• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.3 s.22
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• pp.83-91
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• 2005

Pyrolysis-mass spectrometry has been used to characterize the 17 biological materials including bacteria and proteins. In this study, an in situ thermal-hydrolysis methylation(THM) procedure using tetramethylammonium hydroxide(TMAH) was employed. The biological materials are ionized using chemical ionization(CI) method with ethanol by ion trap mass spectrometer(ITMS), which attached with our own made pyrolyzer module, and then their pyrolysis mass spectra were obtained. The major distinct characteristic peaks were selected from all the range of mass spectra, and analyzed using principal component analysis(PCA) method to assess the classification/identification possibility of biological materials.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.133-147
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• 2001

Recently developing method of age determination using stepwise dissolution technique to expand the applicability of absolute age determination significantly is evaluated whether it is applicable to the Korean samples. The materials selected for the study are uranium-bearing black slates from Changni Formation of Ogcheon metamorphic belt, tourmaline separated from Naedeongni granite of Yeongnam massif, garnet and ilmenite separated from ilmenite-bearing anorthositic rock of Yeongnam massif, scheelites from Ogbang mine, and magnetite separated from Gyemyeongsan Formation of Ogcheon metamorphic belt. For the stepwise dissolution, various acid steps with different normalities and different durations were applied to leach the samples. The leachate from each step was analyzed to determine the Pb isotopic composition and concentrations of Pb and U using thermal ionization mass spectrometer. The black slates from the Changni Formation and the tourmaline from the Naedeongni granite reveal significant variation of Pb isotopic composition, which reveals the potential of such stepwise dissolution technique as a dating method. The behaviors of uranium and lead during the each stage of step leaching are different, which seem to reflect the differences in positions within the crystal lattices depending upon mineral species.

• 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.

• Conservation Science in Museum
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• v.9
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• pp.105-116
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• 2008

The Conservation Science Team of National Museum of Korea has established the data base of lead isotope ratio as the scientific research of bronze patina, which was acquired from conservtion process of metal objects, and based on this result, it intends to conduct the research related to the origin of raw material for the bronze objects. As the equipment for analysis of lead isotope ratio of the bronze patina, the thermal ionization mass spectrometer(TIMS) was used. As a part of this study, in 2nd year 2008, lead isotope ratios of total 18 samples inclding 2 samples of Round-type gold-bronze belong to Baekje period, the 2 items of head of bronze arrow belong to Nangnang(Lelang) and 10 items of the flower-shaped bronze dishes from the Unified Silla period, the 4 items of the bronze patina from the objects(era of 1 item not identified) of Wonpungtongbo(year 1078-North Sung) were analyzed.

• Analytical Science and Technology
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• v.33 no.6
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• pp.245-251
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• 2020

Lead (Pb) has been shown to be a useful tracer of contamination sources and geochemical processes such as age dating and crustal evolution. These studies require a chromatographic technique for Pb separation from geological samples. This paper presents a comparison study on the effect of eluent concentration between 6M HCl and 8M HCl on the separation of Pb from Pb resin. The results showed that the separation of Pb using 6M HCl as the eluent was not effective compared to the separation using 8M HCl. To verify this method, we measured the Pb isotopic compositions of the Pb isotopic standard (NIST NBS981) and geological reference materials (BCR-2, GSP-2, and JG-1a) using a thermal ionization mass spectrometer (TIMS). The results correspond well with the reported values within the error range, implying that this method can be useful.

• 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.

• Analytical Science and Technology
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• v.18 no.1
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• pp.27-34
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• 2005

$Li_2B_4O_7$ and $Na_2B_4O_7$ were synthesized with boron isotopic standard material for the measurement of boron isotopes of positive ions (PTIMS) such as $Li_2BO_2{^+}$ (mass 56, 57) and $Na_2BO_2{^+}$ (mass 88, 89) instead of boron mass 10 and 11. The negative ions (NTIMS) such as $^{10}BO_2{^-}$ and $^{11}BO_2{^-}$(mass 42와 43) were also measured with the same boron isotopic standard material. The precision and accuracy were compared between each method, and prescan of isobaric effect was studied. Good result was obtained from NTIMS method which provided the stable and enough peak intensities with good precision and accuracy. The measurement of boron isotopes were performed in ground water sample with about 8 ng-B ($5{\mu}L$ sample solution) obtained from IAEA for international inter-comparison analysis. The standard deviation was found to be 0.03%. Boron content of this ground water was measured using the NTIMS-IDMS. The result was $1.65{\pm}0.003ug-B/mL$ which was better precision compared to the ICP-AES result.

