• Analytical Science and Technology
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• v.9 no.2
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• pp.161-167
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• 1996

An investigation was made of possible ways in which one could control the relative rates of cadmium deposition and hydrogen evolution by binary additive systems. Benzyl alcohol was employed as an additives due to its ability to form a hydrophobic film which inhibit the electroreduction of water to form hydrogen. The second additive was chosen to make the cadmium(II) ion less hydrophilic and increase its ability to cross the hydrophobic benzyl alcohol film and be electrodeposited at the cathode. It was shown by voltammetric and current efficiency studies that ion pairing and complexing additives could be used to accelerate the reduction of cadmium in the presence of the benzyl alcohol film. It was also shown that the benzyl alcohol film lowered the dielectric constant of the solution near the electrode enough to obtain ion pairing between the sodium ion and the negative chloride complex of cadmium and accelerate the reduction of the cadmium. This acceleration did not occur in the sulfate solution in the absence of chloride since cadmium(II) is primarily present as a positive aquo complex and ion pairing, if it occured, would not accelerate but would hinder reduction of cadmium.

• Macromolecular Research
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• v.11 no.5
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• pp.375-381
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• 2003

Silver salt complex membranes with glassy poly(methyl methacrylate) (PMMA) unexpectedly showed higher propylene permeance than those with rubbery poly(butyl methacrylate) (PBMA) where as neat PMMA is much less permeable to propylene than that of neat PBMA. Such unusual facilitated olefin transport has been systematically investigated by changing the side chain length of polymethacrylates (PMAs) from methyl, ethyl to butyl. The ab initio calculation showed almost the same electron densities of the carbonyl oxygens in the three PMAs, expecting very similar intensity of the interaction between carbonyl oxygen and silver ion. However, the interaction intensity decreases with the length of the alkyl side chain: PMMA > PEMA > PBMA according to wide angle X-ray scattering and FT-Raman spectroscopy. The difference in the interaction intensity may arise from the difference in the hydrophilicity of the three PMAs, as confirmed by the contact angle of water, which determines the concentrations of the ionic constituents of silver salts: free ion, contact ion pair and higher order ionic aggregate. However, propylene solubilities and facilitated propylene transport vary with the side chain length significantly even at the same concentration of the free ion, the most active olefin carrier, suggesting possible difference in the prohibition of the molecular access of propylene to silver ion by the side chains: the steric hindrance. Therefore, it may be concluded that both the hydrophilicity and the steric hindrance associated with the side chain length in the three PMAs are of pivotal importance in determining facilitated olefin transport through polymer/silver salt complex membranes.

• Bulletin of the Korean Chemical Society
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• v.11 no.6
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• pp.521-527
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• 1990

The binding characteristics and analytical applications of anilinium ion complexes with 18-crown-6 were studied by polarography and NMR. First, the electrochemical reduction of the 10 species of mono and dimethylsubstituted anilinium ion complexes with 18-crown-6 as host in methanol are examined. The addition of 18-crown-6 to anilinium guest solution the polarographic waves remain well defined but shifted toward more negative potentials, indicating the complex formation. The values of formation constants, log Κ for 10 species of methylsubstituted anilinium ion complexes with 18-crown-6 varies from 2.7 to 4.8 in methanol at $25^{\circ}C$. The stability order of complexes for 18-crown-6 is anilinilum > 4-methyl > 3,4-dimethyl > 3-methyl > 3,5-dimethyl > 2,4-dimethyl > 2,5-dimethyl > 2,3-dimethyl > 2-methyl > 2,6-dimethylanilinium ion. The steric hindrance shows significant effect. Second, Proton NMR was used to elucidate their interaction characteristics. From the results of so called NMR titration techniques, the behaviors of binding sites on complexation, and the stoichiometry and stability order of complex were obtained. And the later results show the satisfactory agreement with the quantitative values obtained by polarography. Finally, the individual determinations of anilinium ion mixtures were also accomplished by addition of 18-crown-6. In some mixtures of methyl or dimethylanilinium ions the reduction peaks of differential pulse method appeared into one unresolved wave attributed to the small difference of half-wave potential, ${\Delta}E_{1/2}$. In the presence of 18-crown-6, the polarographic waves were resolved into individual maxima because of the shift toward more negative direction by the difference of selectivity of anilinium ions with 18-crown-6. It may be concluded that quantitative analysis of methylanilinium ion mixture make possible because the half-wave potential shift by the selectivity difference due to the steric hindrance between methyl group and 18-crown-6 on complexation.

