• 제목/요약/키워드: Packing Phase

검색결과 96건 처리시간 0.025초

Full validation of high-throughput bioanalytical method for the new drug in plasma by LC-MS/MS and its applicability to toxicokinetic analysis

  • Han, Sang-Beom
    • 한국독성학회:학술대회논문집
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    • 한국독성학회 2006년도 추계학술대회
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    • pp.65-74
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    • 2006
  • Modem drug discovery requires rapid pharmacokinetic evaluation of chemically diverse compounds for early candidate selection. This demands the development of analytical methods that offer high-throughput of samples. Naturally, liquid chromatography / tandem mass spectrometry (LC-MS/MS) is choice of the analytical method because of its superior sensitivity and selectivity. As a result of the short analysis time(typically 3-5min) by LC-MS/MS, sample preparation has become the rate- determining step in the whole analytical cycle. Consequently tremendous efforts are being made to speed up and automate this step. In a typical automated 96-well SPE(solid-phase extraction) procedure, plasma samples are transferred to the 96-well SPE plate, internal standard and aqueous buffer solutions are added and then vacuum is applied using the robotic liquid handling system. It takes only 20-90 min to process 96 samples by automated SPE and the analyst is physically occupied for only approximately 10 min. Recently, the ultra-high flow rate liquid chromatography (turbulent-flow chromatography)has sparked a huge interest for rapid and direct quantitation of drugs in plasma. There is no sample preparation except for sample aliquotting, internal standard addition and centrifugation. This type of analysis is achieved by using a small diameter column with a large particle size(30-5O ${\mu}$m) and a high flow rate, typically between 3-5 ml/min. Silica-based monolithic HPLC columns contain a novel chromatographic support in which the traditional particulate packing has been replaced with a single, continuous network (monolith) of pcrous silica. The main advantage of such a network is decreased backpressure due to macropores (2 ${\mu}$m) throughout the network. This allows high flow rates, and hence fast analyses that are unattainable with traditional particulate columns. The reduction of particle diameter in HPLC results in increased column efficiency. use of small particles (<2 urn), however, requires p.essu.es beyond the traditional 6,000 psi of conventional pumping devices. Instrumental development in recent years has resulted in pumping devices capable of handling the requirements of columns packed with small particles. The staggered parallel HPLC system consists of four fully independent binary HPLC pumps, a modified auto sampler, and a series of switching and selector valves all controlled by a single computer program. The system improves sample throughput without sacrificing chromatographic separation or data quality. Sample throughput can be increased nearly four-fold without requiring significant changes in current analytical procedures. The process of Bioanalytical Method Validation is required by the FDA to assess and verify the performance of a chronlatographic method prior to its application in sample analysis. The validation should address the selectivity, linearity, accuracy, precision and stability of the method. This presentation will provide all overview of the work required to accomplish a full validation and show how a chromatographic method is suitable for toxirokinetic sample analysis. A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method developed to quantitate drug levels in dog plasma will be used as an example of tile process.

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이성분계 금속합금($MoRu_3$, $MoRh_3$)의 합성 및 구조분석 (Synthesis and Structural Analysis of Binary Alloy ($MoRu_3$, $MoRh_3$))

  • 박용준;이종규;김종구;김정석;지광용
    • 분석과학
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    • 제11권3호
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    • pp.189-193
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    • 1998
  • 조사후 핵연료의 용해실험 다음에 잔류된 불용성 잔유물을 구성하는 Mo, Ru, Rh 등의 원소로 이루어진 이성분계 합금인 $MoRu_3$$MoRh_3$을 아르곤 아아크로를 이용하여 $1700^{\circ}C$ 이상의 고온에서 합성하였다. 이들 합금의 정확한 구조와 결정격자상수는 ICDD(International Centre for Diffraction Data)에서 제작되는 분말회절수집철(JCPDS files) 등에 수록된 바가 없다. X선 회절분석결과 이들 두 합금은 육방밀집구조와 $P6_3/mmc$의 공간군을 갖는 $WRh_3$의 구조와 매우 유사한 것으로 나타났다. 이 화합물들의 격자상수, a와 c는 최소자승법을 이용하여 구하였다. 또한 XPS로 분석을 통하여 이들의 표면을 조사한 결과 금속 표면이 실온에서 공기와 접촉하였을 때 여러 구성성분 중에서 Mo(0)가 Mo(6+)로 산화되는 것을 확인하였는데, 아르곤이온으로 표면을 15분 정도 sputtering 하여 Mo(6+)층을 제거할 수 있었다. 합금의 구성성분 중, Mo, Ru, Rh 원소에서 내부 전자들의 결합에너지에는 커다란 변화가 없는 것으로 나타났다. 이들 화합물들의 자화율을 측정해 본 결과 2~300 K 범위에서 전형적인 Pauli-paramagnetic 행동을 보여주었다.

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질산불용성 합금의 EPMA분석 (A Study of EPMA Analysis for Nitric Acid Insoluble Alloys)

  • 박순달;박용준;김종구;손세철;조기수
    • 분석과학
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    • 제11권6호
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    • pp.485-494
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    • 1998
  • 질산불용성합금의 특성을 갖는 Mo-Ru-Rh-Pd 합금을 만들어 XRD, WDX, EDX, ICP 분석을 하였다. XRD 분석결과 이 합금은 육방밀집(hcp) 구조와 $P6_3/mmc$의 공간군을 갖는 것으로 나타났다. EPMA 분석시 최적 가속전압은 15 kV였으며 Tc을 제외한 Zr~Cd 표준시편의 원자번호와 X-선 세기간의 직선성을 나타내는 R값은 0.998 범위였다. 내삽법에 의한 WDX 분석과 표준시편을 사용한 WDX 분석에서 구한 X-선 계수비를 비교한 결과 Mo, Pd은 표준시편을 사용한 WDX분석에 비해 0.1% 낮게 검출되었고 Ru, Rh은 약 3% 높게 검출되었다. 이 합금은 염산 12.5대 질산 1의 혼합산으로 $220^{\circ}C$, 22시간 용해시켰을 때 완전히 녹았으며 1N-HCl로 100배 희석시 재침전이 없었다. ICP 분석결과는 표준시편을 사용한 WDX분석에 대해 4% 이하의 편차를 보였다.

