• Mass Spectrometry Letters
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• v.14 no.3
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• pp.110-115
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• 2023

The reaction of (COD)PdCl₂ with new C₃-symmetric tridentate L (COD = 1,5-cyclooctadien; L = 1,3,5-tris(picolinoyloxyethyl)cyanurate) in a mixture of acetone and dichloromethane produces single crystals consisting of unprecedented monometallacyclic [PdCl₂(L)]. This cyclic compound arises from trans-chelation of two of three donating pyridyl groups of L, while the third pyridyl group remains uncoordinated. Electrospray ionization mass spectrometry (ESI-MS) data on L exhibited the major peak corresponding to [C₂₇H₂₄N₆O₉ + H⁺]⁺. Fast atom bombardment mass spectrometry (FABMS) data on [PdCl₂(L)], however, showed the mass peak corresponding to the L instead of the present palladium(II) compound species, due to the insolubility and dissociation in solution. The physicochemical properties of the present palladium(II) compound were fully characterized by means of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, thermal analysis, single-crystal X-ray diffraction (SC-XRD) measurement.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.833-838
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• 2012

The thermal degradation products of polytrimethylene terephthalate (PTT) obtained by heating the sample in the temperature range of $250-360^{\circ}C$ under non-oxidative conditions was characterized using MALDI-TOF (matrix assisted laser desorption/ionization) mass spectrometry. The structures of the degradation products were determined and the relative compositions were estimated. The MALDI-TOF mass spectra of the thermally degraded PTT sample showed three main series of oligomer products with different end groups, which were carboxyl/carboxyl, carboxyl/allyl, and allyl/allyl. In contrast to the thermal degradation of polyethylene terephthalate (PET), the oligomers containing terephthalic anhydrides were not detected, whereas the formation of oligomers containing the unsaturated allyl ester group was confirmed by mass assignment. From these results, it was concluded that the thermal degradation of PTT proceeds exclusively through the ${\beta}$-CH hydrogen transfer mechanism, which is in accordance with the proposed reaction mechanism for the thermal degradation of polybutylene terephthalate (PBT).

• Analytical Science and Technology
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• v.23 no.5
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• pp.498-504
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• 2010

It is very difficult to get stable ion peak intensity of ruthenium by thermal ionization mass spectrometry because of its high ionization potential and high volatility of its oxides which causes to lose much of ruthenium ions, so the intensity of the signal decrease quickly. Accordingly, a study was performed in oder to increase the ionization efficiency and to prevent sample losses due to volatilization and to check with isobaric effect by impurities in filament for the measurement of ruthenium isotopes. Both single filament and double filament were tested. The former was proved to be more efficient for the stable and strong intensity of signal and revealed less isobaric effect from the molybdenum (Mo) as a filament impurity. Also, when the temperature of filament increased too high, the isobaric effect from Mo greatly appeared. That is, Mo impurity from filament gave a serious effect for measuring the ruthenium isotopes. It was proved to be of importance that filament current should be slowly increased with time interval. Finally, ruthenium isotopes were accurately measured by correction with measuring $^{94}Mo/^{99}Ru$.

• Mass Spectrometry Letters
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• v.4 no.3
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• pp.51-54
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• 2013

Isotopic analysis using thermal ionization mass spectrometry coupled with scanning electron microscopy (SEM-TIMS) was performed to determine the isotopic ratios of uranium contained in micro-particles in the 6th Nuclear Signatures Interlaboratory Measurement Evaluation Programme (NUSIMEP-6) sample. Elemental analysis by energy dispersive X-ray spectroscopy (EDS) was conducted on uranium-bearing mirco-particles, which were transferred to rhenium filaments for TIMS loading using a micromanipulation system in a SEM. A multi-ion-counter system was utilized to detect the ion signals of the four isotopes of uranium simultaneously. The isotope ratios of uranium corrected by bracketing using a reference material showed excellent agreement with the certified values. The measurement accuracy for $n(^{234}U)/n(^{238}U)$ and (b) $n(^{235}U)/n(^{238}U)$ was 10% and 1%, respectively, which met the requirements for qalification for the NetWork of Analytical Laboratories (NWAL).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.260-262
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• 2003

A thermal vapor deposition method for crystallization of insoluble analytes with matrix is established as a new sample preparation method for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). A mixture of mono, bis and tris(p-ethyl benzylidene) sorbitols was incorporated into microcrystals of ferulic acid, which was confirmed by confocal micrographs. Molecular masses of sorbitol derivatives were determined in this way by MALDI-MS without thermal decomposition.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.311-313
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• 2003

