• 한국지하수토양환경학회지:지하수토양환경
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• 제22권1호
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• pp.1-12
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• 2017

Nitrate ($NO_3^-$), a common surface water and groundwater pollutant, poses a serious environmental problem in regions with intensive agricultural activities and dense population. It is thus important to identify the source of nitrate contamination to better manage water quality. Due to the distinct isotope compositions of nitrate among different origins, the dual isotope analysis (${\delta}^{15}N$ and ${\delta}^{18}O$) of nitrate has been widely applied to track contamination sources. This paper provided the underlying backgrounds in the isotope analysis of nitrate, which included typical ranges of ${\delta}^{15}N$ and ${\delta}^{18}O$ from various nitrate sources, isotope fractionation, the analytical methods used to concentrate nitrate from samples, and the potential limitations of the dual isotope analysis along with the resolutions. To enhance the applicability of the dual isotope analysis as well as increase the ability to interpret field data, this paper also introduced several case studies. Furthermore, other environmental tracers including ${\delta}^{11}B$ and $Cl^-/Br^-$ ratios were discussed to accompany the dual isotope analysis for better assignment of contamination sources even when microbial transformation of nitrate and/or mixing between contaminant plumes occur.

• 한국해양생명과학회지
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• 제7권2호
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• pp.61-73
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• 2022

안정동위원소 분석 기법(Stable isotope analysis, SIA)은 환경과학, 생태학, 지구생물화학, 법의학, 고고학 등 다양한 연구 분야에 활용되고 있다. 본 총설에서는 수산 및 양식 연구에 안정동위원소 비 분석 기법을 활용하기 위해 필요한 배경 지식을 소개하고자 한다. 특히, 자연값(natural abundance)을 이용하는 연구에 초점을 두었고 원소가 생물의 조직으로 통합되는 과정에서 발생하는 분별작용(동위원소 비의 변화)에 대한 원리와 안정동위원소 비가 유용한 도구로서 어떤 목적으로 생태, 환경학 분야에 이용되는지, 나아가 수산 및 양식 분야에 활용 가능한 예들을 제시하고자 한다. 본 논문을 통한 안정동위원소 분야의 이해로 향후 수산학 및 양식 연구에서 안정 동위원소 비의 다양한 활용이 기대된다.

• 자원환경지질
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• 제29권2호
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• pp.207-214
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• 1996

For many years oxygen and hydrogen isotope analysis have been used as one of the most valuable research tools to investigate many geological processes. There are many sample preparation techniques of oxygen and hydrogen isotope analysis for various geological samples. We introduce here several important sample preparation techniques for oxygen and hydrogen isotope analysis and discuss the problems of each method in detail.

• Bulletin of the Korean Chemical Society
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• 제19권6호
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• pp.634-641
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• 1998

Quasiclassical trajectory calculations were carried out for the reactions of $H+H_2$ (V=O, J=O) and its isotope variants on the Siegbahn-Liu-Truhlar-Horowitz potential energy surface for the relative energies E between 6 and 150 kcal/mol. The goal of the work was to understand the inter- and intramolecular isotope effects. We examine the relative motion of reactants during the collision using the method of analysis that monitors the intermolecular properties (internuclear distances, geometry of reactants, and final product). As in other works, we find that the heavier the incoming atom is, the greater the reaction cross section is at the same collision energy. Using the method of analysis we prove that the intermolecular isotope effect is contributed mainly by differences in reorientation due to the different reduced masses. We show that above E=30 kcal/mol recrossing also contributes to the intermolecular isotope effect. For the intramolecular isotope effect in the reactions of H+HD and T+HD, we reach the same conclusions as in the systems of $O(^3P)+HD$, F+HD, and Cl+HD. That is, the intramolecular isotope effect below E=150 kcal/mol is contributed by reorientation, recrossing, and knockout type reactions.

• 생태와환경
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• 제51권1호
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• pp.96-104
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• 2018

안정동위원소비는 전 세계적으로 수생태 환경 연구에서 매우 활발하게 적용되고 있는 분야로써, 국내에서도 2000년대 이후 담수 및 연안 생태계의 먹이망 구조 연구 등 다양한 연구에서 활용되고 있다. 최근에는 기존의 총 조직내의 안정동위원소 분석기법의 한계점을 인지하고 보완하기 위한 방안으로 아미노산의 질소 안정동위원소 분석 기법이 개발되었으며, 이를 활용한 다양한 연구 사례들이 보고됨에 따라 수생태 연구의 활용범위가 급격히 확대되고 있다. 아미노산의 질소 안정동위원소 분석기법의 기술적인 접근성의 한계에 의해 현재까지 국내에서 수생태계 연구를 위해 아미노산의 질소 안정동위원소비를 활용한 연구는 제한적인 실정이지만, 국내 다양한 하천 및 호수 그리고 연안의 환경 변화 특성을 고려할 때, 향후 수생태 환경연구에 있어 그 유용성과 활용 가치가 대단히 높을 것으로 전망된다.

