• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.66-74
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• 2023

In this study, a new potentiometric sensor selective to copper(II) ions was developed and characterized. The developed sensor has a polymeric membrane and contains 4.0% electroactive material (ionophore), 33.0% poly(vinyl chloride) (PVC), 63.0% bis(2-ethylhexyl)sebacate (BEHS) and 1.0% potassium tetrakis(p-chlorophenyl)borate (KTpClPB). This novel copper(II)-selective sensor exhibits a Nernstian response over a wide concentration range from 1.0×10^-6 to 1.0×10^-1 mol L^-1 with a slope of 29.6 (±1.2) mV decade^-1, and a lower detection limit of 8.75×10-7 mol L^-1. The sensor, which was produced economically by synthesizing the ionophore in the laboratory, has a good selectivity and repeatability, fast response time and stable potentiometric behaviour. The potential response of the sensor remains unaffected of pH in the range of 5.0-10.0. Based on the analytical applications of the sensor, we showed that it can be used as an indicator electrode in the quantification of Cu²⁺ ions by potentiometric titration against EDTA, and can also be successfully utilized for the determination of copper(II) ions in different real samples.

• 한국환경과학회지
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• 제21권12호
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• pp.1449-1454
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• 2012

The ion selective microelectrodes (ISME) have been applied to observe the continuous profiles of NO3-N and NH4-N in bulk solutions or biofilms. In order to evaluate the performance and applicability of ion concentration measuring system, the characteristics, such as slope of calibration curve, detection limit and potentiometric selectivity coefficient were investigated. The slopes of calibration curve showed high degree of correspondence for each target ion concentrations. And the detection limits of nitrate and ammonia ion selective microelectrode were 10-4.7 M and 10-4.4 M, respectively. These ion selective microelectrodes were proved that their own performance could be maintained for 16 days after making. NO3-N and NH4-N selective microelectrodes were also adapted to detect the continuous ion profiles of cilia media packed MLE (Modified Ludzack-Ettinger) process. And the monitored nitrate and ammonia ion profiles with the ion selective microelectrode were stable and well corresponded to the results with conventional ion chromatograph. However, the electric potential was unstable until 8 hr because of the unknown noise. The tip shape and performance of the ion selective microelectrode was stably kept over 2 days continuous monitoring.

• Bulletin of the Korean Chemical Society
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• 제23권10호
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• pp.1409-1412
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• 2002

Polymeric membrane electrodes for acetate anion based on meso-(${\alpha}$,${\alpha}$,${\alpha}$,${\alpha}$)-5,10,15,20-tetrakis[2-(penta-fluorophenylurea) phenyl]porphyrin I and similar urea-functionalized porphyrins Ⅱ-Ⅳ as neutral ionophores were prepared. The membrane based on porphyrin I exhibits the best potentiometric properties in pH 6.0 rather than pH 7.0: linear stable response over a wide concentration range (6.0 ${\times}$$10^{-5}$-1.0 ${\times}$$10^{-2}$) with a slope of -59.6 mV/decade and a detection limit of log[CH3CO$O^-$] = -5.32. Selectivity coefficients obtained from the matched potential method (MPM) in pH 6.0 indicate that interferences of hydrophobic anions are very small for the membranes of porphyrins I and II having the strong withdrawing group. The electronic effect of urea-functionalized porphyrins and pH effect of buffer solutions are discussed on the potentiometric response.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1153-1159
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• 2013

A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from $3{\times}10^{-7}$ to $1{\times}10^{-2}$ M and a lower detection limit (LDL) of $1{\times}10^{-7}$ M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.

• 통합자연과학논문집
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• 제13권2호
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• pp.41-46
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• 2020

A study is reported about the synthesis processes of various silacrown ether by the reaction of alkoxysilanes with polyethylene glycols (PEG) through transesterification. Crown ether-functionalized carbosilane dendrimers and hybrid crown ethers are also discussed. We will also address the solubility enhancement, phase-transfer catalysis of different silacrown as well as their application as Ion-selective electrodes (ISEs) and as active phase of PVC electrodes for the development of potentiometric sensors for detection of alkali-Ions.

• 센서학회지
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• 제33권2호
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• pp.63-69
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• 2024

A novel method for measuring hydrogen concentration is introduced, along with its working principle and a novel detection algorithm. This configuration requires no additional reference compartment for potentiometric electrochemical measurements; therefore, it is the most suitable for measuring dissolved hydrogen in the liquid phase. The sensor's electromotive force saturates at a certain point, depending on the hydrogen concentration during the heating process of the sensor operation. This dynamic temperature scanning method provides higher sensitivity than the constant temperature measurement method.

