerns have generated major demands for innovative field-deployable tools for detecting explosives in a fast, sensitive, reliable and simple manner. Field detection of explosive substances requires that a powerful analytical performance be coupled to miniaturized low-cost instrumentation. Electrochemical devices offer attractive opportunities for addressing the growing explosive sensing needs. The advantages of electrochemical systems include high sensitivity and selectivity, speed, a wide linear range, compatibility with modern microfabrication techniques, minimal space and power requirements, and low-cost instrumentation. The inherent electroactivity of nitroaromatic, nitramine and nitroester compounds makes them ideal candidates for electrochemical detection. Recent activity in various laboratories has led to the development of disposable sensor strips, novel electrode materials, submersible remote sensors, and electrochemical detectors for microchip (,Lab-on-Chip') devices for on-site electrochemical detection of explosive substances. The attractive behavior of these electrochemical monitoring systems makes them very promising for addressing major security and environmental problems. [source] Regular Arrays of Microdisk Electrodes: Numerical Simulation as an Optimizing Tool to Maximize the Current Response and Minimize the Electrode Area UsedELECTROANALYSIS, Issue 23 2006Francois Abstract Microdisk electrode arrays constitute an interesting tool for electroanalysis and electrocatalysis due to their increased sensitivity and excellent limits of detection. We first demonstrate that a 2-dimensional simulation based on the diffusion domain approximation can be used to simulate the response of such electrochemical systems and therefore improve their design and fabrication process. Second, we report data showing the peak current response for arrays at three typically employed voltage scan rate as a function of the number of disks per unit area and their radii. [source] On Selection of the Perturbation Amplitude Required to Avoid Nonlinear Effects in Impedance MeasurementsISRAEL JOURNAL OF CHEMISTRY, Issue 3-4 2008Bryan Hirschorn Numerical simulations of electrochemical systems were used to explore the influence of large-amplitude potential perturbations on the measured impedance response. The amplitude of the input potential perturbation used for impedance measurements, normally fixed at a value of 10 mV for all systems, should instead be adjusted for each experimental system. Guidelines are developed for selection of appropriate perturbation amplitudes. A characteristic transition frequency is defined that can be used to tailor a frequency-dependent input signal to optimize signal-to-noise levels while maintaining a linear response. [source] | ||||||||||