• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2722-2726
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• 2011

Plasticized poly(vinyl chloride), PVCs, with different membrane compositions tested for use in the construction of an ion-selective sensor for the determination dibucaine. A prepared membrane with dioctyl phthalate-PVC and ion-pair of N-(1-naphthyl)ethylenediamine dihydrochloride-tetraphenyl borate had a good potential to acts as a potentiometric sensor for the analysis of dibucaine. A linear relationship was obtained between potential and logC varying between $1.0{\times}10^{-6}$ and $1.0{\times}10^{-2}$ M dibucaine with a good repeatability and reproducibility. The sensor was applied for the determination of the drug in pharmaceuticals and biological fluids such as plasma and urine samples with satisfactory results. The drug electrode has also been used to study the interaction of bovine serum albumin (BSA) with dibucaine. The saturated quantities of dibucaine binding were 13.04, 5.30 and 9.70 mol/mol in 0.01, 0.02 and 0.1% of protein, respectively.

• Bulletin of the Korean Chemical Society
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• 제27권8호
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• pp.1127-1132
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• 2006

A new salicylate-selective electrode based on the complex N,N'-1,4-butylene bis(3-methyl salicylidene iminato) copper(II) as the membrane carrier was developed. The electrode exhibits a good Nernstian slope of 59.1 ${\pm}$ 1.0 mV/decade and a linear range of $1.0\;{\times}\;10^{-6}$-1.0 M for salicylate. The limit of detection was $5.0\;{\times}\;10^{-7}$ M. It has a fast response time 10 s and can be used for more than three months. The selective coefficients were determined by the fixed interference method (FIM) and could be used in the pH range 4.5-10.5. It was employed as an indicator electrode for direct determination of salicylate in pharmaceutical samples.

• 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.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.23-26
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• 2003

Titanium acetylacetonate was used in the construction of a PVC-based membrane electrode. This sensor shows very good selectivity for iodide ion over a wide variety of common inorganic and organic anions. It exhibits Nernstian behavior with a slope of 59.1 mV per decade. The working concentration ranges of the sensor are with a detection limit of $3.0\;{\times}\;10^{-6}\;M$. The response time of the sensor is very fast (<8 s), and can be used for at least twelve weeks in the pH range of 4.0-9.2. The best performance was obtained with a membrane composition of 30% PVC, 65% dibutylphthalate, 3% titanium acetylacetonate and 2% hexadecyltrimethylammonium bromide. The proposed sensor was successfully applied as an indicator electrode for titration of iodide with silver ion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1766-1768
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• 2000

신장병 진단의 척도로 요소의 농도는 매우 중요하다. 요소의 농도를 측정하기 위한 센서개발이 본 연구의 목적이다. 기존의 Potentiometry법은 Nernst식이 적용된다는 가정하에 감도를 측정했다. 실험결과 전극상에서 우레아제의 요소 가수분해 반응은 Nernst식을 적용할 수 없는 비가역적인 반응으로 판단되어 센서의 감도 측정을 Linear sweep Voltammetry(LSV)법을 이용하였다. Voltammetry법은 가역적이든 비가역적이든 관계없이 Cottrell 식에 의한 전류와 농도의 직선관계로부터 감도를 측정할 수 있다는 장점이 있다. 센서 전극의 표면은 SEM으로 분석하였고, LSV 법으로 측정한 센서의 감도는 $34{\mu}A$/decade 였다.

• Bulletin of the Korean Chemical Society
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• 제16권1호
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• pp.42-47
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• 1995

Interpolymer complex formation between basic polypeptide poly(L-proline) Form Ⅱ (PLP(Ⅱ)) and acidic polypeptides poly(L-glutamic acid) (PLGA) and poly(L-aspartic acid)(PLAA) has been studied in water-methanol (1:2 v/v) mixed-solvent by viscometry, potentiometry, light scattering and circular dichroism (CD) measurements. It has been found that polymer complexes between PLP(Ⅱ) and PLGA (or PLAA) are formed via hydrogen bonding with a stoichiometric ratio of PLP(Ⅱ)/PLGA (or PLAA)=1:2 (in unit mole ratio) and that PLP(Ⅱ) forms polymer complex more favorably with PLGA than with PLAA. In addition, the minimum (for pH 5.0) and the maximum (for pH 3.2) in reduced viscosity of dilute PLP(Ⅱ)-PLGA mixed solutions are observed at 0.67 unit mole fraction of PLGA (i.e., [PLP(Ⅱ)]/[PLGA]=1/2). These findings could be explained in terms of molecular structure (or conformation) of the complementary polymers associated with the complex formation.

• Bulletin of the Korean Chemical Society
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• 제14권5호
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• pp.594-598
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• 1993

The protonation constants of the 14-membered tetraaza macrocycles A(3,14-dimethyl-2,6,13,17-tetraazatricyclo$[l6.4.0^{1,18}.0^{7,12}]$docosane) and B(2,3,6,13,14,17-hexamethyl-2,6,13,17-tetraazatric yclo-[l6.4.$0^{1,18}.0^{7,12}$]docosane) were measured by potentiometry. The formation constants of each of these ligands with copper(II) and nickel(II) were determined by an out-of-cell spectrophotometric method. The results indicate that the per-N-methylated macrocycle B exhibits much higher selectivity for complex formation with copper(II) over nickel(II) ion than A and other related 14-membered tetraaza macrocycles. The effects of the N-and C-substituents on the basicity and the metal ion selectivity of the ligands are discussed. The synthesis and properties of copper(II) and nickel(II) complexes of B are also described.

• Nuclear Engineering and Technology
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• 제36권5호
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• pp.415-419
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• 2004

The electrode potential characteristics of a YSZ based membrane metal oxide electrode have been studied in molten LiCL at $700^{\circ}C$ by the potentiometric method. The electrode exhibited a good potential response to log[$O^2$] and data reproducibility. The calibration plot (potential vs. log[$O^2$] was found to be linear, obeying the Nernst equation. The electrode potential showed a good reversibility corresponding to increase/decrease of the oxide ion present in the molten LiCl. The physical and chemical durability appeared to be sound after several repeated uses, resulting in reproducible results. However, "the proposed electrode" failed when metallic Li was present in the melt.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.241.1-241.1
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• 2002

Tolperisone hydrochloride is used as a muscle relaxant. Very few assay methods of tolperisone were reported. such as potentiometry. spectrophotometry and high performance thin layer chromatography. In addition. there is no report related to HPLC method to determine the tolperisone level in biological sample. In this study, A very sensitive reverse phase high performance liquid chromatographic (RP-HPLC) method for the determination of tolperisone HCI in plasma has been developed. (omitted)