• 분석과학
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• 제8권4호
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• pp.427-434
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• 1995

Inductively coupled plasma mass spectrometry combined with the isotope dilution method is used for the determination of lithium. The isotope dilution method is based on the addition of a known amount of enriched isotope (spike) to a sample. The analyte concentration is obtained by measuring the altered isotope ratio. The spike solution is calibrated through so called reverse isotope dilution with a primary standard. The spike calibration is an important step to minimize error in the determined concentration. It has been found essential to add spike to a sample and the primary standard so that the two isotope ratios should be as dose as possible. Since lithium is neither corrosive nor toxic, lithium is used as a chemical tracer in the nuclear power plants to measure feedwater flow rate. 99.9% $^7Li$ was injected into a feedwater line of an experimental system and sample were taken downstream to be spiked with 95% $^6Li$ for the isotope dilution measurements. Effects of uncertainties in the spike enrichment and isotope ratio measurement error at various spike-to-sample ratios are presented together with the flow rate measurement results in comparison with a vortex flow meter.

• 분석과학
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• 제13권6호
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• pp.789-801
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• 2000

본 연구에서는 isotope dilution HRGC/HRMS 방법으로 저니토중의 PCDDs/PCDFs를 분석하였다. 분석결과 surrogate 표준물질의 평균 회수율은 70.1-80.8%로 양호하였다. 17종의 2, 3, 7, 8-치환이성체 분포에서는 OCDD가 총 농도의 40.6-78.5%를 나타내었으며, OCDF는 6.6-14.7%, 1, 2, 3, 4, 6, 7, 8-HpCDD는 5.1-7.7%를 나타내었다. 또한 PCDDS가 총 PCDDs/PCDFs중 62.4-86.9%를 나타내었다. TEQ 농도분포에서는 2, 3, 4, 7, 8-PeCDF가 22.7-35.6%를 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제23권11호
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• pp.1541-1544
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• 2002

The concentration of B in steels is important due to its influence on mechanical properties of steel such as hardenability, hot workability, and creep resistance. An analytical method has been developed to determine B in steel samples by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). National Institute of Standard and Technology Standard Reference Material (NIST SRM) 348a was analyzed to validate the analytical method. The steel sample was digested in a centrifuge bottle with addition of aqua regia and $^{10}B$ spike isotope. Sample pH was then adjusted to higher than 10 to precipitate most matrix elements such as Fe, Cr, and Ni. After centrifugation, the supernatant solution was passed through a cation exchange column to enhance the matrix separation efficiency. B recovery efficiency was about 37%, while matrix removal efficiency was higher than 99.9% for major matrix elements. The isotope dilution method was used for quantification and the determined B concentration was in good agreement with the certified value.

• Mass Spectrometry Letters
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• 제2권2호
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• pp.37-40
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• 2011

Saccharin is a commonly used artificial sweetener in foodstuffs. However, for its carcinogenic dispute, it has been regulated by government bodies. In this study, isotope dilution mass spectrometry (ID-MS) was introduced for the accurate quantification of saccharin. To employ ID-LC/MS, we obtained its isotope analogue, $^{13}C_1$-sodium saccharin, by customized synthesis. Samples were spiked with $^{13}C_1$-sodium saccharin and analyzed with LC/MS in negative mode. Chromatographic conditions were optimized for the adequate chromatographic retention and separation of saccharin with a $C_{18}$ column. MS was operated with electrospray ionization by the selected ion monitoring (SIM) mode of $[M-H]^-$ for saccharin (m/z 182) and $[M-Na]^-$ for its isotope analogue (m/z 183). To validate the ID-LC/MS method for accurate measurement, we prepared a batch of a candidate material by sortifying quasi-tea-drinks with saccharin and analyzed samples gravimetrically fortified in various levels of concentration. The repeatability and reproducibility of this method was tested by analyzing the reference material. Result show that ID-LC/MS is a reliable method for the quantitative analysis of saccharin.

