• Mass Spectrometry Letters
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• 제4권4호
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• pp.87-90
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• 2013

Isotope amount ratios of lead in a bronze sample have been successfully determined using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Matrix separation conditions were tested and optimized using ion exchange chromatography with anion-exchange resin, AG1-X8, and sequential elution of the 0.5 M HBr and 7 M $HNO_3$ to separate lead from very high contents of copper and tin in bronze matrix. Mercury was also removed efficiently in the optimized separation condition. The instrumental isotope fractionation of lead in the MC-ICP-MS measurement was corrected by the external standard sample bracketing method using an external standard, NIST SRM 981 lead common isotope ratio standard followed by correction of procedure blank to obtain reliable isotope ratios of lead. The isotope ratios, $^{206}Pb/^{204}Pb$, $^{207}Pb/^{204}Pb$, $^{208}Pb/^{204}Pb$, and $^{208}Pb/^{206}Pb$, of lead were determined as $18.0802{\pm}0.0114$, $15.5799{\pm}0.0099$, $38.0853{\pm}0.0241$, and $2.1065{\pm}0.0004$, respectively, and the determined isotope ratios showed good agreement with the reference values of an international comparison for the same sample within the stated uncertainties

• 광물과 암석
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• 제36권4호
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• pp.355-363
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• 2023

지구물질에 존재하는 안정 동위원소의 평형상태에서의 분화(equilibrium isotope fractionation of stable isotope)는 물질의 진동 특성(vibrational properties)에 기인하며, 지구물질이 지구시스템 내에서 겪는 다양한 지질학적 과정들을 정량적으로 이해하는 데 도움을 준다. 본 연구에서는 H₂O 분자의 clumped 동위원소의 특성을 양자화학계산을 이용하여 규명하였다. 특히, 산소 동위원소(¹⁶O, ¹⁷O, ¹⁸O)와 수소 동위원소(수소, 중수소, 삼중수소)의 조합으로 구성된 H₂O 분자에 대한 산소와 수소 동위원소간의 clumping 세기를 정량적으로 계산하고, 온도 변화에 따른 clumping 세기 변화 패턴을 분석하였다. 최적화된 분자구조의 평형 결합길이(bond length)와 결합각(bond angle)은 분자의 질량수와 무관하며, 각각 0.9631-0.9633 Å과 104.59-104.62°로 일정하였다. H₂O 분자의 3개의 진동 모드의 진동수는 동위원소 질량수가 증가함에 따라 감소하였으며, 산소보다 수소 동위원소의 변화에 더 큰 영향을 받는다. 진동수를 바탕으로 계산된 동위원소 치환반응의 평형상수 또한 수소 동위원소 질량수에 따라 더 큰 변화 양상을 보인다. 무거운 동위원소 조합의 clumping 반응의 평형상수는 로그값에서 강한 선형 상관관계를 지시한다. 세 동위원소 조합의 상대적인 clumping 강도는 HD¹⁸O에 대하여 각각 1.86배(HT¹⁸O), 1.16배(HT¹⁷O), 0.703배(HD¹⁷O)로 나타났다. Clumping의 세기인 Δ₂₁ 값은 온도의 증가에 따라 감소하며 이차 상관관계를 보인다. 이는 Δ₂₁이 온도 환경 지시자로서 이용될 가능성이 있음을 지시한다. 본 계산 결과는 ¹⁷O와 삼중수소를 포함한 clumped 동위원소 분배의 경향을 최초로 정립한 연구이다. 향후, 자연계에서 산소-수소 동위원소 조성의 기원을 보다 정량적으로 이해하기 위하여 비조화적(anharmonicity) 진동이 고려된 동위원소 분배계수의 계산 또한 필요하다. 상기한 연구 결과는 H₂O 분자의 다양한 지표환경에서의 clumped 동위원소의 측정과 이를 기반으로 한 지질환경 변화 기작을 설명하는 데 사용될 것으로 기대한다.

• Mass Spectrometry Letters
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• 제2권2호
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• pp.33-36
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• 2011

The misuse of anabolic androgenic steroids is of particular concern in sports and society. Thus, it is of great importance to discriminate endogenous steroids such as testosterone or testosterone prohormones from their chemically identical synthetic copies. In this study, gas chromatography-combustion/isotope ratio mass spectrometric (GC-C/IRMS) method has been developed and validated for discriminating the origin of anabolic androgenic steroids. The method involves the solid-phase extraction, enzymatic hydrolysis with ${\beta}$-glucuronidase, HPLC-fractionation for the cleanup and analysis by GC-C/IRMS. The difference(${\Delta}^{13}C$) of urinary ${\delta}^{13}C$ values between synthetic analogues and endogenous reference compounds (ERC) by GC-C/IRMS was used to elucidate the origin of steroids, and intra- and inter-day precision, specificity and isotope fractionation were evaluated. The present GC-C/IRMS method combined with HPLC cleanup was accurate and reproducible enough to be successfully applied to the test of urine sample from suspected anabolic steroid abusers.

