• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.279-288
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• 2013

In this study, we analyzed the values of ionization and ionization constants in the chemistry textbooks developed during 1945-2009 year. The chemistry teachers compared strength of strong acids in aqueous solution by questionnaire. In the questionnaire, we searched chemistry teachers' cognitions about the discordance reason of ionization constant formulation and the values in the textbooks. The subjects were 46 chemistry teachers. As results, the teachers compared the strength of strong acids in aqueous solution based on the ionization and ionization constant values in the textbooks. They didn't notice the problem of discordance of ionization constant formulation and the values in the textbooks. Even though they recognized the problem, they could not find the solution, and thought the problem arrived by experiment error or measurement error.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1590-1594
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• 2002

Liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) has been used for the determination of sulfonamides in meat. Five typical sulfonamides were selected as target compounds, and beef meat was selected as a matrix sample. As internal standards, sulfapyridine and isotope labeled sulfamethazine (${13}^C_6$-SMZ) were used. Compared to the results of recent reports, our result have shown improved precision to a RSD of 1.8% for the determination of sulfamethazine spiked with 75 ng/g level in meat.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.832-839
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• 1992

Lead has been determined by Resonance Ionization Mass Spectrometry (RIMS) through one-color-two-photon ionization, two-color-two-photon ionization and three-color-three-photon ionization in a vacuum chamber equipped with Time-of-Flight(TOF) mass spectrometer. In all cases, the first excited state chosen was 6p7s($^3P_1$) state and the transition was at 283.3 nm in wavelength from the ground state. By using various concentrations of lead standard solutions, the calibration curve is obtained in the range of 0.1 ${\mu}g$ to 1.0 pg in both ionization schemes. The detection limit was estimated as 20 pg for the two-color ionization, while 10 pg for the three-color ionization experiment.

• Journal of Astronomy and Space Sciences
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• v.35 no.1
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• pp.1-6
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• 2018

The reanalysis of the previously published abundance pattern of mild barium star HD202109 (${\zeta}$ Cyg) and the chemical compositions of 129 thin disk barium stars facilitated the search for possible correlations of different stellar parameters with second ionization potentials of chemical elements. Results show that three valuable correlations exist in the atmospheres of barium stars. The first is the relationship between relative abundances and second ionization potentials. The second is the age dependence of mean correlation coefficients of relative abundances vs. second ionization potentials, and the third one is the changes in correlation coefficients of relative abundances vs. second ionization potentials as a function of stellar spatial velocities and overabundances of s-process elements. These findings demonstrate the possibility of hydrogen and helium accretion from the interstellar medium on the atmospheres of barium stars.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.101-105
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• 2004

The laser ablation/ionization time-of-flight mass spectrometry is applied to the isotopic analysis of solid samples using a home-made instrument. The technique is convenient for solid sample analysis due to the onestep process of vaporization and ionization of the samples. The analyzed samples were lead, cadmium, molybdenum, and ytterbium. To optimize the analytical conditions of the technique, several parameters, such as laser energy, laser wavelength, size of the laser beam on the samples surface, and high voltages applied on the ion source electrodes were varied. Low energy of laser light was necessary to obtain the optimal mass resolution of spectra. The 532 nm light generated mass spectra with the higher signal-to-noise ratio compared with the 355 nm light. The best mass resolution obtained in the present study is ~1,500 for the ytterbium.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2383-2385
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• 2010

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.1055-1058
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• 2011

• Mass Spectrometry Letters
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• v.8 no.1
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• pp.1-7
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• 2017

Studies performed on heterogeneous reactions of hydroxyl radicals (OH) in aerosol materials of tropospheric interest are presented, focusing on the chemical ionization mass spectrometric approach. Kinetic investigations of these reactions reduced deviation in the estimation of OH concentration in the troposphere by atmospheric modeling from field measurements. Recently, OH uptake was investigated under wet conditions to acquire kinetic information under more realistic conditions representative of the troposphere. The information on the mechanism and kinetics of OH uptake by tropospheric aerosol materials will contribute to the updating of atmospheric models, allowing a better understanding of the troposphere.

• Bulletin of the Korean Chemical Society
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• v.27 no.6
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• pp.947-950
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• 2006

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1437-1439
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• 2007