scholarly journals Electrochemical Impedance Spectroscopy (EIS) in Food, Water, and Drug Analyses: Recent Advances and Applications

Author(s):  
Marwa El-Azazy

Electrochemical impedance spectroscopy (EIS) is a potent electrochemical technique with a variety of applications. EIS measurements involve the application of an alternating current (AC) voltage (or current) to the system under investigation, followed by measurement of the response in the form of AC current (or voltage) as a function of frequency. By and large, EIS is an exceptionally attractive in terms of applications. Being nondestructive with a feasibility of implementation to the system to be measured and the usefulness of data obtained in characterizing the studied systems, electrochemical impedance spectroscopy has realms of applications. As food and water safety and security is becoming a universal concern, the need for a technique that can detect water and food contaminants with relatively high sensitivity and selectivity is evolving. EIS has started to realize its potential with a wide-term use in water and food analyses.

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Virgil Penta ◽  
Cristian Pirvu ◽  
Ioana Demetrescu

The main objective of the current paper is to show that electrochemical impedance spectroscopy (EIS) could be a method for evaluating and predicting of ProTaper rotary file system clinical lifespan. This particular aspect of everyday use of the endodontic files is of great importance in each dental practice and has profound clinical implications. The method used for quantification resides in the electrochemical impedance spectroscopy theory and has in its main focus the characteristics of the surface titanium oxide layer. This electrochemical technique has been adapted successfully to identify the quality of the Ni-Ti files oxide layer. The modification of this protective layer induces changes in corrosion behavior of the alloy modifying the impedance value of the file. In order to assess the method, 14 ProTaper sets utilized on different patients in a dental clinic have been submitted for testing using EIS. The information obtained in regard to the surface oxide layer has offered an indication of use and proves that the said layer evolves with each clinical application. The novelty of this research is related to an electrochemical technique successfully adapted for Ni-Ti file investigation and correlation with surface and clinical aspects.


Batteries ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 58 ◽  
Author(s):  
Daniel Manschke ◽  
Thorsten Seipp ◽  
Sascha Berthold ◽  
K. Friedrich

The state-of-the-art functionality test of classic redox-flow-stacks measures the current–voltage characteristic with the technical electrolyte. This research paper aims to simplify the validation of redox flow batteries’ functionality by conducting electrochemical impedance spectroscopy (EIS) on redox flow stacks. Since the electrolyte used in the batteries is usually toxic and aggressive, it would be a significant simplification to verify the functionality with an alternative, non-toxic fluid. EIS measurements on batteries with larger sized electrodes, multiple cells, and different fluids were performed. It was demonstrated that all impedances are repeatable, thereby validating this procedure as a qualification method for full-size and complex batteries with an alternative fluid. EIS measurements were able to detect deliberately manipulated cells. This research uses three different analysis methods for the acquired data to identify errors. The respective approaches are, firstly, (1) a comparison of the Nyquist plots; secondly, (2) a comparison of the Bode plots; and thirdly, (3) a comparison of the calculated characteristic values of the equivalent circuits. The analysis found that all methods are suitable to detect errors in the batteries. Nevertheless, the bode-plot comparison method proves to be especially advantageous, because it enables a quantitative statement.


2020 ◽  
Vol 20 (3) ◽  
pp. 517-530 ◽  
Author(s):  
Sergei V. Pereverzev ◽  
Sergiy G. Solodky ◽  
Vitalii B. Vasylyk ◽  
Mark Žic

AbstractThis paper is inspired by recently proposed approach for interpreting data of Electrochemical Impedance Spectroscopy (EIS) in terms of Distribution of Diffusion Times (DDT). Such an interpretation requires to solve a Fredholm integral equation of the first kind, which may have a non-square-integrable kernel. We consider a class of equations with above-mentioned peculiarity and propose to regularize them in weighted functional spaces. One more issue associated with DDT-problem is that EIS data are available only for a finite number of frequencies. Therefore, a regularization should unavoidably be combined with a collocation. In this paper we analyze a regularized collocation in weighted spaces and propose a scheme for its numerical implementation. The performance of the proposed scheme is illustrated by numerical experiments with synthetic data mimicking EIS measurements.


Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 899 ◽  
Author(s):  
Elisabeth Kostal ◽  
Stephan Kasemann ◽  
Can Dincer ◽  
Stefan Partel

We present recent results of the electrochemical impedance spectroscopy (EIS) measurements for interdigitated electrode arrays (IDAs) ranging from several micrometers down to hundreds of nanometers. Simulations have shown that the electric field strength between the electrodes scales with the gap size. Therefore, electrodes of varying gap sizes were fabricated and functionalized with ssDNA to empirically validate these findings. The results have shown that the impedimetric response strongly correlates with the width of the electrode fingers: the smaller the electrode gap, the larger the impedance increase.