• Journal of Ginseng Research
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• 제41권2호
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• pp.195-200
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• 2017

Background: The natural ratios of carbon (C), nitrogen (N), and sulfur (S) stable isotopes can be varied in some specific living organisms owing to various isotopic fractionation processes in nature. Therefore, the analysis of C, N, and S stable isotope ratios in ginseng can provide a feasible method for determining ginseng authenticity depending on the cultivation land and type of fertilizer. Methods: C, N, and S stable isotope composition in 6-yr-old ginseng roots (Jagyeongjong variety) was measured by isotope ratio mass spectrometry. Results: The type of cultivation land and organic fertilizers affected the C, N, and S stable isotope ratio in ginseng (p < 0.05). The ${\delta}^{15}N_{AIR}$ and ${\delta}^{34}S_{VCDT}$ values in ginseng roots more significantly discriminated the cultivation land and type of organic fertilizers in ginseng cultivation than the ${\delta}^{13}C_{VPDB}$ value. The combination of ${\delta}^{13}C_{VPDB}$, ${\delta}^{15}N_{AIR}$, or ${\delta}^{34}S_{VCDT}$ in ginseng, except the combination ${\delta}^{13}C_{VPDB}-^{34}S_{VCDT}$, showed a better discrimination depending on soil type or fertilizer type. Conclusion: This case study provides preliminary results about the variation of C, N, and S isotope composition in ginseng according to the cultivation soil type and organic fertilizer type. Hence, our findings are potentially applicable to evaluate ginseng authenticity depending on cultivation conditions.

• ALGAE
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• 제32권4호
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• pp.349-357
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• 2017

Korean mariculture Undaria pinnatifida was collected during the months of January, February, March, and December of 2010, as well as from January of 2011 to investigate the changes in the carbon and nitrogen stable isotope ratios (${\delta}^{13}C$ and ${\delta}^{15}N$) and heavy metal with respect to it growth and to identify the factors that influence such changes. The blades of U. pinnatifida showed ${\delta}^{13}C$ and ${\delta}^{15}N$ in the range (mean) of -13.11 to -19.42‰ (-16.93‰) and 2.99 to 7.57‰ (4.71‰), respectively. Among samples with the same grow-out period, those that weighed more tended to have higher ${\delta}^{13}C$ suggesting a close association between the carbon isotope ratio and growth rate of U. pinnatifida. Indeed, we found a very high positive linear correlation between the monthly average ${\delta}^{13}C$ and the absolute growth rate in weight ($r^2=0.89$). Nitrogen isotope ratio tended to be relatively lower when nitrogen content in the blade was higher, probably due to the strengthening of isotope fractionation stemming from plenty of nitrogen in the surrounding environment. In fact, a negative linear correlation was observed with the nitrate concentration in the nearby seawaters ($r^2=0.83$). Concentrations of Cu, Cd, Pb, Cr, Hg, and Fe in the blades showed a rapid decrease in their concentration per unit weight in the more mature U. pinnatifida. Specifically, compared to adult samples, Cu, Hg, and Pb were concentrated by 30, 55, and 73 folds, respectively, in the young blades. Therefore, U. pinnatifida tissue ${\delta}^{13}C$ is as an indirect indicator of its growth rate, while ${\delta}^{15}N$ values and heavy metal concentrations serve as tracers that reflect the environmental characteristics.

• 천문학회지
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• 제40권4호
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• pp.107-111
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• 2007

The original environment of the solar system can be inferred by studying the oxygen isotope ratios in the Sun as well as in primitive meteorites and comets. The oxygen isotopic fractionation measured in primitive meteorites is mass-independent, which can be explained by the isotopic-selective photodissociation of CO. The isotopic-selective photodissociation model in a collapsing cloud by Lee et al. (2007) imply the birth of the Sun in a stellar cluster with an enhanced radiation field, which is consistent with the inferred presence of $^{60}Fe$.

