In Situ Electrochemical Impedance Spectroscopic Method for Determination of Surface Roughness and Morphological Convexity

2021 ◽  
pp. 10025-10033
Author(s):  
Rama Kant ◽  
Himanshi Goel
Keyword(s):  
Surface Roughness ◽  
Electrochemical Impedance ◽  
Spectroscopic Method ◽  
Electrochemical Impedance Spectroscopic

A Facile In-Situ Development of L-Valine Film onto the Surface of Carbon Paste Electrode Towards the Detection of Environmentally Hazardous 4-Amino Phenol

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
T. Venu Gopal ◽  
Tukiakula Madhusudana Reddy ◽  
P. Shaikshavali ◽  
G. Venkataprasad ◽  
P. Gopal
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Small Scale ◽  
Carbon Paste ◽  
Relative Standard ◽  
Paste Electrode

Abstract A small scale of environmentally hazardous 4-aminophenol can show significant impact on human health. Hence, in the present work, we have designed L-Valine film (Vf) modified carbon paste electrode (Vf/CPE) for the determination of 4-aminophenol. Herein, a facile in-situ L-Valine film was developed by electrochemical polymerization method onto the surface of bare carbon paste electrode (BCPE) with the help of cyclic voltammetry (CV) technique. A two-folds of electrochemical peak current enhancement was achieved at Vf/CPE in comparison with BCPE towards the determination of 4-aminophenol in optimum pH 7.0 of phosphate buffer solution (PBS). This was achieved due to the large surface area and conductive nature of Vf/CPE, which was concluded through the techniques of cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The effect of pH of buffer and scan rate studies were successfully studied. Morphological changes of BCPE and Vf/CPE was studied with the help of scanning electron microscopy (SEM). The formation of Vf on CPE was also analyzed by Fourier transform infrared (FTIR) spectra. Under the optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) values of 4-aminophenol were estimated with the aid of chronoamperometry (CA) technique and was found to be 9.8 μM and 32 μM, respectively. Finally the proposed method was found to have satisfactory repeatability, reproducibility and stability results with low relative standard deviation (RSD) values.

Research developments in carbon materials based sensors for determination of hormones

2021 ◽  
Author(s):  
Jamballi G. Manjunatha ◽  
Girish Tigari ◽  
Hareesha Nagarajappa ◽  
Nambudumada S. Prinith
Keyword(s):  
Carbon Materials ◽  
Electrochemical Sensors ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Supporting Electrolyte ◽  
Electroanalytical Methods ◽  
Repeatability And Reproducibility ◽  
Electrochemical Impedance Spectroscopic ◽  
Structural Aspects

Various carbon-based sensors (graphene, carbon nanotubes, graphite, pencil graphite, glassy carbon, etc.) have distinctive behavior and a broad range of importance for identifying sex hormones like estriol, estradiol, estrone, progesterone, and testosterone. The current review emphasizes voltammetric, amperometric, and electrochemical impedance spectroscopic methods for detecting some of these hormones. The existence, structural aspects, nature, and biological importance of each hormone were analyzed in detail and their analysis with different electroanalytical methods was considered. Unique methodologies and innovations of electrochemical sensors for hormones based on carbon materials modified by different agents were examined. In this review, the interaction among various sensor materials and analytes in different supporting electrolyte media is premeditated. The most important significances of the electroanalytical methodologies were discussed based on sensor selectivity, sensitivity, stability, the limit of detection, repeatability, and reproducibility.

On-Line Determination of Reaction Completion in a Closed-Loop Hydrogenator Using NIR Spectroscopy

1998 ◽  
Vol 52 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Howard W. Ward ◽  
S. Sonja Sekulic ◽  
Michael J. Wheeler ◽  
Geraldine Taber ◽  
Frank J. Urbanski ◽  
...  
Keyword(s):  
Near Infrared ◽  
Spectroscopic Method ◽  
Nir Spectroscopy ◽  
Hydrogenation Reaction ◽  
Partial Least Squares Model ◽  
Chromatographic Procedure ◽  
On Line ◽  
Palladium On Carbon

An on-line near-infrared (NIR) spectroscopic method has been developed to determine in situ the endpoint of a bulk pharmaceutical hydrogenation reaction in a loop hydrogenator. This hydrogenation employs a 5% palladium-on-carbon catalyst with tetrahydrofuran (THF) as the reaction solvent. The traditional test for monitoring the endpoint of the hydrogenation is a gas chromatographic procedure that requires an estimated 60 min from the time a sample is taken to the point where the analysis results become available. The use of NIR spectroscopy in an on-line mode of operation allows spectra to be collected every 2 min and thereby significantly improves response time and result availability. The need for obtaining results in “real time” stems from the creation of undesired side products if the reaction is allowed to continue past the optimal endpoint. If the reaction is not stopped before these side products reach a level of approximately 0.8% (wt/wt), the batch requires additional purification at considerable time and cost. A partial least-squares model was constructed, validated, and successfully used to determine the endpoint of subsequent batches.

scholarly journals Evaluations of Potable Water Tanks Epoxy Coatings Performance Using Electrochemical Impedance Spectroscopic Method

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
Haider Hadi Jasim
Keyword(s):  
Potable Water ◽  
Electrochemical Impedance ◽  
Spectroscopic Method ◽  
Corrosion Mechanism ◽  
Epoxy Coatings ◽  
High Impedance ◽  
Microscopic Inspection ◽  
Water Tanks ◽  
Electrochemical Impedance Spectroscopic

Abstract   The aim of this paper is to investigate and discuss the mechanisms of corrosion of epoxy coatings used for potable water tanks. Two distinct types of Jotun epoxy coatings: Tankguard 412 contained polyamine cured epoxy and Penguard HB contained polyamide cured epoxy, were tested and studied using the electrochemical impedance spectroscopic (EIS) method. The porosity of epoxy coatings was determined using EIS method. The obtained results showed that the two epoxy coatings have excellent behavior when applied and tested in potable water of Basrah city. Polyamine is more resistance to water corrosion compared to polyamide curing epoxy and has high impedance values. Microscopic inspection after test showed that the polyamine cured epoxy has blistering while the surface of polyamide cured epoxy showed pitting and blisters. Keywords: Corrosion mechanism , epoxy coats, porosity, potable water, , EIS method.

scholarly journals New Electrode Based on Polymer Bacteria Modified Aluminum for Degradation of Phenol

2021 ◽  
Author(s):  
Raja MAALLAH ◽  
Raja MAALLAH
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Polymer Matrix ◽  
Electrochemical Impedance ◽  
Aluminum Electrode ◽  
Simultaneous Production ◽  
Modified Aluminum Electrode

The aims of this work were to examine the new electrode, based on polymer bacteria modified aluminum electrode for simultaneous production of electricity and degradation of phenol. This electrode is based aluminum modified by bacteria inserted in the polymer matrix, developed in situ on the surface. This electrode, designated subsequently by bacteria-polymer-aluminum, Showed stable response and was characterized with voltametric methods, as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The experimental results revealed that the prepared electrode could be a feasible for degradation of hazardous phenol pollutants. The sensor was successfully applied to the determination of phenol in a real sample with satisfactory results.

Sign in / Sign up

Export Citation Format

Share Document