• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.563-567
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• 2000

We presented the etch results of indium-tin oxide thin films by using SF$_{6}$/O$_2$gas electron cyclotron resonance plasma and conducted X-ray phtoelectron spectroscopy and quadrupole mass spectrometer analyses for the etch characteristics. The etch rate of the films was greatly dependent on that of oxygen which was the major constituent element of the films. The oxygen was removed by the forms like $O_2$or SOF$_2$. We examined the ratio of atomic content of O and In and the change of this ratio was related to the removal rate of InF$_{x}$ and the S-metal bonding.ing.

• KSBB Journal
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• v.4 no.2
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• pp.118-122
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• 1989

From the on-line mass spectrometric analyese of the exhaust gaseous composition of fermentor and the material balance equations for oxygen and carbon dioxide, oxygen uptake rate (OUR) and carbon dioxide evolution rate (CER) were calculate using a personal computer (IBM PC-AT) interfaced to a quadrupole mass spectromter. The calculate OUR and CER were used for the indirect estimation of cell and substrate concentrations during the batch culture of Candida utilis. For the estimation of sustrate concentration, the yield model of Pirt was applied. It was found that the cell and substrate (glucose) concentration could be ssatisfactorily estimataed and the results showed the more accurate estimations of both fermentation state variables when OUR data were used than CER data.

• 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.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.883-888
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• 2001

We describe an ion-surface scattering apparatus newly developed to investigate the reactive scattering process of low-energy alkali-metal ions at surfaces. The apparatus consists of an alkali-metal ion gun that is rotatable by 360°, a quadrupole mass spectrometer (QMS) with an ion energy analyzer, a sample manipulator with a heating-and-cooling stage, and an ultrahigh vacuum (UHV) chamber that houses these components. Preliminary experimental results obtained from the apparatus are presented on angular and energy distributions of the ions scattered from clean Pt(111) and water-adsorbed Pt surfaces.

• Journal of the Korean Society of Tobacco Science
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• v.30 no.2
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• pp.117-124
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• 2008

A solid phase microextraction (SPME) method in combination with gas chromatography/mass spectrometric techniques was used for the extraction and quantification of 12 selected agrochemical residues in tobacco. The parameters such as the type of SPME fiber, adsorption/desorption time and the extraction temperature affecting the precision and accuracy of the SPME method were investigated and optimized. Among three types of fibers investigated, polyacrylate (PA), polydimethylsiloxane (PDMS) and polydimethylsiloxane-divinylbenzene (PDMS-DVB), PDMS fiber was selected for the extractions of the agrochemicals. The SPME device was automated and on-line coupled to a gas chromatograph with a mass spectrometer. Mass spectrometry (MS) was used and two different instruments, a quadrupole MS and triple quadrupole MS-MS mode, were compared. The performances of the two GC-MS instruments were comparable in terms of linearity (in the range of 0.01$\sim$0.5 $\mu$g/mL) and sensitivity (limits of detection were in the low ng/mL range). The triple quadrupole MS-MS instrument gave better precision than that of quadrupole MS system, but generally the relative standard deviations for replicates were acceptable for both instruments (< 15%). The LODs was fully satisfied the requirements of the CORESTA GRL. Recoveries of 12 selected agrochemicals in tobacco yielded more than 80% and reproducibility was found to be better than 10% RSD so that SPME procedure could be applied to the quantitative analysis of agrochemical residues in tobacco.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.374-374
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• 2008

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3482-3488
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• 2014

Matrix-induced mass bias and its effect on the accuracy of isotope ratio measurements have been examined for a quadrupole-based inductively coupled plasma-mass spectrometer (Q ICP-MS). Matrix-induced mass bias effect was directly proportional to % mass difference, and its magnitude varied for element and nebulizer flow rate. For a given element and conditions in a day, the effect was consistent. The isotope ratio of Cd106/Cd114 under $200{\mu}g\;g^{-1}$ U matrix deviated from the natural value significantly by 3.5%. When Cd 111 and Cd114 were used for the quantification of Cd with isotope dilution (ID) method, the average of differences between the calculated and measured concentrations was -0.034% for samples without matrix ($0.076{\mu}g\;g^{-1}$ to $0.21{\mu}g\;g^{-1}$ for the period of 6 months). However, the error was as large as 1.5% for samples with $200{\mu}g\;g^{-1}$ U. The error in ID caused by matrix could be larger when larger mass difference isotopes are used.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.169-170
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• 2014

반도체, 디스플레이 산업 등의 진공공정이 사용되면서 공정 중에 내부기체 종류와 양을 정확한 측정하기 위해서 QMS (Quadrupole Mass Spectrometer)가 사용되고 있다. 이온전류 변화로 공정분석을 진행하므로 필라멘트로 인한 오염과 이온소스의 오염은 치명적으로 작용한다.

• Journal of Space Technology and Applications
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• v.3 no.1
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• pp.86-99
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• 2023

The mass spectrometer, being an essential scientific instrument for uncovering the origin of the solar system and life, has been used since the early 1970s on board spacecraft to obtain information of neutral and ionized elements in the atmosphere and surface of the moon, planets, asteroids, and comets. According to the 4th Basic Plan for the Promotion of Space Development (2023-2027), Korea plans to conduct lunar landing in 2032 and Mars landing in 2045 as the core goals of the plan and focuses on developing the technologies required for unmanned robotic exploration missions. In this regard, it is crucial to develop the technology of a mass spectrometer, which is the most fundamental payload for space exploration for maximized scientific achievements, however never tried before in any domestic space missions. We describe in this paper the principle of a domestically developed quadrupole mass spectrometer, its prototype model, and the test results of its performance. We conclude this paper with intended future improvements.

• Journal of Ginseng Research
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• v.43 no.4
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• pp.508-516
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• 2019

Background: Ginsenosides are not only the principal bioactive components but also the important indexes to the quality assessment of Panax ginseng Meyer. Their contents in cultivated ginseng vary with the growth environment and age. The present study aimed at evaluating the significant difference between 36 cultivated ginseng of different cultivation areas and ages based on the simultaneously determined contents of 14 ginsenosides. Methods: A high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometer (MS) method was developed and used in the multiple reaction-monitoring (MRM) mode (HPLC-MRM/MS) for the quantitative analysis of ginsenosides. Multivariate statistical analysis, such as principal component analysis and partial least squares-discriminant analysis, was applied to discriminate ginseng samples of various cultivation areas and ages and to discover the differentially accumulated ginsenoside markers. Results: The developed HPLC-MRM/MS method was validated to be precise, accurate, stable, sensitive, and repeatable for the simultaneous determination of 14 ginsenosides. It was found that the 3- and 5-yr-old ginseng samples were differentiated distinctly by all means of multivariate statistical analysis, whereas the 4-yr-old samples exhibited similarity to either 3- or 5-yr-old samples in the contents of ginsenosides. Among the 14 detected ginsenosides, Rg1, Rb1, Rb2, Rc, 20(S)-Rf, 20(S)-Rh1, and Rb3 were identified as potential markers for the differentiation of cultivation ages. In addition, the 5-yr-old samples were able to be classified in cultivation area based on the contents of ginsenosides, whereas the 3- and 4-yr-old samples showed little differences in cultivation area. Conclusion: This study demonstrated that the HPLC-MRM/MS method combined with multivariate statistical analysis provides deep insight into the accumulation characteristics of ginsenosides and could be used to differentiate ginseng that are cultivated in different areas and ages.