• Bulletin of the Korean Chemical Society
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• 제26권11호
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• pp.1738-1742
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• 2005

In this study a novel triiodide ion-selective electrode based on a charge transfer complex of iodine and Bis(2-hydroxyacetophenone)butane-2,3-dihydrazone (ICT), as a membrane carrier was prepared. The electrode has a linear dynamic range between 1.0 ${\times}$ $10^{-2}$ and 5.0 ${\times}$ $10^{-7}$ M, with a Nernstian slope of 58. 99 ${\pm}$ 0.3 mV $decade^{-1}$ and detection limit of 3.0 ${\times}$ $10 ^{-7}$ M. The potentiometric response of the proposed sensor is independent of the pH of the solution in the pH range of 3.0-10.0. The electrode possesses the advantages of short conditioning time, fast response time, and especially, very good selectivity over a large number of common organic and inorganic anions. The electrode can be used for at least 6 months without any considerable divergences in the potentials. It was used as an indicator electrode in potentiometric titration of triiodide ion with thiosulfate.

• 한국세라믹학회지
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• 제47권1호
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• pp.92-96
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• 2010

Based on the differential electrode equilibria approach, potentiometric YSZ sensors with semiconducting oxide electrodes for CO detection are developed. To improve the selectivity, sensitivity and response-time of the sensor, our strategy includes (a) selection of an oxide with a semiconducting response to CO, (b) addition of other semiconducting materials, (c) addition of a catalyst (Pd), (d) utilization of combined p- and n-type electrodes in one sensor configuration, and (e) optimization of operating temperatures. Excellent sensing performance is obtained by a novel device structure incorporating $La_2CuO_4$ electrodes on one side and $TiO_2$-based electrodes on opposite substrate faces with Pt contacts. The resulting response produces additive effects for the individual $La_2CuO_4$ and $TiO_2$-based electrodes voltages, thereby realizing an even higher CO sensitivity. The device also is highly selective to CO versus NO with minor sensitivity for NO concentration, compared to a notably large CO sensitivity.

• Preventive Nutrition and Food Science
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• 제4권1호
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• pp.79-83
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• 1999

A potentiometric biosensor employing a CO3-2 ion-selective electrode(ISE) and malic enzyme immobilization in al flow injection analysis (FIA) system was constructed. Analytical parameters were optimized for L-malate determination . The CO3-2 -ISE-FIA system was composed of a pump, an injector, a malic enzyme (EC1.1.1.40) reactor, a CO3-2 ion-selective electrode, a pH/mV meter and a recorder. Cofactor NADP was also injected with substrate for theenzyme reaction into the system. Optimized analytical parameters for L-malate determination in the CO3-2 ISE-FIA system were as follows ; flow rate, 14.5ml/hr ; sample injection volume, 100ul; enzyme loading in the reactor, 20 units ; length of the enzyme reactor , 7 cm ; tubing length form the enzyme reactor to the detector as a geometric factor in FIA, 15 cm . The response time for measuring the entire L-malate concentration range (10-2 ~10-5 mol/L ; 4 injections )was <15minutes . In this CO3-2 -ISE-FIA system, the potential differences due to th eformation of CO3-2 by the reaction of malic enzyme on L-malate were correlated to L-malate concentration in the range of 10-2 ~10-5mol/L ; the detection limit was 10-5 mol/L. This potentionmetric CO3-2 ISE--FIA system was found to be useful for L-malate measurement.

• 전기화학회지
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• 제11권1호
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• pp.59-63
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• 2008

Poly (vinylchloride) (PVC) membrane electrodes based on neutral carrier, tetracycline was prepared as an active sensor for Hg(II) ion, and tested in different contents of the potassium tetrakis (4-chlorophenyl) borate (KTpClPB) as lipophilic salt. Bis (2-ethylhexyl) sebacate (DOS), bis(l-butylpentyl) adipate (BBPA), 2-nitrophenyl octyl ether (NPOE) and dibutyl phthalate (DBP) were used as diverse plasticizing solvent mediators. This electrode shows excellent potentiometric response characteristics and display good linearity with log $[Hg^{+2}]$ versus EMF response, over a range of concentrations between $10^{-7}$ and $10^{-3}M$. With 30.8mV/decade Nernstian slope, the detection limit was $6.9{\times}10^{-9}M$ and the response time was less than 20s. The proposed electrode yields very good selectivity for mercury (II) ion over many cations such as alkali, alkaline earth, transition and heavy metal ions. And it shows a very stable potential values in a wide pH range. This reliable electrode prepared was kept at least a month without considerable alteration in their response to Hg (II) ion.