• The Korean Journal of Nuclear Medicine
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• v.20 no.1
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• pp.75-83
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• 1986

Various TSH RIA kit components were prepared. Conditions for $^{125}I$ labelling of h-TSH were optimized by diminishing the amount of chloramine-T, ertending reaction time and lowering reaction temperature. Yield, specific activity, and immunological activity could be maintained moderately under such mild reaction conditions. The mixture of polyethyleneglycol(PEG) and second antibody worked effectively as a B/F separation agent. Even though the mixture was made with more diluted PEG and second antibody than those of using the sole component separately, the tine required for the B/F separation was shorter in case of using the mixture. The sequential saturation technique was efficient than those of applying ordinary equilibrium saturation technique in assay sensitivity and assay precision points of view.

• Economic and Environmental Geology
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• v.17 no.3
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• pp.171-177
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• 1984

Representative sulphide samples from the Sangdong skarn orebody and quartz veins show relatively narrow ranges of sulphur isotope values ranging from $^+5.5$ to $^+6.9$ permil and average $^+5.0$ permil with a standard deviation of 0.77 permil. Much higher temperature isotopic temperatures than homogenization temperatures may indicate even minerals in contact did not form together in isotopic equilibrium. Under conditions of formation of the skarn and quartz veins, ${\delta}^{34}\;H_2S$ ranges from $^+4.5$ to $^+5.3$ permil, suggesting a magmatic origin for the sulphur. Carbon and oxygen isotope values seem to show some of the spread of increasing ${\delta}^{13}C$ values of the interbedded limestone with distance from the central zone of the Sangdong mineralization. Negative values of ${\delta}^{13}C$ fluids appear to be typical of many ore deposits including those of magmatic origin. Calculated ${\delta}^{18}C$ values of the fluids are typical of those derived from magmatic sources.

• Mass Spectrometry Letters
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• v.8 no.3
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• pp.49-52
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• 2017

Ibuprofen is one of the most popular analgesic and antipyretic drugs. An isotope dilution mass spectrometry method based on LC/MS was developed as a candidate reference method for the accurate determination of ibuprofen in pharmaceutical tablets. Isotope labelled ibuprofen, $ibuprofen-d_3$, was added as an internal standard into sample extracts. Ibuprofen and $ibuprofen-d_3$, was analysed by LC/MS in a selected ion monitoring (SIM) mode to detect ions at m/z 205 and 208, respectively. The repeatability and reproducibility of the developed ID-LC/MS method were tested for the validation and assessment of metrological quality of the method.

• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.219-222
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• 2001

Separation of lithium isotopes was investigated by chemical ion exchange with a hydrous manganese(IV) oxide ion exchanger using an elution chromatography. The capacity of manganese(IV) oxide ion exchanger was 0.5 meq/g. The heavier lithium isotope was enriched in the solution phase, while the lighter isotope was enriched in the ion exchanger phase. The separation factor was determined according to the method of Glueckauf from the elution curve and isotopic assays. The separation factor of $^6Li^+$-$^7Li^+$ isotope pair fractionation was 1.018.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3618-3623
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• 2011

This paper presents a stable isotope chemistry of bone collagen and carbonate. Bone carbonate has the potential to provide additional isotopic information. However, it remains controversial as to whether archaeological bone carbonate retains its original biogenic signature. I used a novel application of bone density fractionation and checked the integrity of ${\delta}^{13}C_{apa}$ values using radiocarbon dating. Diagenesis in archaeological bone carbonate still remains to be resolved in extracting biogenic information. The combined use of bone density fractionation and differential dissolution method shows a large shift in the ${\delta}^{13}C_{apa}$ values. Although ${\delta}^{13}C_{apa}$ values are improved in lighter density fractions, a large percentage of contamination in bone carbonate was reported via $^{14}C$ dating compared to that noted with bone collagen.