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저등급석탄(低等級石炭)(인도네시아 IBC)의 고정층(固定層) 반응기(反應器) 실험(實驗)을 통한 건조(乾操) 반응속도론(反應速度論) 연구(硏究) (A Study on Drying Kinetics of Low Rank Coal(Indonesia-IBC) through the Fixed-Bed Reactor Experiments)

  • 강태진;전도만;전영신;강석환;이시훈;김상도;김형택
    • 자원리싸이클링
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    • 제19권6호
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    • pp.43-50
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    • 2010
  • 에너지 위기로 인하여 석탄에 대한 관심이 증가하고 있다. 그 중에서도 저등급석탄에 대한 관심이 증가하고 있는데, 저등급석탄은 수분함량이 30~60%갱도로 수분함량이 높다. 이러한 저등급 석탄을 발전용 연료로 사용하기 위해서는 건조공정이 선행적으로 이루어져야 한다. 본 연구에서는 고정층 반응기를 이용하여 저등급석탄의 건조 반응속도론을 도출하였다. 건조반응속도는 입자크기, 주입가스 온도, 가스 유속, L/D의 영향을 변수로 하여 도출하였다. Reynold's number는 가스 유속과 석탄업자의 크기, L/D는 반응기 직경과 대상탄의 충진양을 보정하기 위해 고려하였다. 석탄의 건조 특성에서도 알 수 있듯이, 고정층 반응기를 이용한 저등급석탄의 건조에 있어서도 표면수분의 건조가 원활하며, 상 경계 반응이 적합한 메커니즘임을 확인 할 수 있었다.

설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제29권6호
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

Perfluoropolymer Membranes of Tetrafluoroethylene and 2,2,4Trifluofo- 5Trifluorometoxy- 1,3Dioxole.

  • Arcella, V.;Colaianna, P.;Brinati, G.;Gordano, A.;Clarizia, G.;Tocci, E.;Drioli, E.
    • 한국막학회:학술대회논문집
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    • 한국막학회 1999년도 The 7th Summer Workshop of the Membrane Society of Korea
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    • pp.39-42
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    • 1999
  • Perfluoropolymers represent the ultimate resistance to hostile chemical environments and high service temperature, attributed to the presence of fluorine in the polymer backbone, i.e. to the high bond energy of C-F and C-C bonds of fluorocarbons. Copolymers of Tetrafluoroethylene (TEE) and 2, 2, 4Trifluoro-5Trifluorometoxy- 1, 3Dioxole (TTD), commercially known as HYFLON AD, are amorphous perfluoropolymers with glass transition temperature (Tg)higher than room temperature, showing a thermal decomposition temperature exceeding 40$0^{\circ}C$. These polymer systems are highly soluble in fluorinated solvents, with low solution viscosities. This property allows the preparation of self-supported and composite membranes with desired membrane thickness. Symmetric and asymmetric perfluoropolymer membranes, made with HYFLON AD, have been prepared and evaluated. Porous and not porous symmetric membranes have been obtained by solvent evaporation with various processing conditions. Asymmetric membranes have been prepared by th wet phase inversion method. Measure of contact angle to distilled water have been carried out. Figure 1 compares experimental results with those of other commercial membranes. Contact angles of about 120$^{\circ}$for our amorphous perfluoropolymer membranes demonstrate that they posses a high hydrophobic character. Measure of contact angles to hexandecane have been also carried out to evaluate the organophobic character. Rsults are reported in Figure 2. The observed strong organophobicity leads to excellent fouling resistance and inertness. Porous membranes with pore size between 30 and 80 nanometers have shown no permeation to water at pressures as high as 10 bars. However high permeation to gases, such as O2, N2 and CO2, and no selectivities were observed. Considering the porous structure of the membrane, this behavior was expected. In consideration of the above properties, possible useful uses in th field of gas- liquid separations are envisaged for these membranes. A particularly promising application is in the field of membrane contactors, equipments in which membranes are used to improve mass transfer coefficients in respect to traditional extraction and absorption processes. Gas permeation properties have been evaluated for asymmetric membranes and composite symmetric ones. Experimental permselectivity values, obtained at different pressure differences, to various single gases are reported in Tab. 1, 2 and 3. Experimental data have been compared with literature data obtained with membranes made with different amorphous perfluoropolymer systems, such as copolymers of Perfluoro2, 2dimethyl dioxole (PDD) and Tetrafluorethylene, commercialized by the Du Pont Company with the trade name of Teflon AF. An interesting linear relationship between permeability and the glass transition temperature of the polymer constituting the membrane has been observed. Results are descussed in terms of polymer chain structure, which affects the presence of voids at molecular scale and their size distribution. Molecular Dyanmics studies are in progress in order to support the understanding of these results. A modified Theodoru- Suter method provided by the Amorphous Cell module of InsightII/Discover was used to determine the chain packing. A completely amorphous polymer box of about 3.5 nm was considered. Last but not least the use of amorphous perfluoropolymer membranes appears to be ideal when separation processes have to be performed in hostile environments, i.e. high temperatures and aggressive non-aqueous media, such as chemicals and solvents. In these cases Hyflon AD membranes can exploit the outstanding resistance of perfluoropolymers.

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