scholarly journals P(o-chlorophenol–co-o-hydroxyphenol): kinetic formation studies and pH-sensor application

2017 ◽  
pp. 11
Author(s):  
Said M. Sayyah ◽  
Sayed S. Abd-Elrehim ◽  
Rehab E. Azooz ◽  
Fatma Mohamed
Keyword(s):  
Modified Electrode ◽  
Ph Sensor ◽  
Monomer Concentration ◽  
Ph Change ◽  
Pt Electrode ◽  
Copolymer Films ◽  
Potentiometric Response ◽  
Electrochemical Copolymerization ◽  
Response Slope ◽  
Enthalpy And Entropy

<p class="PaperAbstract"><span lang="EN-US">Electrochemical copolymerization of o-chlorophenol (o-ClPh) with o-hydroxyphenol (o-HOPh) was conducted in aqueous H<sub>2</sub>SO<sub>4</sub> using cyclic voltammetry technique at the Pt electrode. The reaction rate was found to be of the second order in the monomer concentration and first order in the acid concentration. The activation energy, enthalpy, and entropy for the copolymerization were found to be 20.20 kJ mol<sup>-1</sup>, 19.24 kJ mol<sup>-1</sup> and -281.47 J K<sup>-1 </sup>mol<sup>-1</sup>, respectively. The obtained copolymer films show smooth feature with amorphous nature. Copolymer films adhere Pt electrode very well and show less reactivity in the H<sub>2</sub>SO<sub>4</sub> medium. The pH sensitivity of the poly(oClPh-co-HOPh)-modified electrode has been investigated potentiometrically using different polymer thicknesses. The potentiometric responses to pH change of the poly(oClPh-co-HOPh)-modified electrode appeared reversible and linear in the range from pH 2-11 with a maximum sub-Nernstian potentiometric response slope of 40.7 mV/pH (30 °C). The slope became close to 56.2 mV/pH in the range from pH 4 to 9 at (30 °C). The poly(oClPh-co-HOPh)-modified electrode readily responded to pH change but was not stable with time. </span></p>

scholarly journals Conductimetric Biosensor for the Detection of Uric Acid by Immobilization Uricase on Nata de Coco Membrane—Pt Electrode

2011 ◽  
Vol 6 ◽  
pp. ACI.S7346 ◽  
Author(s):  
Ani Mulyasuryani ◽  
Arie Srihardiastutie
Keyword(s):  
Uric Acid ◽  
Human Serum ◽  
Candida Utilis ◽  
Medical Laboratory ◽  
Membrane Thickness ◽  
Serum Samples ◽  
Ph Change ◽  
Pt Electrode ◽  
Enzyme Biosensor

A conductimetric enzyme biosensor for uric acid detection has been developed. The uricase, as enzyme, is isolated from Candida utilis and immobilized on a nata de coco membrane-Pt electrode. The biosensor demonstrates a linear response to urate over the concentration range 1-6 ppm and has good selectivity properties. The response is affected by the membrane thickness and pH change in the range 7.5-9.5. The response time is three minutes in aqueous solutions and in human serum samples. Application of the biosensor to the determination of uric acid in human serum gave results that compared favourably with those obtained by medical laboratory. The operational stability of the biosensor was not less than three days and the relative error is smaller than 10%.

scholarly journals A SOLID Fe2O3-GRAPHITE COMPOSITE ELECTRODE FOR pH MEASUREMENT

2015 ◽  
Vol 12 (12) ◽  
pp. 44-47
Author(s):  
Suchi Srivastava ◽  
Raja Ram Pradhananga
Keyword(s):  
Electrode Potential ◽  
Composite Electrode ◽  
Low Cost ◽  
Ph Sensor ◽  
Potential Gradient ◽  
Graphite Composite ◽  
Ph Response ◽  
Potentiometric Response ◽  
Unit Change ◽  
Oxidized Graphite

A solid Fe2O3-graphite composite electrode was prepared and investigated for use as a potentiometric pH sensor. The electrode was constructed by mixing iron (III) oxide, oxidized graphite and wax that was put over silver disc onto a polypropylene rod. The response of the electrode was investigated by measuring electrode potential as a function of pH.The effect of composition of the electrode material (Fe2O3 and oxidized graphite ration) on the electrode response was investigated. The electrode with 40% Fe2O3, 30% graphite and 30% wax by mass was found to give the best potentiometric response. This electrode behaves in Nernstian manner with a potentiometric gradient of 56.6±0.4 mV per unit change in pH at 25?C within the working range of pH 2-9.The electrode was also used for the end-point detection in potentiometric acid-base titrations and found to be an excellent electrode for pH-metric titration. The effect of oxidation of electrode on pH response was investigated by dipping electrode in 0.1N KMnO4, 1:1HNO3 and 0.1N Ce4+ solutions for different interval of time. This treatment of the electrode with oxidizing agents increased the standard electrode potential of the electrode however potential gradient per unit change in pH remains unaltered. Low cost, quick response and easy to prepare are the advantages of the iron oxide - graphite composite electrode as a pH sensor. However some metal ions and oxidising agents interfered in the determination of pH using this electrode which is the limitation of using these electrodes.Scientific World, Vol. 12, No. 12, September 2014, page 44-47

Electrode reaction induced pH change at the Pt electrode/electrolyte interface and its impact on electrode processes