• 분석과학
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• 제12권6호
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• pp.550-557
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• 1999

본 연구에서는 209종의 PCBs 이성체중 독성등가계수(Toxic Equivalance Factor, TEF)가 제시된 13종의 toxic-PCBs에 대하여 Isotope dilution HRCC/HRMS 방법으로 저니토중의 toxic-PCBs를 분석하였다. 분석결과 surrogate 표준물질의 회수율은 71~99%로 양호하였다. 13종의 toxic-PCBs 농도는 0.84~2.49 ng/g 범위이었으며, 이중 2,2',3,3',4,4',5-HpCB(IUPAC No. 170) 및 2,2',3,4,4',5,5'-HpCB(IUPAC No. 180) 농도가 전체 농도의 50% 정도를 나타내었으며, 2,3,4,4,5-PeCB(IUPAC No. 114)도 10% 정도를 나타내었다. 독성등가계수로 환산한 농도는 0.38~2.63 pg-TEQ/g 범위이었으며, 3,3',4,4',5-PeCB(lUPAC No. 126)가 전체의 50%를 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3482-3488
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• 2014

Matrix-induced mass bias and its effect on the accuracy of isotope ratio measurements have been examined for a quadrupole-based inductively coupled plasma-mass spectrometer (Q ICP-MS). Matrix-induced mass bias effect was directly proportional to % mass difference, and its magnitude varied for element and nebulizer flow rate. For a given element and conditions in a day, the effect was consistent. The isotope ratio of Cd106/Cd114 under $200{\mu}g\;g^{-1}$ U matrix deviated from the natural value significantly by 3.5%. When Cd 111 and Cd114 were used for the quantification of Cd with isotope dilution (ID) method, the average of differences between the calculated and measured concentrations was -0.034% for samples without matrix ($0.076{\mu}g\;g^{-1}$ to $0.21{\mu}g\;g^{-1}$ for the period of 6 months). However, the error was as large as 1.5% for samples with $200{\mu}g\;g^{-1}$ U. The error in ID caused by matrix could be larger when larger mass difference isotopes are used.

• 분석과학
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• 제16권6호
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• pp.450-457
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• 2003

사용후핵연료 내 U 및 동위원소 정량분석을 동위원소 희석 질량분석법 (isotope dilution mass spectrometry, IDMS)으로 수행하였다. 시료는 산화우라늄 사용후핵연료 시료를 $HNO_3$(1+1) 또는 이 용액과 14 M $HNO_3-0.05M$ HF 혼합용액으로 용해한 후 막 거르게 ($1.2{\mu}m$)로 여과하여 준비하였다. 시료 및 스파이크를 첨가한 시료 중의 U은 AG lX8 음이온교환 수지관에서 0.1 M HCl 용액으로 용리하였다. 시료 중의 총 U 량과 성분 동위원소 ($^{234}U$, $^{235}U$, $^{236}U$ 및 $^{238}U$)의 조성은 $^{233}U$을 스파이크로 이용하는 동위원소 희석 질량분석법으로 정량하였다. 제조한 U-233 스파이크 용액은 천연 및 감손 U을 이용한 역동위원소 희석 질량분석법 (reverse isotope dilution mass spectrometry, R-IDMS)으로 표정하였다. 동위원소 희석 질량분석법에 의한 핵연료시료 중의 총 U 량 측정결과를 전위차 적정으로 측정한 결과와 비교하였을 때 0.34% 평균 상대오차 범위에서 일치하였다.

• Mass Spectrometry Letters
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• 제5권2호
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• pp.52-56
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• 2014

Glycated hemoglobin (HbA1c) is used as an index of mean glycemia over prolonged periods. This study describes an optimization of enzyme digestion conditions for quantification of non-glycated hemoglobin (HbA0) and HbA1c as diagnostic markers of diabetes mellitus. Both HbA0 and HbA1c were quantitatively determined followed by enzyme digestion using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) with synthesized N-terminal hexapeptides as standards and synthesized isotope labeled hexapeptides as internal standards. Prior to quantification, each peptide was additionally quantified by amino acid composition analysis using ID-LC-MS/MS via acid hydrolysis. Each parameter was considered strictly as a means to improve digestion efficiency and repeatability. Digestion of hemoglobin was optimized when using 100 mM ammonium acetate (pH 4.2) and a Glu-C-to-HbA1c ratio of 1:50 at $37^{\circ}C$ for 20 h. Quantification was satisfactorily reproducible with a 2.6% relative standard deviation. These conditions were recommended for a primary reference method of HbA1c quantification and for the certification of HbA1c reference material.

• Bulletin of the Korean Chemical Society
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• 제29권11호
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• pp.2125-2128
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• 2008

• 대한화학회지
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• 제63권5호
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• pp.387-391
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• 2019