• Title/Summary/Keyword: Purity assessment

Search Result 47, Processing Time 0.024 seconds

Purity assessment using quantitative NMR: establishment of SI traceability in organic analysis

  • Choi, Kihwan
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.24 no.1
    • /
    • pp.30-37
    • /
    • 2020
  • Quantitative nuclear magnetic resonance (qNMR) has been gaining attention as a purity assessment method. In particular, qNMR is recognized as the primary method to realize the Internal System of Units (SI) in organic analysis. The capability of quantitative analysis is recognized as the beginning of NMR development. NMR signals are proportional to the number of nuclei and qNMR has been used in various fields, such as metabolomics and food and pharmaceutical analysis. However, careful sample preparation and thorough optimization of measurement parameters are required to obtain accurate and reliable results. In this review, quantitative methods used in qNMR are discussed, and the important factors to be considered also introduced. The recent development of qNMR techniques including combination with chromatography and, multidimensional NMR are also presented.

Development of nitrogen and oxygen certified reference materials in 10 μmol/mol for the purity evaluation

  • Ahn, Byung Soo;Moon, Dong Min;Lee, Jin Bok;Kim, Jin Seog;Lee, Jin-Hong;Hong, Kiryong
    • Analytical Science and Technology
    • /
    • v.33 no.2
    • /
    • pp.68-75
    • /
    • 2020
  • We have developed 10 μmol/mol nitrogen and oxygen certified reference materials (CRMs) in helium, as a SI-traceable gas standard for a quantifying of impurities in pure gases for the first time in Korea. The standard gas mixtures of nitrogen and oxygen were prepared in 5000 μmol/mol and sequentially were diluted to 250 μmol/mol and 10 μmol/mol according to the gravimetric preparation. In each dilution step, two cylinders of CRMs were prepared. The verification of internal consistency among the prepared gas mixtures was performed by using GC-TCD. The amount fractions and those expanded uncertainties (k = 2) of nitrogen and oxygen in the standard gas mixtures were (10.12 ± 0.08) μmol/mol and (10.18 ± 0.08) μmol/mol for nitrogen, and (9.88 ± 0.06) μmol/mol and (9.94 ± 0.06) μmol/mol for oxygen, respectively. We have conducted a purity assessment of two commercial helium gases using developed CRMs. As the results of the purity assessment, nitrogen and oxygen were detected by (1.66 ± 0.03) μmol/mol and (0.31 ± 0.02) μmol/mol, respectively, as the impurities in one of the pure helium.

Assessment of the Purity of Emodin by Quantitative Nuclear Magnetic Resonance Spectroscopy and Mass Balance

  • Park, Sojung;Choi, Yu-Jin;Do, Giang Hoang;Seo, Eun Kyoung;Hyun, Seunghun;Lee, Dongho
    • Natural Product Sciences
    • /
    • v.25 no.3
    • /
    • pp.222-227
    • /
    • 2019
  • Quantitative nuclear magnetic resonance (qNMR) is a well-established method adopted by international pharmacopoeia for quantitative and purity analyses. Emodin is a type of anthraquinone, well known as the main active component of Fabaceae, Polygonaceae and Rhamnaceae. Purity analysis of emodin is usually performed by using the high-performance liquid chromatography (HPLC)-UV method. However, it cannot detect impurities such as salts, volatile matter, and trace elements. Using the qNMR method, it is possible to determine the compound content as well as the nature of the impurities. Several experimental parameters were optimized for the quantification, such as relaxation delay, spectral width, number of scans, temperature, pulse width, and acquisition time. The method was validated, and the results of the qNMR method were compared with those obtained by the HPLC and mass balance analysis methods. The qNMR method is specific, rapid, simple, and therefore, a valuable and reliable method for the purity analysis of emodin.

The analysis of National Assessment of Educational Achievement items using three dimensional scientific assessment framework (3차원 과학 평가틀을 활용한 국가수준 학업성취도 평가 문항 분석 -초등학교 지구과학교과를 중심으로-)

  • Kim, Eun-Jong;Han, Shin
    • Journal of the Korean Society of Earth Science Education
    • /
    • v.3 no.3
    • /
    • pp.248-256
    • /
    • 2010
  • This study analyzed National Assessment of Educational Achievement items surveying to sixth-year student in elementary school utilizing three dimentional scientific assessment framework. Study's findings are as following. Science contents territory of national level study achievements estimation were set a problem energy, substance, life, earth relatively evenly. Action territory was set a problem most 'Comprehension' territory. In the case of science situation area, 'Purity scientific situation' among 5 category appeared the most.