• Mass Spectrometry Letters
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• v.6 no.3
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• pp.59-64
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• 2015

Quadrupole ion trap mass analyzer with a simplified geometry, namely, the cylindrical ion trap (CIT), has been shown to be well-suited using in miniature mass spectrometry and even in mass spectrometer arrays. Computation of stability regions is of particular importance in designing and assembling an ion trap. However, solving CIT equations are rather more difficult and complex than QIT equations, so, analytical and matrix methods have been widely used to calculate the stability regions. In this article we present the results of numerical simulations of the physical properties and the fractional mass resolutions m/Δm of the confined ions in the first stability region was analyzed by the fifth order Runge-Kutta method (RKM5) at the optimum radius size for both ion traps. Because of similarity the both results, having determining the optimum radius, we can make much easier to design CIT. Also, the simulated results has been performed a high precision in the resolution of trapped ions at the optimum radius size.

• YAKHAK HOEJI
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• v.28 no.2
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• pp.61-67
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• 1984

A method is described for the spectrophotometric determination of platinum (IV) with 2-oximino-1-indanone based on solvent extraction of Pt:2-oximino-1-indanone complex. The 2-oximino-1-indanone reacted with Pt(IV) to form a dark-orange complex which shows a characterisic maximum absorption at 342nm. The optimum PH for the platinum extraction lies between 5.4~8.0. Beer's law obeys up to 0.98-16.3ppm of platinum (IV) and the molar absorption coefficient is $1.06{\times}10^{-4}L.mol^{-1}.cm^{-1}$. The relative standard deviation of the method was $\times2.1%$. The composition of the complex is estimated to be Pt : In= 1 : 1, by the mole ratio method and ion exchange resin experiment. The optimum condition for the determination of platinum has been studied in detail. The 2-oximin-1-indanone is found to be a selectivereagent for the determination of platinum, since the synthesixed 2-oximino-1-indanone did not react with other metals such as cobalt, cadmium, copper, manganese nickel, iron, lead and zinc, to form the complex. In this studies, we have also clarified Sindhwani and Singh's spectrophotometric determination data of various metals with acenaphthenequinone monooxime (Talanta 20,248, 1973), whose results were not correct.

• YAKHAK HOEJI
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• v.52 no.6
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• pp.426-433
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• 2008

The interaction of cadmium (II) ion with protocatechuic acid ($H_3PA$) and ethylenediaminetetraacetic acid (EDTA) were investigated in aqueous solution at different pH. The protocatechuic acid and EDTA/cadmium stochiometries for cadmium (II) binding have been determined by UV-vis spectrophotometric method. The complexation of Cd (II) ion with protocatechuic acid was formed in solution. Among the two potential sites of chelation present in the protocatechuic acid structure, the carboxylic function presents higher complexation power toward Cd (II). 1 : 1 Cd (II)-complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH when interacted with protocatechuic acid in 0.2 M $NH_3$ - 0.2 M ${NH_4}Cl$ (pH 8.0) buffer. These results suggest that Cd $({H_2}PA)^+$ complex has the optimal condition of chelation in buffer solution at 64.22 ${\mu}M$ protocatechuic acid (A=1.01455).