MRS Advances ◽  
2019 ◽  
Vol 4 (44-45) ◽  
pp. 2391-2399
Author(s):  
Pablo Martínez Jiménez ◽  
Araceli Espinoza Vázquez ◽  
Francisco Javier Rodríguez Gómez

AbstractDimethylformamide (DMF) has been tested as corrosion inhibitor in a metallic material like API 5LX70 in a corrosive solution of 3% of NaCl and using electrochemical technique as electrochemical impedance spectroscopy. The results showed that 20 ppm is the best concentration to protect the metallic surface of API 5L X70 with η∼ 94%. Hydrodynamic conditions (100 and 1000 rpm) demonstrated that the DMF at different concentration afforded moderate protection against corrosion with inhibition efficiency ∼70%. Finally, the adsorption of this compound follows the Langmuir isotherm with a chemisorption-physisorption process.


Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5411 ◽  
Author(s):  
Zofia Cebula ◽  
Sabina Żołędowska ◽  
Karolina Dziąbowska ◽  
Marta Skwarecka ◽  
Natalia Malinowska ◽  
...  

The present work describes an impedimetric immunosensor for Pseudomonas syringae pv. lachrymans (Psl) detection. This pathogen infects many crop species causing considerable yield losses, thus fast and cheap detection method is in high demand. In the assay, the gold disc electrode was modified with 4-aminothiophenol (4-ATP), glutaraldehyde (GA), and anti-Psl antibodies, and free-sites were blocked with bovine serum albumin (BSA). Sensor development was characterized by cyclic voltammetry (CV) and antigen detection by electrochemical impedance spectroscopy (EIS) measurements. Seven analyzed strains of Psl were verified as positive by the reference method (PCR) and this immunoassay, proving sensor specificity. Label-free electrochemical detection was in the linear range 1 × 103–1.2 × 105 CFU/mL (colony-forming unit) with an R2 coefficient of 0.992 and a detection limit (LOD) of 337 CFU/mL. The sensor did not interfere with negative probes like buffers and other bacteria. The assay was proven to be fast (10 min detection) and easy in preparation. The advantage was the simplicity and availability of the verified analyte (whole bacteria) as the method does not require sample pretreatment (e.g., DNA isolation). EIS biosensing technique was chosen as one of the simplest and most sensitive with the least destructive influence on the probes compared to other electrochemical methods.


RSC Advances ◽  
2021 ◽  
Vol 11 (45) ◽  
pp. 27925-27936
Author(s):  
Nadia O. Laschuk ◽  
E. Bradley Easton ◽  
Olena V. Zenkina

This manuscript highlights a beginner-to-intermediate level scope of electrochemical impedance spectroscopy (EIS), which is an indispensable, non-destructive electrochemical technique that can be applied for materials characterization.


Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1506
Author(s):  
Karlheinz Kellner ◽  
Jörg Ettenauer ◽  
Martin Brandl

Scientists are always searching for inventions and developing new methods for the detection of pathogenic bacteria in drinking water. Some of those techniques are based on electrochemical reactions, performed by a device called potentiostat. For in situ analysis, there is a high demand for hardware efficient instruments with a customized set of requirements including Electrochemical Impedance Spectroscopy (EIS) measurements. Therefore, we developed the ‘EcoStat’ device. As outcome of further developments, we demonstrate the successful implementation of an EIS feature and a multiplexing unit to achieve a detection platform for multiple pathogens. We present results performed on a simplified Randles Cell model.


2019 ◽  
Author(s):  
yuan hu ◽  
Sean Brahim ◽  
Stefan Maat ◽  
Patricia Davies ◽  
Arpan Kundu ◽  
...  

This work reports a low-cost custom electrochemical instrument capable of performing rapid and accurate electrochemical impedance spectroscopy (EIS) for supercapacitors over a broad frequency band (10 mHz to 2 kHz). Conventionally, EIS is measured via sinusoidal perturbations; however, such an approach suffers from lengthy measurement time. Chirp signals have been shown previously to reduce EIS measurement time for supercapacitors for relative narrow frequency bands (1 Hz to 2 kHz). However, to characterize supercapacitors comprehensively, much broader frequency bands are required. Here, we present a custom instrument with an adaptive measurement algorithm for performing EIS measurements in a wide frequency range of 10 mHz to 2 kHz with low measurement uncertainties. The results obtained using this new technique has been validated here with a commercial instrument on several types of supercapacitors. Furthermore, measurement time on average decreases from 1500 s to less than 400 s. The overall cost of the custom instrument is 90% lower as compared to the commercial instrument. The custom instrument's accuracy, time efficiency and low cost are expected to benefit electrochemical researchers.


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