2013 ◽  
Vol 688 ◽  
pp. 207-215 ◽  
Author(s):  
Ling Wen Liao ◽  
Ming Fang Li ◽  
Jing Kang ◽  
Dong Chen ◽  
Yan-Xia Chen ◽  
...  
Keyword(s):  
Electrode Reaction ◽  
Ph Change ◽  
Pt Electrode ◽  
Electrode Processes ◽  
Electrolyte Interface

scholarly journals Potentiometric Response Characteristics of Membrane-BasedCs+-Selective Electrodes Containing Ionophore-Functionalized Polymeric Microspheres

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Shane Peper ◽  
Chad Gonczy
Keyword(s):  
Ethylene Glycol ◽  
Response Characteristic ◽  
Polymeric Membrane ◽  
Ion Selective Electrodes ◽  
Polymeric Microspheres ◽  
Response Characteristics ◽  
Ph Response ◽  
Potentiometric Response ◽  
Response Slope ◽  
Ph Range

Cs+-selective solvent polymeric membrane-based ion-selective electrodes (ISEs) were developed by doping ethylene glycol-functionalized cross-linked polystyrene microspheres (P-EG) into a plasticized poly(vinyl chloride) (PVC) matrix containing sodium tetrakis-(3,5-bis(trifluoromethyl)phenyl) borate (TFPB) as the ion exchanger. A systematic study examining the effects of the membrane plasticizers bis(2-ethylhexyl) sebacate (DOS), 2-nitrophenyl octyl ether (NPOE), and 2-fluorophenyl nitrophenyl ether (FPNPE) on the potentiometric response and selectivity of the corresponding electrodes was performed. Under certain conditions, P-EG-based ion-selective electrodes (ISEs) containing TFPB and plasticized with NPOE exhibited a super-Nernstian response between1×10−3and1×10−4 M Cs+, a response characteristic not observed in analogous membranes plasticized with either DOS or FPNPE. Additionally, the performance of P-EG-based ISEs was compared to electrodes based on two mobile ionophores, a neutral lipophilic ethylene glycol derivative (ethylene glycol monooctadecyl ether (U-EG)) and a charged metallacarborane ionophore, sodium bis(dicarbollyl)cobaltate(III) (CC). In general, P-EG-based electrodes plasticized with FPNPE yielded the best performance, with a linear range from 10-1–10-5 M Cs+, a conventional lower detection limit of8.1×10−6 M Cs+, and a response slope of 57.7 mV/decade. The pH response of P-EG ISEs containing TFPB was evaluated for membranes plasticized with either NPOE or FPNPE. In both cases, the electrodes remained stable throughout the pH range 3–12, with only slight proton interference observed below pH 3.

A Fluorescence pH Sensor Based on Fluorescence Resonant Energy Transfer from Gold Nanoclusters to Porphyrin

2012 ◽  
Vol 557-559 ◽  
pp. 727-730
Author(s):  
Bo Liao ◽  
Peng Long ◽  
Hao Wen Huang ◽  
Shao Hua Shen
Keyword(s):  
Energy Transfer ◽  
Gold Nanoclusters ◽  
Ph Sensor ◽  
Ph Change ◽  
Au Nanoclusters ◽  
Simple Method ◽  
Resonant Energy ◽  
Resonant Energy Transfer ◽  
Fluorescence Modulation

The uniform Au nanoclusters ( NCs) were prepared with a simple method, and we used the uniform Au NCs and annioic tetrakis (4-sulfonatophenyl) (TPPS) porphyrin to prepare a pH sensor, of which fluorescence can be reversely modulated depending on the pH change. The fluorescence modulation of the pH sensor is related to fluorescence resonant energy transfer（FRET）from the Au NCs to TPPS.

Electrochemical Oxidation of Methanol at Pt Modified Electrode in Carbonate Solution

2013 ◽  
Vol 11 (2) ◽  
Author(s):  
M. A. Ibrahim
Keyword(s):  
Electrochemical Oxidation ◽  
Methanol Oxidation ◽  
Modified Electrode ◽  
Current Density ◽  
Carbonate Solution ◽  
Pt Electrode ◽  
Oxidation Of Methanol

In this paper, we discuss the effect of Pb, Cd, Ni, Zn, and Mn adatoms on the rate of methanol oxidation at the Pt electrode in the carbonate solution. In Na2B4O7, the presence of Cd, Ni, Mn, and Zn adatoms increased the electrocatalytic current density while the presence of Pb inhibits the methanol oxidation.

Electrochemical Copolymerization of Triphenylene and 3, 4-Ethylenedioxythiophene and Characterization of the Copolymer

2010 ◽  
Vol 150-151 ◽  
pp. 1662-1666
Author(s):  
Wu Lei ◽  
Xin Gen Xie ◽  
Feng Yun Wang ◽  
Ming Zhou Xia
Keyword(s):  
Solvent System ◽  
Redox Activity ◽  
Strong Emission ◽  
Light Emitting ◽  
Copolymer Films ◽  
Electrochemical Copolymerization ◽  
Light Emitter ◽  
Potential Applications ◽  
Ft Ir

A novel conducting copolymer, was successfully achieved by electrochemical oxidation of the monomer mixtures of 3, 4-ethylenedioxythiophene (EDOT) and triphenylene (TP) in the acetonitrile solvent system containing 0.1 mol/L LiClO4. The resulting copolymer possesses the advantages of both polytriphenylene and poly(3, 4-ethylenedioxythiophene), such as good redox activity, considerable fluorescence property and relatively high electrical conductivity. Ultraviolet-visible, FT-IR and scanning electron microscopy were used to characterize and investigate the structure of the copolymers. Fluorescence spectra revealed that the copolymer dissolved in common organic solvents was a good blue light emitter, with a strong emission at 439 nm. All these results indicate that the copolymer films as obtained have many potential applications in various fields, such as organic light-emitting diodes (OLEDs).

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