Virtual electrochemical analyzer

Further, this virtual electrochemical analyzer was used to measure the NO level present in the exhaled breath and also applied to measure the NO release from hydrogen peroxide (H2O2)-stimulated endothelial cells. Thus, inexpensive electronic components, small dimensions, and battery operation make this virtual electrochemical analyzer suitable for the determination of NO and ideal for in situ or field applications (Madasamy etal., 2012). 

The developed virtual electrochemical analyzer draws the CV plot and measures the concentration of biomarker present in the unknown sample. The electrochemical current responses obtained with respect to the known concentrations of biomarker can be entered simultaneously into the column given in the left side of the virtual electrochemical analyzer front panel and can plot the linear calibration curve by pressing the start button. The mathematical parameters like slope, intercept, correlation coefficient, and best linear fit values are displayed as soon as the linear graph is plotted. Further, with the help of the above parameters values, the concentration of biomarker present in the real samples can be determined and displayed immediately. 

An earher chapter discussed the electrochemical measurements with the aid of commercial and virtual electrochemical analyzers. Although the conventional electrochemical analyzers are capable of performing many different kinds of electrochemical analysis, the total cost and size of the commercial instruments limits their applicabUity in point-of-care diagnosis. Moreover, they also tend to be laboratory-based and not field portable. Therefore, the primary objective of this work is to develop a new, low-cost, hand-held electrochemical device for the measurement of the release of various biomarkers. 

Madasamy, T., Pandiar, M., Balamurugan, M., Santosh, K., Benjamin, A.R., Arunvenkatesh, K., Vairamani, K., Kotamraju, S., Karunakaran, C., 2012. Virtual electrochemical nitric oxide analyzer using copper, zinc superoxide dismutase immobilized on carbon nanotubes in polypyrrole matrix. Talanta... 

Figure 5.24 Comparison of the electrochemical response of the SODI-CNT-PPy-Pt electrode measured using virtual electrochemical NO analyzer (curves a and c) and the standard physical instrument CHI 1200B (curves b and d) in the absence (curves a and b) and presence (curves c and d) of 500 pM NO solution in 0.1 M PBS (pH 7.0) at scan rate of 100 mV s versus Ag/AgCI.

Figure 5.25(a). Further, Figure 5.25(b)—(d) show the block diagram of the virtual electrochemical NO analyzer, front panel with block diagram of the potential sweep, and front panel with block diagram of the process of the virtual electrochemical NO analyzer. The overall electroanalytical performance of the virtual electrochemical NO analyzer was compared with the standard cyclic voltammetry instrument as shown in Table 5.1. 

Table 5.1 Comparison of Electroanalytical Performance of the Virtual Electrochemical NO Analyzer Along with the Standard Cyclic Voltammetry Instrument...

Te and Cu monolayers on gold, as well as Ag and Bi monolayers on platinum were obtained by cathodic underpotential deposition and investigated in situ by the potentiodynamic electrochemical impedance spectroseopy (PDEIS). PDEIS gives the graphical representation of the real and imaginary interfacial impedance dependencies on ac frequency and electrode potential in real-time in the potential scan. The built-in analyzer of the virtual spectrometer decomposes the total electrochemical response into the responses of the constituents of the equivalent electric circuits (EEC). Dependencies of EEC parameters on potential, especially the variation of capacitance and pseudocapacitance of the double layer, appeared to be very sensitive indicators of the interfacial dynamics. 

The composition of alloys can be very conveniently and rapidly established by VIM, using the technique of differential pulse voltammetry [17]. Also, metalion-containing compounds such as sulfides can be analyzed and, in the case of mixtures, the mixing ratio can be established with high accuracy [18]. It should be kept in mind that only electrochemically active ions can be analyzed directly. However, this depends on the electrolyte used, and, by choosing an appropriate solvent, one can in principle reduce virtually any metal ion. 

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