• Nuclear Engineering and Technology
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• v.32 no.3
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• pp.205-213
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• 2000

A series of laboratory experiments was conducted to investigate the fixation characteristics of poly(vinylalcohol)-poly(methacrylic acid)(PVA-PMAA) mixed solution on the soluble ${\gamma}$- radionuclides. Using the potentiometric titration technique, it was found out that the PVA and PMAA in a solution form intermacromolecular complex. The mobilized portion of each radionuclide by water from sand surface treated with a fixative was measured by ${\gamma}$-ray spectroscopy. The mobilized portion of minor radionuclides such as 241Am, 154Eu, 155Eu and 144Ce were higher than those of 134Cs and 137Cs. The capability of PVA-PMAA system was better among the candidate solutions for the fixation of total ${\gamma}$-radioactivity. 134,137Cs which is composed of more than 85 % of total ${\gamma}$-radioactivity could be fixed effectively by the PVA-PMAA solution.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.253-262
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• 1981

The AgI/ PV${\cdot}$THF membrane electrode could be used as an indicator electrode in the potentiometric titration of single halide and mixture halide solutions with the standard solution of silver nitrate. The errors in the stepwise titrations of mixture halide solutions were considerably large, but by addition of flocculating agent, such as $NaNO_3$ or $Ba(NO_3)_2$, in the sample solution, the errors were greatly reduced. Also, the effects of gelatin, filter paper and temperature on the titration errors were examined.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.421-425
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• 2003

A new thallium(Ⅰ) selective electrode based on dibenzylidaza-18-crown-6 as mambrane carrier was successfully prpared. The electrode exhibitis a near-Nernstian response for $ T1^+$ ions over a wide concentration range from $1.0×10^{15}-1.0×10^{-1}$M at 25℃, and was found to be selective, precise and useable within the pH range 4.0-11.0. The electrode was successfully used as an indicator electrode in potentiometric titration of thallium ions.

• Journal of the Korean Chemical Society
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• v.29 no.2
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• pp.137-143
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• 1985

Construction of a liquid membrane type of cupric ion selective electrode and its application to the potentiometric titration have been studied. A liquid ion-exchange membrance was prepared by extracting Cu(II) in aqueous solution into 1-(2-pyridylazo)-2-naphthol/nitrobenzene. A Ag/AgCl internal reference electrode was dipped into the aqueous reference solution of $1.00 {\times} 10^{-3}M\;Cu(NO_3)_2$ buffered with HAc-NaAc buffer solution, which was in contact with the nitrobenzene extract. The electrode showed the nernstian response to Cu(II) in the concentration range from $1.00{\times} 10^{-6}$ to $1.00{\times} 10^{-3}$M. The most suitable ion-exchanger concentration in the liquid membrane was $1.00{\times} 10^{-4}$M. The selectivity coefficients of the electrode for the various metal cations were investigated. The electrode was applied to the potentiometric titration of Cu(II) with EDTA.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.969-973
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• 1999

In this work, we studied the degree of hydrolysis of ion exchanger in $NH_4OH$ solution and sorption characteristics of $NH_3$ by potentiometric titration curves with using carboxylic acid ion exchanger Fiban K-4. We knew that the theoretical pH values agreed with the experimental pH values on the $NH_4OH$ concentrations in various concentrations of supporting electrolyte $(NH_4)_2SO_4$. The sorption values of $NH_3$ using the ion exchanger can be calculated from equivalent sorption curves for various pH. Also, the degree of hydrolysis increased with decreasing concentration of supporting electrolyte and pH. In order to obtain the mono ion form below 0.01 M as the decreasing concentration of supporting electrolyte, the pH values should be increased. From these results, therefore, the concentrations of supporting electrolyte and pH values were determined.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.450-454
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• 2023

Chloride ions in the alloy powder used as flux in Flux Cored Arc Welding (FCAW) can cause pores on the bead surface of the welding metal to cause defects, or chloride remaining in the alloy powder can cause corrosion of the metal. Combustion-ion chromatography is mainly used to quantify the chloride ions in alloy powder, but there is a limitation in that the equipment is expensive and requires a high degree of expertise. Therefore, this study aims to find an easy and accurate quantification method in the field by comparing combustion-ion chromatography (C-IC), which is mainly used for chloride ion quantification of alloy powder, X-ray fluorescence analysis (XRF), and potentiometric titration. In this article, magnesium-aluminum alloy powder is applied to the quantification of chloride ions because it is most commonly used as flux. This study confirmed that potentiometric titration can be applied to the quantification of chloride ions in the alloy powder in the industry field.

• Journal of the Korean Chemical Society
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• v.22 no.3
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• pp.128-132
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• 1978

The potentiometric end-point of redox titrations determined by nulling the second derivative of the titration curve by numerical differentiation method is analyzed by using an electronic digital computer. The error involved in the method is shown to be dependent on the location of the equivalence point in the titrant addition increment that encompasses the latter. The error increases as the equivalence point moves away from the mid-point of the increment toward a maximum value that is as great as a half of the increment. Therefore, when the numerical differentiation method is used to null the second derivative, the end-point should be compared with the steepest point of the titration curve or diluted titrant should be used in the vicinity of the end-point.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.3
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• pp.160-171
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• 1993

Surface charge characteristics of Ultisol(Luisiana soil from Philippines), Alfisol(Maahas soil from Philippines), and Inceptisol(Yongii soil from Korea) were studied by way of potentiometric titration, backtitration technique, and ion adsorption method(or CEC - AEC method). The PZNC(point of zero net charge) values determined by ion adsorption method were much lower than the natural pHs in all soils, indicating that all soil samples bore net negative surface charge. The PZSE (point of zero salt effect) values determined by potentiometric titration and backtitration technique were identical in Luisiana and Yongii soils but not in Maaghas soil. All soils showed higher PZSE values than PZNC values probably due to the influence of permanent negative charge. The permanent charge calculated by the theory of Uehara and Gillman (1980) occupied quite low portion of the CEC measured at pH 7 in all soils. Backtitration technique corrected errors of potentiometric titration at extreme pH. However, it still overestimate the surface charge compared with ion adsorption method. Therefore, the ion adsorption method was recommanded for the surface charge measurement of the usual soils which have high negative charge components.

• Journal of the Korean Chemical Society
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• v.14 no.4
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• pp.287-296
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• 1970

The varation of potential and completeness of reaction in an oxidation-reduction titration of Red$_1$ ($a\;Ox_1+N_1e{\leftrightarrow}b\;Red_1)\;by\;Ox_2\;(C\;Ox_2+n_2e{\leftrightarrow}d\;Red_2)$ is analyzed on the basis of general expressions. It is shown that the reaction deficiency as well as the rate of variation of the potential with titration fraction change in proportion to the $[n_2(a-b)-n_1(c-d)]$ th power of the concentration of the reagents. In particular, at the equivalence point, the expression of the potential contains a concentration dependent term that is proportional to ac-bd. Thus, the equivalence-point potential varies with the concentration of the reagents unless ac=bd is satisfied. It is also shown that the sharpness of the potentiometric titration curve is shown to occur either prior to or after the equivalence point depending upon whether $n_1cn_2b$, the deviation being the same order of magnitude as the relative deficiency at the equivalence point.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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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.