• Mass Spectrometry Letters
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• 제2권4호
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• pp.80-83
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• 2011

Isotope ratio analysis of nuclear materials in individual particles is of great importance for nuclear safeguards. Although secondary ion mass spectrometry (SIMS) and thermal ionization mass spectrometry (TIMS) are utilized for the analysis of individual uranium particles, few studies were conducted for the analysis of individual uranium-plutonium mixed oxide particles. In this study, we applied SIMS and inductively coupled plasma mass spectrometry (ICP-MS) to the isotope ratio analysis of individual U-Pu mixed oxide particles. In the analysis of individual U-Pu particles prepared from mixed solution of uranium and plutonium standard reference materials, accurate $^{235}U/^{238}U$, $^{240}Pu/^{239}Pu$ and $^{242}Pu/^{239}Pu$ isotope ratios were obtained with both methods. However, accurate analysis of $^{241}Pu/^{239}Pu$ isotope ratio was impossible, due to the interference of the $^{241}Am$ peak to the $^{241}Pu$ peak. In addition, it was indicated that the interference of the $^{238}UH$ peak to the $^{239}Pu$ peak has a possibility to prevent accurate analysis of plutonium isotope ratios. These problems would be avoided by a combination of ICP-MS and chemical separation of uranium, plutonium and americium in individual U-Pu particles.

• 환경분석과 독성보건
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• 제21권4호
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• pp.237-242
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• 2018

Strontium (Sr) commonly exists in rock, groundwater, soil, plants, and animals. The Sr isotope ratio offers important information as a tracer on nature because the Sr isotopic composition is not fractionated by any biological process in these ecosystems. Hence, Sr isotope ratio has been used in several studies on tracing the Sr source for contaminated sites and human migration. In this study, we developed a separation method for Sr content, and then improved Sr isotope analysis using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). A powdered rock standard (NIST 2710a) was used to determine the removal of interference elements (Rb and Ca) and the recovery rate of Sr content. The results ranged from 98% to 106%. Additionally, three standard samples (NBS 987, IAPSO and NIST 1486) were analyzed to evaluate the precision and accuracy of the results. The measured $^{87}Sr/^{86}Sr$ ratio for all the samples were consistent with the reported values, within an error. These results indicate that our established Sr separation and Sr isotope measurement methods are reliable and can hence be useful in the fields of environmental and forensic sciences.

• 한국패류학회지
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• 제31권1호
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• pp.43-48
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• 2015

Oxygen isotope ratios (${\delta}^{18}O$) of three Pacific oyster (Crassostrea gigas) specimens from the Neolithic Yeondae-do shell midden site, Tongyeong, Korea, were analyzed to determine the seasonality of shellfish gathering and site occupation. Oxygen isotope samples were taken from the left valve hinge sections of the specimens. Oxygen isotope values ranged between -0.1 ‰ and -2.4 ‰, between -0.2 ‰ and -2.9 ‰, and between 0.3 ‰ and -2.8 ‰ in oyster specimen #one, #two and #three, respectively. The isotope profiles showed seasonal temperature cycles, providing information related to the seasonality of shellfish gathering and site occupation. Hinge-edge oxygen isotope values of the specimens showed decreasing trends after passing through maximum values (winter), indicating that they formed during spring. Thus it can be assumed that during spring season, oysters were gathered and the site was occupied.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권2호
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• pp.87-98
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• 2022

This study aims to prepare a technical protocol for identifying the source of nitrate in water using nitrogen (δ¹⁵N) and oxygen (δ¹⁸O) stable isotope ratios. The technical processes for nitrate sources identification are composed of site investigation, sample collection and analysis, isotope analysis, source identification using isotope characteristics, and source apportionment for multiple potential sources with the Bayesian isotope mixing model. Characteristics of various nitrate potential sources are reviewed, and their typical ranges of δ¹⁵N and δ¹⁸O are comparatively analyzed and summarized. This study also summarizes the current knowledge on the dual-isotope approach and how to correlate the field-relevant information such as land use and hydrochemical data to the nitrate source identification.

• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1139-1143
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• 2006

Various techniques and strategies have been developed for the identification of intracellular metabolic conditions, and among them, isotope balance-based flux analysis with gas chromatography/mass spectrometry (GC/ MS) has recently become popular. Even though isotope balance-based flux analysis allows a more accurate estimation of intracellular fluxes, its application has been restricted to relatively small metabolic systems because of the limited number of measurable metabolites. In this paper, a strategy for incorporating isotope balance-based flux data obtained for a small network into metabolic flux analysis was examined as a feasible alternative allowing more accurate quantification of intracellular flux distribution in a large metabolic system. To impose GC/MS based data into a large metabolic network and obtain optimum flux distribution profile, data reconciliation procedure was applied. As a result, metabolic flux values of 308 intracellular reactions could be estimated from 29 GC/ MS based fluxes with higher accuracy.