A thermal vapor deposition method for crystallization of insoluble analysis with matrix is established as a new sample preparation method for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). A mixture of mono, bis and tris(p-ethyl benzylidene) sorbitols was incorporated into microcrystals of ferulic acid, which was confirmed by confocal micrographs. Molecular masses of sorbitol derivatives were determined in this way by MALDI-MS without thermal decomposition.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.507-520
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• 2022

The Sr isotope ratio, which is used as basic data for rock formation time, crustal and mantle evolution studies, is determined by mass spectrometer such as thermal ionization mass spectrometry (TIMS) or multi-detector inductively coupled plasma mass spectrometry (MC-ICP-MS). In this technical report, we compared how incomplete chemical separation of elements affects the determination of Sr isotope ratios. For the experiment, commercial resin, NBS987(NIST SRM987) Sr isotope standard, and rock standard samples from the Geological Survey of Japan (GSJ) such as JG1a, JB3 and JA1 were used. As a result of the comparative experiment, it was clearly observed that the measured values of ⁸⁷Sr/⁸⁶Sr change when Rb remains due to incomplete separation of the NBS987 Sr isotope standard sample as well as the rock standard samples of GSJ. This indicates that complete separation is an important factor since the calculated value deviates from the true value even though correction for isotope interference by isobar is performed when measuring the isotope ratio with MC-ICP-MS. This also suggests that, when reporting the measurement result of Sr isotope ratio using MC-ICP-MS, the measurement strength of ⁸⁵Rb should be reported together with the measurement strength of all isotopes of Sr so that isotope interference by isobar can be judged.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.110-121
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• 2004

Pyrolysis-mass spectrometry, incorporating an in situ thermal hydrolysis and methylation(THM) step, has been used to study biological materials for bacteria, toxin and virus. Newly developed pyrolyzer was used to decompose biological materials, and tetramethylammonium hydroxide(TMAH) was used as a methylation reagent. Chemical ionization(CI) using ethanol and ion trap mass spectrometer(ITMS) were used to ionize and analyze of pyrolysis components, respectively. Analytical characteristics of bacteria (including spore), virus and toxin were analyzed. Also acquisition and interpretation of mass spectra as biomarkers for classification/identification of biological material s were explained.

• Mass Spectrometry Letters
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• v.1 no.1
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• pp.17-20
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• 2010

As background significantly affects measurement accuracy and a detection limit in determination of the trace amounts of uranium, it is necessary to minimize the impurities in the filaments used for thermal ionization mass spectrometry (TIMS). We have varied the degassing condition such as the heating currents and duration times to reduce the backgrounds from the filaments prepared with zone-refined rhenium tape. The most efficient degassing condition of the heating current and the duration time was determined as 3.5 A and 60 min, respectively. The TIMS measurement combined with the isotope dilution mass spectrometry (IDMS) technique showed that the uranium backgrounds were determined to be in a few fg level from blank rhenium filaments. The background minimized filaments were utilized to measure the uranium isotope ratios of a U030 (NIST) standard sample. The excellent agreement of the measurement with the certified isotope ratios showed that the degassing procedure optimized in this study efficiently reduced the impurity signals of uranium from blank rhenium filaments to a negligible level.

• Mass Spectrometry Letters
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• v.2 no.2
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• pp.57-60
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• 2011

As background significantly affects measurement accuracy and a detection limit in determination of the trace amounts of uranium, it is necessary to determine the impurities in the Lexan detector film for single particle measurements by thermal ionization mass spectrometry coupled with fission track technique (FT-TIMS). We have prepared various micro sizes of the blank Lexan detector film using a micromanipulation technique for uranium measurements by TIMS. Few tens of fg of uranium background with no remarkable dependency on the film sizes were observed in the blank Lexan films with the sizes from $50{\times}50\;{\mu}m^2$ to $300{\times}300\;{\mu}m^2$. Based on the determination of the uranium background in the Lexan film, any background correction is necessary in the isotopic analysis of a uranium single particle with micron sizes when the particle bearing Lexan film is dissected with less than $300{\times}300\;{\mu}m^2$ size. The isotopic analysis of a uranium particle in U030 standard material using TIMS was carried out to verify the applicability of the Lexan film to the single particle analysis with high accuracy and precision.