  • PDF

Purity Assessment of Organic Reference Materials with a Mass Balance Method: A Case Study of Endosulfan-II

  • Kim, Seung-Hyun;Lee, Joonhee;Ahn, Seonghee;Song, Young-Sin;Kim, Dong-Kyum;Kim, Byungjoo
    • Bulletin of the Korean Chemical Society
    • /
    • v.34 no.2
    • /
    • pp.531-538
    • /
    • 2013
  • A mass balance method established in this laboratory was applied to determine the purity of an endosulfan-II pure substance. Gas chromatography-flame ionization detector (GC-FID) was used to measure organic impurities. Total of 10 structurally related organic impurities were detected by GC-FID in the material. Water content was determined to be 0.187% by Karl-Fischer (K-F) coulometry with an oven-drying method. Non-volatile residual impurities was not detected by Thermal gravimetric analysis (TGA) within the detection limit of 0.04% (0.7 ${\mu}g$ in absolute amount). Residual solvents within the substance were determined to be 0.007% in the Endosulfan-II pure substance by running GC-FID after dissolving it with two solvents. The purity of the endosulfan-II was finally assigned to be ($99.17{\pm}0.14$)%. Details of the mass balance method including interpretation and evaluating uncertainties of results from each individual methods and the finally assayed purity were also described.

Mass Balance Method for Purity Assessment of Organic Reference Materials: for Thermolabile Materials with LC-UV Method

  • Lee, Joonhee;Kim, Byungjoo
    • Bulletin of the Korean Chemical Society
    • /
    • v.35 no.11
    • /
    • pp.3275-3279
    • /
    • 2014
  • A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

Application of cold isostatic pressing method for fabrication of SoG-Si powder compacts (태양전지급 폴리실리콘 성형체 제작을 위한 CIP법의 활용)

  • Lee, Ho-Moon;Shin, Je-Sik;Moon, Byung-Moon;Kwon, Ki-Hwan;Kim, Ki-Young
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2009.06a
    • /
    • pp.126-129
    • /
    • 2009
  • In this study, it was aimed to develop the re-use technology of ultra-fine silicon powders, by-products during the current production process of high purity poly-Si feedstock. For this goal, the compacts of the silicon powders were tried to fabricate by CIP (Cold Isostatic Pressing) method using silicon rubber mold without chemical binder materials. The density ratio of the silicon powder compacts reached 74%. In order to simulate the actual handling and charging conditions of feedstock material in casting process, a shaking test was carried out and mass loss measured. Finally, the silicon powder compacts were melted using a cold crucible induction melting method and the purity assessment was conducted by Hall effect measurement.

  • PDF

Consolidation and casting technology of fine poly-Si powders for economical production of Si ingot (경제적인 Si 잉곳 생산을 위한 poly-Si 미세분말의 성형과 용해주조기술)

  • Moon, Byung-Moon;Kim, Bong-Hwan;Shin, Je-Sik;Lee, Sang-Mok;Park, Gi-Seong;Kim, Dae-Suk;Kim, Ki-Young
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2007.06a
    • /
    • pp.261-264
    • /
    • 2007
  • In this study, the consolidation and casting processes of fine Si powders, by-products of making high purity Poly-Si rods in the current method, were systematically investigated for use as economical solar-grade feedstock. Morphology, size, and contamination type of the poly-Si fine powders were inspected by combined analysis of SEM, particle size analyzer, and FT-IR. Poly-Si powder compacts were tried to fabricate by a consolidation process without a binding agent and then their density ratio and strength were evaluated. Finally, the electrical resistivity of the specimens prepared by an electromagnetic casting method was examined for purity assessment.

  • PDF

The performance assessment of PSA process using combined dynamic simulation (혼합사건 동적모사를 이용한 PSA공정 성능 평가)

  • Na, Kwang-Sam;Moon, Il;Han, Jae-Sung
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1996.10b
    • /
    • pp.432-435
    • /
    • 1996
  • The performance of one-column isothermal PSA process is assessed by dynamic simulator, gPROMS. The four-step and five-step processes are compared. A five-step process is employed in order to show the effect of the addtional cocurrent depressurization step on the four-step PSA process. Two processes parameters, purity and recovery of SO$_{2}$ are used for the performance comparison. The results of dynamic simulation show that four-step process is superior to five-step process in recovery, but not in purity.

  • PDF