• Asian-Australasian Journal of Animal Sciences
• /
• 제20권10호
• /
• pp.1517-1524
• /
• 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.

• 분석과학
• /
• 제14권5호
• /
• pp.410-415
• /
• 2001

철강 시료 중의 납 분석을 위하여 수소화물 발생법을 플라스마에 납을 선택적으로 주입하고 유도결합플라스마 질량분석법으로 측정하는 분석법을 개발하였다. 납 수소화물 $PbH_4$의 생성을 위해서는 $NaBH_4$와 반응 전에 먼저 준안정 상태의 Pb(IV)로 만들어주기 위하여 산화제가 필요하다. $1000{\mu}g/mL$ 이상의 철 매질을 함유하는 시료용액으로 납 수소화물을 발생시키기 위한 최적조건을 찾는 연구를 수행하였다. 철 매질이 $10{\mu}g/mL$ 이상 존재할 때는 $K_2Cr_2O_7$이 효과적인 산화제로 작용하였으며 젖산을 가하여 감도를 향상시켰다. 시료용액의 산농도 그리고 산화제와 젖산 농도의 최적값은 철 매질의 농도에 따라 달랐다. 동위원소 희석법을 사용하여 납을 정량하였으며 철강 표준물질 NIST SRM 361, 362 분석결과는 불확도 범위안에서 검정값과 잘 일치하였다.

• 분석과학
• /
• 제23권6호
• /
• pp.524-530
• /
• 2010

클로람페니콜은 미생물과 박테리아들의 활동을 억제시킴으로써 동물 치료에 효과적인 축산 항생제 중의 하나이다. 그러나 사람에게 재생 불량성 빈혈과 같은 치명적인 부작용이 발생하여 식용으로 사육하는 동물들에 대한 클로람페니콜의 사용을 유럽을 포함한 많은 나라에서 금지하였다. 본 연구에서는 돼지고기 시료 중 클로람페니콜을 분석하기 위하여 동위원소희석 액체크로마토그래피-질량분석법(IDLC/MS/MS)을 이용하여 정확하고 정밀한 정량분석을 하였다. 돼지고기 시료중의 클로람페니콜은 에틸아세테이트로 추출하였으며, 회수율을 높이기 위하여 고체상 추출법(Solid Phase Extraction)을 이용하였다. 액체크로마토그래피/질량분석기는 전기 분무 이온화 장치(Electrospray Ionization, ESI)를 장착하여 음이 온 모드로 선택반응분석법(Selected Reaction Monitoring mode)에서 수행하였다. 클로람페니콜의 분자이온 $[M-H]^-$이온이 조각이온인 $[M-H-(HCOCl)]^-$로 가는 m/z 321 ${\rightarrow}$ 257와 동위원소의 m/z 326 ${\rightarrow}$ 262 채널을 선택하여 분석하였다. 클로람페니콜을 약 0.2, 1, 10, $25\;{\mu}g$/kg의 농도가 되도록 첨가한 돼지고기 시료로부터 제조값과 측정 분석값을 비교하여 검토한 결과, 측정값들은 불확도 범위 내에서 제조값과 일치함을 보였다. 또한 IRMM(Institute for Reference Materials and Measurement)의 클로람페니콜 분석용 돼지고기 시료인 인증 표준물질 BCR 445를 분석한 결과, 본 실험의 측정값은 불확도 범위 내에서 인증값과 일치함을 보였으며 불확도의 경우에는 IRMM이 제공한 값보다 훨씬 향상된 값을 보였다.

• Bulletin of the Korean Chemical Society
• /
• 제34권12호
• /
• pp.3817-3824
• /
• 2013

Various separation modes in HPLC, such as anion exchange (AE), reversed-phase (RP), and affinity (AF) chromatography were examined for the separation of selenium species in human blood serum and urine. While RP- and AE-HPLC were mainly used for the separation of small molecular selenium species, double column AF-HPLC achieved the separation of selenoproteins in blood serum efficiently. Further, the effluent of AF-HPLC was enzymatically hydrolyzed and then analyzed with RP HPLC for selenoamino acid study. The versatility of the hybrid technique makes the in-depth study of selenium species possible. For quantification, post column isotope dilution (ID) with $^{78}Se$ spike was performed. ORC ICP/MS (octapole reaction cell inductively coupled plasma/mass spectrometry) was used with 4 mL $min^{-1}$ Hydrogen as reaction gas. In urine sample, inorganic selenium and SeCys were identified. In blood serum, selenoproteins GPx, SelP and SeAlb were detected and quantified. The concentration for GPx, SelP and SeAlb was $22.8{\pm}3.4\;ng\;g^{-1}$, $45.2{\pm}1.7\;ng\;g^{-1}$, and $16.1{\pm}2.2\;ng\;g^{-1}$, respectively when $^{80}Se/^{78}Se$ was used. The sum of these selenoproteins ($84.1{\pm}4.4\;ng\;g^{-1}$) agrees well with the total selenium concentration measured with the ID method of $87.0{\pm}3.0\;ng\;g^{-1}$. Enzymatic hydrolysis of each selenium proteins revealed that SeCys is the major amino acid for all three proteins and SeMet is contained in SeAlb only.

