• Bulletin of the Korean Chemical Society
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• 제25권3호
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• pp.361-364
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• 2004

The potentiometric response of electrode no. 4 based on 1,3-bisbridged cofacial-calix[6]crown-5-ether (IV) gave a sub-Nernstian (45.0 mV/decade) response and the best detection limit (-log $a_{ep}$ = 4.73) towards epinephrine. The responses are decreasing in the order of epinephrine > $K^+$, dopamine > $NH_4^+$ > norepinephrine > $Na^+$. It is remarkable that the proposed electrode shows the reasonable selectivity to epinephrine against other catecholamine neurotransmitters (dopamine and norepinephrine) as well as alkali metal ions.

• Bulletin of the Korean Chemical Society
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• 제29권2호
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• pp.372-376
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• 2008

The hydrolysis of gallium(III) has been studied using potentiometric techniques under physiological conditions of temperature 37 C and ionic strength 0.15 moldm-3 NaCl and at different metal ion concentrations. Changes in pH were monitored with a glass electrode calibrated daily in hydrogen ions concentrations. The titration data within the pH range of 2.5-9.99 were analyzed to determine stability constants of hydroxide species using the SUPERQUAD program. Several different species were considered during the calculation procedure and the following hydroxides have been characterized: Ga(OH)3, Ga(OH)4- Ga3(OH)112-, Ga4(OH)11+ and Ga6(OH)153+. Speciation calculations based on the determined constants were then used to simulate the species distribution.

• Bulletin of the Korean Chemical Society
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• 제29권2호
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• pp.398-404
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• 2008

A new solvent polymeric membrane electrode, based on N,N'-bis(salicylidene)-2,2-dimethylpropane-1,3-diamine Ni(II) as the ionophore, was designed. The oxalate-selective electrode has the dynamic range between 1.0 10-6 M and 1.0 10-1 M with a Nernstian slope of -28.7 1.0 mV per decade. The detection limit was 6.3 10-7 M. The proposed electrode revealed good selectivities for oxalate over a variety of other anions and could be used in a pH range of 2.0-7.8. The electrode can be used for at least two months without any considerable divergence in potential. The designed electrode was applied as an indicator electrode in the potentiometric determination of oxalate in real samples.

• 대한화학회지
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• 제16권6호
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• pp.369-372
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• 1972

메탄올, N, N-dimethylformamide 및 acetonitrile속에서 이염기성 카르복시산 $(HOOC(CH_2)_nCOOH$, n=0∼4)의 해리상수를 유리전극을 사용하여 전위차법으로 측정했다. 두 용매간에서 각 산의 전해리상수의 차는 거의 일정한 값이 되며, 이 값은 일염기성 카르복시산의 해리상수의 차와 거의 일치했다. 그리고 $K_1/K_2$의 값은 양성자성용매인 물과 메탄올에서보다 반양성자성용매인 N,N-dimethylformamide와 acetonitrile에서 훨씬 더 크다.

• 대한화학회지
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• 제20권2호
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• pp.129-135
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• 1976

4-전극 측정 용기와 정전위 전자회로를 써서 직독식 전기전도도 측정장치를 고안하여 KCl, HCl등 전해질 용액의 전기전도도를 측정하였다. 이 장치는 상용되고 있는 브릿지회로와 2-전극 용기를 쓰는 방법에서 당면하는 어려운 문제들, 특히 전극에서의 전기 이중층의 존재와 파라디임피던스 등으로 나타나는 전기화학적으로 복잡한 성질들로 인한 문제들을 피하여 정밀하고 간편한 측정에 쓰이도록 만들었다.