• 분석과학
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• 제12권4호
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• pp.284-289
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• 1999

지하수 중에 용존된 무기탄소 화합물을 기체 방출 법을 이용하여 정량적으로 추출하였다. 기체 방출법은 직접 침전법에 비하여 소요시간이 적으며, 대기중의 이산화탄소 및 수중에 존재하는 황산이온의 영향도 무시할 수 있어 보다 효과적임을 알 수 있었다. 기체 방출법에 의한회수율 측정 결과 분당 4리터의 유량 율로 2시간 방출시켰을 때 99% 정도의 회수율을 나타내었다. 포집 시간에 따른 동위원소 분별효과를 측정하기 위하여 방출 초기 1시간과 이후 30분 간격으로 2회 포집 분석한 결과, 각각의 ${\delta}^{13}C$는 각각 -7.9‰, -3.0‰, +0.4‰로 측정되어 기체 방출법을 이용한 수중의 무기탄소 회수시 방출 초기에는 보다 가벼운 탄소의 방출이 우세하며, 보다 무거운 탄소의 방출은 후기에 이루어지는 것을 나타내었다. 그러나 이러한 동위원소 분별효과는 탄소화합물의 거의 완전한 회수에 의해 무시될 수 있었다.

• 분석과학
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• 제13권6호
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• pp.693-698
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• 2000

본 일련의 실험은 가동중인 핵시설 주위의 자연환경내 방사성탄소 농도준위 변화의 간접적인 추적을 통하여 체계적이고 장기간에 걸친 환경감시 목적으로 수행되었다. 나무 나이테 분석을 이용한 방사성탄소 농도 측정 결과는 핵시설 가동 후 농도 준위가 증가한 것을 나타내었으며, 그 변화는 발전량과 밀접한 상관관계가 있음을 알 수 있었다. 한편 섬유소 처리를 통한 안정 동위원소비, ${\delta}^{13}C$을 측정한 결과는 -30‰을 나타내었으며, 이 값은 수동법 및 능동법으로 채취한 대기 시료중의 $^{13}C$값 -17‰ 및 -8‰과는 매우 다른 결과를 나타내었다. 이런 차이는 광합성에 의한 동위원소 분별효과라고 가정할 수 있으나, 이 문제는 심도있는 연구가 필요하다.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1476-1484
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• 2023

Laboratory experiments and point monitoring of reservoir sediments have proven that stable sulfate reduction (SSR) can lower the concentrations of toxic metals and sulfate in acidic groundwater for a long time. Here, we hypothesize that SSR occurred during in situ leaching after uranium mining, which can impact the fate of acid groundwater in an entire region. To test this, we applied a sulfur isotope fractionation method to analyze the mechanism for natural attenuation of contaminated groundwater produced by acid in situ leaching of uranium (Xinjiang, China). The results showed that δ³⁴S increased over time after the cessation of uranium mining, and natural attenuation caused considerable, area-scale immobilization of sulfur corresponding to retention levels of 5.3%-48.3% while simultaneously decreasing the concentration of uranium. Isotopic evidence for SSR in the area, together with evidence for changes of pollutant concentrations, suggest that area-scale SSR is most likely also important at other acid mining sites for uranium, where retention of acid groundwater may be strengthened through natural attenuation. To recapitulate, the sulfur isotope fractionation method constitutes a relatively accurate tool for quantification of spatiotemporal trends for groundwater during migration and transformation resulting from acid in situ leaching of uranium in northern China.

• 한국물환경학회지
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• 제31권2호
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• pp.159-165
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• 2015

The organic matter sources of phytoplankton and related environmental factors influencing algal bloom in Paldang reservoir were studied using nitrogen and carbon isotope ratio(${\delta}^{15}N$, ${\delta}^{13}C$). Phytoplankton samples for stable isotope analysis were collected from four points in reservoir using a plankton net. Physicochemical water quality, algal taxa and hydrological data were collected from published monitoring material. Phytoplankton samples were analyzed by IRMS. CN ratio of each sample was very similar to that of phytoplankton from literature cited. ${\delta}^{15}N$ of each sample was decreased during July. Mixing and dilution of nitrogen sources due to increment of influx by concentrated rainfall were considered as the main reason for the decline of ${\delta}^{15}N$. Based on analyzed ${\delta}^{15}N$ value of each sample, nitrogen source of Bughan river sample was presumed to come from soil. The nitrogen sources of Namhan river and Kyeongan stream samples seemed to be sewage or animal waste. Low ${\delta}^{15}N$ value in August (2012) seemed to be influenced by isotope fractionation due to the blooming of nitrogen-fixation blue-green algae (Anabaena spp.). Variation in ${\delta}^{15}N$ values particularly by blue-green algal bloom was considered the important factor for estimating the organic matter sources of phytoplankton.