• Conservation Science in Museum
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• v.8
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• pp.81-95
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• 2007

The Conservation Science Team of National Museum of Korea has established the data base of lead isotope ratio as the scientific research of bronze patina, which was acquired from conservation process of metal objects, and based on this result, it intends to conduct the research related to the production places of raw material for the bronze objects. As the equipment for analysis of lead isotope ratio of the bronze patina, the thermal ionization mass spectrometer (TIMS) was used. As part of the research, in 2007, the 11 samples of the bronze Patina from the objects, believed to belong to of Nangnang(Lelang), the 6 items of bronze patina from the flower-shaped bronze dishes, belong to Unified Silla period and 4 items from the Goryeo bronze bell were acquired and analyzed the lead isotope ratio. Based on the data of the lead isotope ratio from the galena of Korea, China and Japan, the provenance raw materials were estimated through the comparison of their lead isotope ratios. In the future, the Conservation Science Team of the National Museum of Korea will collect as much bronze patina as possible from the process of conservation treatment of metal objects, and analyze them in order to conduct the study of provenance with the type, period and the region of the objects.

• Analytical Science and Technology
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• v.21 no.6
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• pp.487-494
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• 2008

An experiment was performed for zone refined Re-filament and normal (nonzone refined) Re-filament to reduce the background effect on the measurement of low level uranium samples. From both filaments, the signals which seemed to come from a cluster of light alkali elements, $(^{39}K_6)^+$, $(^{39}K_5+^{41}K)^+$ and $PbO_2$ were identified as the isobaric effect of the uranium isotopes. The isobaric effect signal was completely disappeared by heating the filament about $2000^{\circ}C$ at < $10^{-7}$ torr of vacuum for more than 1.5 hour in zone refined Refilaments, while that from the normal Re-filaments was not disappeared completely and was still remained as 3 pg. of uranium as the impurities after the degassing treatment was performed for more than 5 hours at the same condition of zone refined filaments. A threshold condition eliminating impurities were proved to be at 5 A and 30 minutes of degassing time. The uranium content as an impurity in rhenium filament was checked with a filament degassing treatment using the U-233 spike by isotope dilution mass spectrometry. A 0.31 ng of U was detected in rhenium filament without degassing, while only 3 pg of U was detected with baking treatment at a current of 5.5 A for 1 hr. Using normal Re-filaments for the ultra trace of uranium sample analysis had something problem because uranium remains to be 3 pg on the filament even though degassed for long hours. If the 1 ng uranium were measured, 0.3% error occurred basically. It was also conformed that ionization filament current was recommended not to be increased over 5.5 A to reduce the background. Finally, the contents of uranium isotopes in uranium standard materials (KRISS standard material and NIST standard materials, U-005 and U-030) were measured and compared with certified values. The differences between them showed 0.04% for U-235, 2% for U-234 and 2% for U-236, respectively.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.1
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• pp.41-47
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• 2017

After $SF_6$, which is being used in power equipment as an insulating material, is classified as one of the 6 major greenhouse gases, the maintenance and the refinement of used $SF_6$ started to get attention. In regard to this, KEPCO Research Institute (KEPRI) is developing $SF_6$ recovery and refinement technology starting with establishing a comprehensive $SF_6$ analysis system. With the analysis system, qualitative and quantitative analyses of the purity and the impurities of $SF_6$ before and after recovery, and before and after refinement have been carried out. The analysis system is comprised of GC-DID (Gas Chromatograph -Discharge Ionization Detector) for trace impurities analysis, GC-TCD (Thermal Conductivity Detector) for analyses of $SF_6$ purity and major impurities concentration from several hundred ppm up to percent range, GC-MSD (Mass Selective Detector) for analyses of impurities not included in standard gas, FT-IR (Fourier Transform-Infrared) Spectrometer for analysis of HF and $SO_2$, and moisture analyzer for analysis of moisture below 100 ppm. With this analysis system, complete analysis method of $SF_6$ has been established. This analysis system is being used in the maintenance of power equipment and the development of $SF_6$ recovery and refinement technologies. In this paper, the analysis results of four samples - gas and liquid phase $SF_6$ samples from a $SF_6$ refinement system before and after refinement are presented.