• 약학회지
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• 제47권6호
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• pp.356-360
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• 2003

Nitroso-2-naphthol-3,6-disulfonic acid, disodium salt (NRS) was used as an organic ligand to prepare basic drug-selective polymeric membrane electrode. The sensing membrane of the electrode consited of basic drug-meta1(II)-NRS as an ion-exchanger site in a poly(vinyl chloride) matrix plasticized with 2-nitrophenyl octyl ether (NPOE). The metal ions used were Fe$^{2+}$, Co$^{2+}$, Ni$^{2+}$ and Cu$^{2+}$. The electrodes exhibited fast and wide linear response in the basic drug concentration of 10$^{-5}$ ∼10$^{-3}$ mol/l with a response slope of 50∼60 mV/decade in a buffer solution of pH 4∼8. The electrodes exhibited good selectivity for many basic compounds.mpounds.

• Preventive Nutrition and Food Science
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• 제3권1호
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• pp.36-42
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• 1998

Ion-selective eleltrodes(ISEs) are simple electrodechemical devices for the direct measurement of ions in the samples. A novel potentiometric biosensor for the determination of L-Malate or D-isocitrate has been developed by using CO2-3 -ISE-FIA system was composed of a pump, an injector, a malic enzyme or isocitric dehydrogenase enzyme reactor, a CO2-3 -ISE, a pH/mV meter, and an integrater. The various factors, such as buffer capacity types of plstericizer and polymer, were optimized for the CO2-3 selectivity. In this novel CO2-3 --ISE-FIA system, the potential difference due to the amount of CO2-3 produced from each enzyme reaction was proportional to the amount of L-malate or D-isocitrate.

• 한국세라믹학회지
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• 제30권11호
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• pp.933-940
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• 1993

SO42-/Al2O3 powder was prepared by the coprecipitation method from the Al(NO3)3.9H2O and NH4OH and followed by being treated with various concentrations of sulfuric acid. The characterization of these powders was performed with XRD, BET and FT-IR. The surface charge density at alumina/KCl(aq) interface was measured by potentiometric titration method. From the experimental data it was shown that acid strength, specfic surface area, and structure of surface treated alumina were independent on the amount of exchanged SO42-. However, the acid amounts of alumina were increased with the amounts of SO42- formed on alumina surface. The relation between the acid amount of SO42- ion exchanged alumina surface and the surface charge density for SO42-/Al2O3/KCl(aq) interface was investigated.

• 한국의류학회지
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• 제27권5호
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• pp.523-523
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• 2003

The change of interactions of anionic surfactants, sodium dodecyl sulfate(SDS) and sodium tetradecyl sulfate(575) in the presence of electrolytes, to the chitosan-based polyelectrolyte(sol＇n and gel phase) were studied. The chitosan gel used in this study were crosslinked with epichlorohydrin(ECH). Binding isotherms were determined by potentiometric technique using a surfactant ion selective solid-state electrode and the results were represented by using the sequence generating function(SGF) method. The results of binding isotherm were shown comparatively high cooperativity. The addition of electrolytes in the chitosan/SDS system resulted in a shift of the binding to higher free surfactant concentration because of screen effect by the electrolytes. Degree of binding of chitosan gel was higher than that of chitosan sol＇n. And also a conformational phase transition of the chitosan gel in the presence of electrolytes has been investigated.

• 한국의류학회지
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• 제27권5호
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• pp.524-532
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• 2003

The change of interactions of anionic surfactants, sodium dodecyl sulfate(SDS) and sodium tetradecyl sulfate(575) in the presence of electrolytes, to the chitosan-based polyelectrolyte(sol＇n and gel phase) were studied. The chitosan gel used in this study were crosslinked with epichlorohydrin(ECH). Binding isotherms were determined by potentiometric technique using a surfactant ion selective solid-state electrode and the results were represented by using the sequence generating function(SGF) method. The results of binding isotherm were shown comparatively high cooperativity. The addition of electrolytes in the chitosan/SDS system resulted in a shift of the binding to higher free surfactant concentration because of screen effect by the electrolytes. Degree of binding of chitosan gel was higher than that of chitosan sol＇n. And also a conformational phase transition of the chitosan gel in the presence of electrolytes has been investigated.