• 암석학회지
• /
• 제10권3호
• /
• pp.172-178
• /
• 2001

1997읜 이후 한국기초과학지원연구원에 K-Ar 연대 측정 시스템이 도입되어 현재 이용중이다. 이 시스템은 흑연전기로, 가스 전처리 장치, 질량분석기와 자료획득장치로 구성되어 있으며 K-Ar연대 측정은 $^{38}$ Ar을 스파이크로 이용하는 동위원소 희석법에 의한 정밀한 Ar 농도 측정과 원자흡광분석을 통한 K 정량분석에의해 이루어진다. 연대가 잘 알려진 K-Ar 연대측정용 표준물질을 이용하여 시스템의 정밀성과 정확성을 확인하였다. 백만년 이하의 연대를 갖는 시료의 경우 질량분석기의 감도와 질량차별지수의 미약한 변화에도 큰영향을 받기 때문에 정확한 연대 측정이 곤란하나 중생대 및 제 3기의 K-Ar 연대를 갖는 표준시료의 연대를 측정했을 때, 믿을 만한 결과를 내고 있다. $92.6\pm$0.6 Ma의 연대가 알려진 SORI93혹운모의 경우 92.1$\pm$1.1 Ma의 연대를 얻을 수 있었고, $18.5\pm$0.6 Ma의 Bern4M 백운모는 권고치와 유사한 $17.8\pm$0.2 Ma의 연대를 얻을 수 있었다. .

• Asian-Australasian Journal of Animal Sciences
• /
• 제9권5호
• /
• pp.495-502
• /
• 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.

• 분석과학
• /
• 제18권6호
• /
• pp.520-528
• /
• 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.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권3호
• /
• pp.1-10
• /
• 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.

• Mass Spectrometry Letters
• /
• 제4권4호
• /
• pp.75-78
• /
• 2013

A gas chromatography/mass spectrometric (GC/MS) method was developed as a candidate reference method for the accurate determination of essential fatty acids (linoleic acid, ${\alpha}$- and ${\gamma}$-linolenic acids) in food supplemental oil products. Samples were spiked with three internal standards (stearic acid-$d_{35}$, $^{13}C_{18}$-linoleic acid, and $^{13}C_{18}$-${\alpha}$-linolenic acid). Samples were then subject to saponification, derivatization for methylation, and extraction by organic solvent. For GC/MS measurement, an Agilent HP-88 column, designed for the separation of fatty acid methyl esters, was selected after comparing with other columns as it provided better separation for target analytes. Target analytes and internal standards were detected by selected ion monitoring of molecular ions of their methyl ester forms. The GC/MS method was applied for the measurement of three botanical oils in NIST SRM 3274 (borage oil, evening primrose oil, and flax oil), and measurement results agreed with the certified values. Measurement results for target analytes which have corresponding isotope-labeled analogues as internal standard were calculated based on isotope dilution mass spectrometry (IDMS) approach, and compared with results calculated by using the other two internal standards. Results from the IDMS approach and the typical internal standard approach were in good agreement within their measurement uncertainties. It proves that the developed GC/MS method can provide similar metrological quality with IDMS methods for the measurement of fatty acids in natural oil samples if a proper fatty acid is used as an internal standard.

• 분석과학
• /
• 제28권6호
• /
• pp.460-466
• /
• 2015

분유 내 콜레스테롤을 정량분석하기 위한 일차분석법으로 동위원소희석 질량분석법을 개발하였다. 내부표준물질로 콜레스테롤-d₄를 사용하여 분유에 첨가하였다. 분유에 지방산과 에스테르형태로 결합되어 있는 콜레스테롤을 자유 콜레스테롤로 바꾸어주기 위해 비누화과정을 수행하였다. 비누화과정은 반응온도, 반응시간, 사용한 KOH의 농도에 따라서 최적화하였으며, 그 결과로 분유시료 0.1 g에 대해 70 ℃에서 180 분 동안 8 M의 KOH 0.8 mL를 첨가하여 반응을 진행시키는 최적화조건을 확립하였다. 이와 같은 조건으로 실험을 진행하여 재현성은 0.23%, 확장불확도는 95%의 신뢰범위에서 1.9%로 추정되었다. 확립된 동위원소희석 질량분석법의 유효화를 위해 분유내에서 콜레스테롤의 인증값을 가지는 NIST SRM을 측정하였고 이 결과가 인증값과 불확도 범위내에서 일치하는 것을 확인하였다.