What is basic principle in impedance spectroscopy?
Fast-scan cyclic voltammetry for the detection of tyramine and octopamine. 2009, 394, 329-336.
Biosensors | An Open Access Journal from MDPI
Fast-scan cyclic voltammetry is an electroanalytical technique used to probe neuromodulator signaling dynamics in vivo. The popularity of fast-scan cyclic voltammetry has grown in recent years because of its ability to address various neurobiology research interests in a simple, rapid, sensitive, manner in vivo in real time. However, there still remain challenges associated with the identification and detection of neuromodulators in vivo. Here, the application of principal component regression with residual analysis to in vivo fast-scan cyclic voltammetry data is presented for the first time in a straightforward, non-mathematical context. Changing the estimation of rank from the 99.5% cumulative variance method to Malinowski's F-test better separates relevant information from noise contained in the training set cyclic voltammograms. This allows the residual analysis procedure to function more accurately in determining whether the calibration model was applicable for the unknown data set being predicted. The presence of electrode drift is shown to dramatically alter concentration prediction when it is not included during the construction of the calibration model. Several tools including a residual color plot, the pseudoinverse of the principal component regression calibration matrix, and Cook's distance are shown to successfully improve the accuracy and robustness of training set construction and concentration prediction. In addition, the sensitivity of fast-scan cyclic voltammetry is increased by increasing the scan rate of the applied voltage waveform. Analog background subtraction allows some of the charging current to be neutralized, preventing saturation of the system. The in vitro and in vivo sensitivities are significantly improved, approaching a sub-nanomolar limit of detection. Scanning to a potential of 1.3 V requires waveform modification to maintain the increased sensitivity, but the surface integrity of the carbon-fiber microelectrode is altered. Taken together, these improvements allow for a more sensitive detection scheme and a more robust and accurate quantitation methodology associated with the detection of neuromodulators in vivo with fast-scan cyclic voltammetry.
Electrochemical sensors for glucose can be divided into enzymatic and non-enzymatic. Enzymatic sensors are more specific in glucose determination. On the other hand non-enzymatic sensors are more chemically and thermally stable. Devices based on the synergistic effect of carbon nanostructures, conductive polymers and noble metal nanoparticles can be successfully used as enzymatic (using GOx) and non-enzymatic (without GOx) sensors for glucose detection. In this work, composite material containing GQDs, PPyNPs and AuNPs was synthesized and applied in both types of electrochemical sensors. Constructed systems were electrochemically characterized by voltammetric methods and their sensitivity towards glucose was examined.
Biosensors, an international, peer-reviewed Open Access journal.
Sensitive and label free detection of Prostate Specific Antigen (PSA) is still a challenge in prostate cancer diagnosis. Recently we have developed a label-free PSA aptasensor based on graphene quantum dots-gold nanorods (GQDs-AuNRs) modified screen printed electrodes. GQDs-AuNRs hybrid provides excellent platform for immobilization of PSA specific aptamers and further electrochemical sensing of PSA. For the first time multi-detection of PSA is demonstrated using three techniques simultaneously, viz. cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, sensor shows reproducible results with limit of detection (LOD) of 0.14 ngmL-1. Aptasensor is also demonstrated in real samples with satisfactory results.
D. Benne,R. Keding, Ch. Rüssel: "Redox equilibria in a tin doped melt with thebasic composition 16 Li2O, 10 CaO, 74 SiO2 studied bysquare-wave voltammetry and impedance spectroscopy"; Phys. Chem. Glasses,vol. 45, 2004, p 45-51
Professor T.J. Donohoe - Research Guides
Rüssel: "Thermodynamics of theSn2+/Sn4+ equilibrium in Li2O/Al2O3/SiO2glass melts studied by square-wave voltammetry and impedance spectroscopy";J. Non-Cryst. Solids, vol. 336, 2004, p 37-43
Measurement of Electrical Conductivity of Glass Melts
Courses | Department of Chemistry & Biochemistry | SFASU
Why to use a three electrode system in electrochemical cell instead of two electrodes?
Congratulations to Karolina - Department of Chemistry
Boron doped diamond electrode for the wastewater treatment
Research Group Web Pages
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