• The Journal of the Petrological Society of Korea
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• v.13 no.4
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• pp.238-243
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• 2004

Duwon meteorite was fallen on 23 November 1943 in Duwonmyeon, Goheung, Jeolanam-Do. We measured rare earth element abundance of Duwon meteorite by isotope dilution thermal ion mass spectrometry (ID-TIMS) and ICP-MS. As a result, except La and Ce, abundance of other rare earth element show a correspondence within 10％ of error range. However, La and Ce show more than 70％ in abundance, which is considered due to 1) experimental procedure or 2) inhomogeneity of sample. Leedey meteorite was fallen on 25 November 1943 in Dewey County, Oklahoma, USA. which suggested that fallen difference between Leedey and Duwon meteorites is only 2 days. Leedey and Duwon meteorites are classified as ordinary chondrite of L6 type. In Leedey chondrite-normalized REE pattern, Duwon meteorite shows nearly flattened, which suggests close relationship between Leedey and Duwon meteorites meteoritically or cosmochemically.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.1-10
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• 2013

This study was performed to summarize application of ${\delta}^{13}C$, ${\delta}^{37}Cl$ and ${\delta}D$ of trichloroethylene (TCE) to studies on environmental forensic field regarding identification of TCE sources and evaluation of contribution of TCE to groundwater using data collected from literatures. ${\delta}^{13}C$, ${\delta}^{37}Cl$ and ${\delta}D$ of TCE give some information regarding sources of TCE because they show specific value according to manufacturing method. Also, TCE do not show a significant isotopic fractionation owing to adsorption and dilution. The isotopic fractionation mainly occurs by biodegradation. In addition, isotopic fractionation factor for TCE is different according to a kind of microorganism participated in biodegradation. However, the isotopic data of TCE have to be applied with chemical compositions of TCE and other hydrogeologic factors because isotopic fractionation of TCE is influenced by various factors.

• Analytical Science and Technology
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• v.23 no.6
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• pp.524-530
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• 2010

Chloramphenicol is one of the most effective antibiotics for treatment of food-producing animals for typhoid fever. However, it has been reported that it caused severe side effects such as aplastic anemia in human, therefore the use of chloramphenicol for food-producing animal is prohibited by European Union and other countries. In this study, the analytical method using isotope dilution liquid chromatography-mass spectrometry (ID-LC/MS) was established for accurate determination of chloramphenicol in meat. Chloramphenicol was extracted with ethylacetate from porcine and solid phase extraction cartridge was used for enhancing the recovery. The residue of chloramphenicol in porcine was analyzed using the liquid chromatography mass spectrometer (LC/MS) interfaced with electrospray ionization source. Analysis was performed in negative mode with selected reaction mornitoring mode at m/z 321${\rightarrow}$257 of $[M-H]^-$ ${\rightarrow}$ $[M-H-(HCOCl)]^-$ and m/z 326 ${\rightarrow}$ 262 channels for its isotope. The established method was tested using fortified samples at the level of 0.2 1, 10, $25\;{\mu}g$/kg and analytical results agreed with the gravimetrically fortified values within their uncertainties. This method was validated by analyzing a certified reference material, BCR 445, from IRMM (Institute for Reference Materials and Measurement). Our measurement values agreed with the certified value within their uncertainties. The uncertainty of our measured value was much lower than that the certified value from IRMM.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.10
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• pp.1517-1524
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• 2007

The [$^2H_5$]phenylalanine model was compared with the [1-$^{13}C$]leucine method to determine whole body protein synthesis (WBPS) and degradation (WBPD) in sheep fed at two levels. The animals were fed either 103 (M-diet) or 151 (H-diet) kcal $ME/kg^{0.75}/day$ once daily in a crossover design for 21 days each. The isotope dilutions were simultaneously conducted as a primed-continuous infusion of [$^2H_5$]phenylalanine, [$^2H_2$]tyrosine and [1-$^{13}C$]leucine on each dietary treatment. The WBPS and WBPD calculated from the [$^2H_5$]phenylalanine model were lower (p = 0.009 and p = 0.003, respectively) than those calculated from the [1-$^{13}C$]leucine method. The WBPS tended to be higher (p = 0.08) and WBPD was numerically higher (p = 0.33) for H-diet than M-diet in the [$^2H_5$]phenylalanine model, whereas the WBPS was numerically higher (p = 0.37) for H-diet and WBPS remained similar (p = 0.79) between diets in the [1-$^{13}C$]leucine method. However, the absolute values and the directions of WBPS as well as WBPD from M-diet to H-diet were comparable between the [$^2H_5$]phenylalanine model and [1-$^{13}C$]leucine method. Moreover, the values vary depending on the use of the respective amino acid contents in the carcass protein when calculating WBPS and WBPD. Therefore, it is concluded that the [$^2H_5$]phenylalanine model could be used as an alternative to the [1-$^{13}C$]leucine method for the determination of WBPS and WBPD in sheep.