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.120-123
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• 1996

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.325-330
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• 1975

Complex formation between ferric ion and phosphoric acid has been studied in the wide range of the acid concentration(0${\sim}40{\%}$) by uv-visible spectroscopy and by characterization of the isolated products. The electronic spectra of Fe(III)-containing phosphoric acid solutions exhibit two visible bands at 19.2 and 24.1 kK, which are characteristic of Fe(III)-phosphate complex formation. The measurements of acid concentration dependence of the opical density of the 24.1 kK band indicates the presence of two distinct forms of Fe(Ⅲ)-phosphate complexes possibly $[Fe(H_xPO_4)]^{x+}\;and\;[Fe_2 (H_xPO_4)]^{(3+x)+}$. The 1:1 complex has been isolated for characterization, and the phosphate ion was found to be coordinated to the metal in monobasic state whereas the isolation of the dimeric species was unsuccessful.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.2
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• pp.71-78
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• 2019

Nuclear imaging is one of the most powerful measures for non-invasive diagnosis of myocardial vascular disease. Radionuclide such as ¹³N, ¹⁵O, ²⁰¹Tl and ⁸²Rb is used for the measurement of cardiac blood flow. ¹³N, ¹⁵O and ²⁰¹Tl are produced in cyclotrons while ⁸²Rb is obtained from generator. Rubidium (Rb), an alkali ion, behaves biologically like potassium, and accumulates in myocardial tissue. Rb has rapid blood clearance profile which allows the use of ⁸²Rb with a short physical half-life of 75 s for non-invasive evaluation of regional myocardial perfusion. There are several advantages of ⁸²Rb over other radioisotopes. An ultra-short half-life significantly reduces the exposure of patients to radiation and allows to repeat injections for studying the effects of medical intervention. As a positron emitter, ⁸²Rb allows positron emission tomography (PET) imaging which have shown superior diagnostic performances. ⁸²Rb can be produced from generator by decay of its parent ⁸²Sr. However, the preparation of ⁸²Sr is difficult, because appropriate purity is required to meet the specification of the product. Recently reported procedure from ARRONAX research institute showed that a Chelex-100 resin is sufficient for this purpose and additional column is not necessary. Whereas Brookhaven National Laboratory (BNL) procedure contains three ion exchange resin separation, including Chelex-100 resin. Currently, since ⁸²Sr production site is non-existent in Korea, Korea Atomic Energy Research Institute (KAERI) has plan to produce ⁸²Sr within specifications. We compared ⁸²Sr purification procedures reported from ARRONAX and BNL to investigate the most suitable procedure for our conditions.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1477-1483
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• 2004

We present the tandem mass spectrometry applications carried out to elucidate the coordination structure of Zn(II) bound lysine ternary complexes, $(Zn+Lys+Lys-H)^+$, which is a good model system to represent a simple (metallo)enzyme-substrate complex (ES). In particular, experimental efforts were focused on revealing the involvement of a lysine side chain ${\varepsilon}$-amino group in the coordination of $Zn^{2+}$ divalent ions. MS/MS fragmentation pattern showed that all the oxygen species within a complex fell off in the form of $H_2O$ in contrast to those of other ternary complexes containing amino acids with simple side chains (4-coordinate geometries, Figure 1a), suggesting that the lysine complexes have different coordination structures from the others. The participation of a lysine basic side chain in the coordination of Zn(II) was experimentally evidenced in MS/MS for $N{\varepsilon}$-Acetyl-L-Lys Zn(II) complexes with acetyl protection groups as well as in MS/MS for the ternary complexes with one $NH_3$ loss, $(Zn+Lys+Lys-NH_3-H)^+$. Detailed structures were predicted using ab initio calculations on $(Zn+Lys+Lys-H)^+$ isomers with 4-, 5-, and 6-coordinate structures. A zwitterionic 4-coordinate complex (Figure 7d) and a 5-coordinate structure with distorted bipyramidal geometry (Figure 7b) are found to be most plausible in terms of energy stability and compatibility with the experimental observations, respectively.