• BMB Reports
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• v.33 no.6
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• pp.506-509
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• 2000

To obtain Cytochrome $c_3$ labeled with a stable isotope, the conditions of cultivation and the composition of medium for DvMF were examined. The growth of DvMF was steady and reproducible under purging with $N_2$ and under pH control. DvMF was able to go on a defined medium without natural products. The composition of the medium containing a small amount of $NH_4Cl$ as sole nitrogen source was established. Then, uniformly $^{15}N-labeled$ Cytochrome $c_3$ was obtained during the culture of DvMF in a defined medium with $^{15}NH_4Cl$; it was confirmed by $^{1}H-^{15}N$ HMQC.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.174.2-174.2
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• 2013

사이클로트론에서 가속된 70 MeV 양성자 빔은 stripper에서 인출된 후 ISOL 표적에 조사하게 된다. 이 때 희귀동위원소를 생산하기 위한 ISOL 표적의 온도는 평균 $2,000^{\circ}C$ 5%로 유지하여야 한다. 사용하고자 하는 원판형태의 우라늄 표적은 직경이 45 mm 이므로 50 mm 이상의 균일한 양성자 빔이 필요하다. 본 연구에서는 stripper에서부터 ISOL 표적 까지 빔전송에 필요한 최적 조건을 연구하였다. 총 길이는 15 m 이며 두 개의 dipole을 사용하여 빔을 90도 전환시키며 3개의 4중극전자석을 사용하였다. ISOL 표적에 균일한 빔을 조사하기 위해 wobbling 방법을 활용하여 직경 50 mm 의 균일빔을 발생하고자 한다. 빔 전송 프로그램 TRANSPORT을 이용하여 stripper에서 wobbler 전까지의 빔 광학을 계산한 결과를 보고자 하고 TRANSPORT의 결과를 TURTLE 프로그램에 적용시켜 ISOL 표적에서의 균일도를 5% 미만으로 유지하는 최적조건을 발표한다.

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.96-101
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• 1989

The infrared multiphoton decomposition of trichloroethylene-H(TCE-H) and trichloroehtylene-D(TCE-D) was studied by using the high power $CO_2$ laser. The pressure dependence of TCE-H decomposition showed that the HCl elimination channel to form ClC ≡ CCl was the major step at high pressures, while the HC ≡ CCl formation step became important at low pressures. $Cl_2C$ = CHCl ${\rightarrow}$ (high pressure) ClC ${\equiv}$ CCl + HCl ${\rightarrow}$ (low pressure) HC ${\equiv}$ CCl + 2Cl${\cdot}$($Cl_2$) The IRMPD of TCE-H and TCE-D mixtures with 10P(20) laser line showed that optimum conditions of large isotope selectivity were the low system pressures and high laser powers. The experimentally observed dependence of the branching ratios on the pressure and laser fluence, and the isotope selectivity coefficients were quantitatively explained by using the modified energy grained master equations (EGME) model.

• Bulletin of the Korean Chemical Society
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• v.2 no.1
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• pp.24-28
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• 1981

Theoretical studies of the sodium cation binding and the isotope hydration effects on the static model compound B-DNA have been qualitatively elucidated by using empirical potential energy functions. In the first place, the sodium cations bound to phosphate anions and their hydration scheme have been optimized and have given a reasonable agreement with other theoretical results and experimental studies. In the second stage, the isotope effect on the hydration through the substitution of $D_2O\;for\;H_2O$ has been carried out by the same procedure. The stabilization of B-DNA has been explained and compared in terms of the sodium cation binding to phosphate anions and its hydration in both cases of $H_2O\;and\;D_2O$.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.570-574
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• 2001

Magnesium isotope separation was investigated by chemical ion exchange with the 1-aza-12-crown-4 bonded Merrifield peptide resin using an elution chromatographic technique. The capacity of the novel azacrown ion exchanger was 1.0 meq/g dry resin. The heavier isotopes of magnesium were enriched in the resin phase, while the lighter isotopes were enriched in the solution phase. The single stage separation factor was determined according to the method of Glueckauf from the elution curve and isotopic assys. The separation factors of $^{24}Mg^{2+}$-$^{25}Mg^{2+}$, $^{24}Mg^{2+}$-$^{26}Mg^{2+}$, and $^{25}Mg^{2+}$-$^{26}Mg^{2+}$ were 1.008, 1.019, and 1.006, respectively.