• The Korean Journal of Zoology
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• v.3 no.1
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• pp.24-30
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• 1960

본실험의 목적은 탄산기에 방사성동위원소 C14를 표식한 sodium acetate ($CH_3$C14 OONA)를 사용하여 염소의 위내에 존재하는 acetate 의 위벽으로부터의 흡수율과 위의 acetate의 평균함량을 측정하는데 있다. C14 로 표식된 sodium acetate(specific activity 1.35$\times$108 cpm./g.)를 급사 3 시간후의 염소의 위내에 주입하고 주입 2분후부터 약 2분간격으로 위 내용물을 추울하여 column chromatograpy를 이용하여 acetate를 분리정량한 후 그의 specific activity를 측정하였다. 주입후 3 분경까지는 위내에 존재하는 acetate에 의한 표식 acetate의 희석으로 말미암아 specific activity 는 급격히 감소되어 갔고 3 분후부터는 감소도가 비교적 완만하였으나 역시 계속적으로 감소되어갔다. 희석완료후의 이 specific activity 감소는 위벽을 통한 acetate를 흡수와 위 내용물로부터의 acetate 생성으로 인한 것으로서, 이 감소율로부터 acetate의 위벽흡수속도를 추정할 수 있다. 상기 specific activity의 감소 graph 로부터 추정된 위내 acetate의 량은 본실험의 제조건하에서 약 30 g이었으며 위내 acetate 의 specific activity가 1/2 로 감소되는데 요하는 평균 시간은 약 4 분이었다. 이는 위내에 존재하는 acetate량의 약 절반은 4 분동안에 위벽을 통과함을 의미한다.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.5
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• pp.495-502
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• 1996

Much recent research on protein and amino acid (AA) digestive physiology of pigs has been concerned with measurement of the ileal apparent and true digestion and absorption. For measurement of the ileal apparent digestibility of AA, the steered ileo-caecal valve cannulation (SICV) and the ileo-rectal anastomosis (IRA) techniques appear to be the more reliable and simple methods, when compared with any methods requiring use of a marker for calculation of digestibility, or with the complex techniques of ileo-caecal re-entrant cannula (ICRC) and the postvalve ileo-colic re-entrant cannula (IPVC). On the other hand, the peptide alimentation ultrafiltration methods might be a better choice for measurement of the ileal endogenous nitrogen (N) and AA flow in a routine feedstuff analysis, although the classical method of $^{15}N-isotope$ dilution method is still a standard method for N and AA nutrition research in pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.75-79
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• 1992

Fourteen Sahiwal ${\times}$ Friesian crossbred heifers were used in a 10-wk feeding trial to determine maintenance energy requirements and efficiency of gain. The heifers were individually fed with a diet consisting of 30% dry grass and 70% concentrates at either 110, 140 or 180% of the anticipated maintenance requirement ($494kJ\;ME/kg^{0.75}/day$). Liveweight of individual heifers was measured weekly to calculate diet requirements and average daily gain (ADG). Diet digestibility was determined for all heifers to determine ME intake. Retained energy (RE) of individual heifers was determined from changes in total body fat and protein using a TOH isotope dilution procedure and, assuming calorific values of 39.3 and 23.6 kJ/g for fat and protein respectively. The estimated ME for maintenance was 433 and $470kJ/kg^{0.75}/day$ by liveweight (ADG) equilibrium and energy (RE) equilibrium analysis respectively. ME requirement for one g of liveight gain was 28 kJ.

• Analytical Science and Technology
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• v.18 no.6
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• pp.520-528
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• 2005

Two biological Certified Reference Materials (CRMs), KRISS 108-04-001 (oyster tissue) and 108-05-001 (water dropwort stem), were prepared by Korea Research Institute of Standards and Science (KRISS)during FY '01. The certified values of these materials had been determined by Isotope Dilution Mass Spectrometry (IDMS) for six elements (Cd, Cr, Cu, Fe, Pb and Zn). Additional analytical works are now progressing to certify the concentrations of a number of the environmental and nutrimental elements in these CRMs. The certified values in a CRM are usually determined by using a single primary method with confirmation by other method(s) or using two independent critically-evaluated methods. Instrumental Neutron Activation Analysis (INAA) plays an important role in the determination of certified values as it can eliminate the possibility of common error sources resulting from sample dissolution. In this study INAA procedure was used in determination of 23 elements in these two biological CRMs to acquire the concentration information and the results were compared with KRISS certified values.

• Journal of the korean society of oceanography
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• v.31 no.2
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• pp.97-106
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• 1996

Advantages and disadvantages of four radioisotopic methods, $^{3}H$-thymidine, $^{3}H$-adenine, $^{3}H$-leucine, and $^{35}S$-sulfate, for measuring bacterial production were reviewed. The maior issues discussed in production methods were: (1) whether all the actively growing bacteria take up the radiolabeled (organic) tracers; (2) how each target molecule should be purified (nonspecific labeling); and (3) how important the determination of the precursor pool specific activity is (internal isotope dilution). Since all the radioisotoic methods have their own advantages and disadvantages, careful consideration must be paid in choosing the radioisotope according to the conditions of each environment investigated.

• Mass Spectrometry Letters
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• v.11 no.4
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• pp.108-112
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• 2020

A certified reference material (CRM) for the analysis of nutrient elements in an edible mushroom (Ganoderma lyceum) powder has been developed (KRISS CRM 108-10-011). The mass fractions of calcium (Ca), iron (Fe), and zinc (Zn) were measured by isotope dilution inductively coupled plasma mass spectrometry (ID ICP/MS). To dissolve the fungi cell wall of mushroom consisted of chitin fibers, sample preparation method by single reaction chamber type microwave-assisted acid digestion with acid mixtures was optimized. The mean measurement results obtained from 12 sample bottles were used to assign as the certified values for the CRM and the between-bottle homogeneities were evaluated from the relative standard deviations. The certified values were metrologically traceable to the definition of the kilogram in the International System of Units (SI). This CRM is expected to be used for validation of analytical methods or quality control of measurement results in analytical laboratories when they determine the mass fractions of elements in mushroom or other similar samples.