• Title/Summary/Keyword: Internal standard method

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A Study on the Simultaneous Determination of Residual Zeranol, Zearalenone and Their Metabolites in Beef by Gas Chromatography/Mass Spectrometry (Gas Chromatography/Mass Spectrometry에 의한 우육 중의 잔류 Zeranol, Zearalenone 및 그 대사산물들의 동시 분석법에 대한 연구)

  • 이은섭;이용욱
    • Journal of Food Hygiene and Safety
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    • v.9 no.1
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    • pp.1-13
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    • 1994
  • A Simultaneous determination method was improved for the determination and confirmation of zeranol, zearalenone, as well as their isomers and metabolites, in beef. The analytes were extracted from tissue by CH3CN, hydrolyzed enzymatically(for glucuronide conjugates), cleaned up by a strong basic anion exchange resin combined with a liquid/liquid partitioning, derivatized using MSTFA and confirmed, quantified by GC/MS/SIM with a internal standard, zearalane. The results were as follows : (1) all the estrogens were separated on the GC/MS chromatogram under the extraction method and the chromatographic conditions improved, the retention times of zearalane-TMS2, zearalanone-TMS2, zearalenone-TMS2, zeranol-TMS3, taleranol-TMS3, and $\alpha$-zearalenol-TMS3, $\beta$-zearalenol-TMS3, were 18.49, 19.44, 19.63, 19.71, 19.79 and 19.99, 20.08 minutes, respectively. (2) The calibration curves of residual zeranol, zearalenone and their metabolites showed constantly linear(r=0.99) in the range of 5~20 ng. The minimum detection concentration of residual zeranol, zearalenone and their metabolites was 1 ppb. (3) The total average recovery of residual zeranol, zearalenone and their metabolites from spiked beef was 60.2%(CV=29.7%) at the 1 ppb and 63.5%(CV=26.5) at the 2 ppb, 72.9%(CV=18.2%) at the 4 ppb. (4) The preservation method for 6 estrogens was improved for the fast running time(21 min) and MSTFA was utilized for derivatizing 6 estrogens for improvement of recovery, for good resolution, for characteristic mass spectra unlike Jose's method and Tina's method. The utilization of zearalane as internal standard showed good quantification result for zeranol, zearalenone, as well as their isomers and metabolites, in beef.

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A study on the Assessment of Standard Wages for Constructing Luminaries for Landscope Lighting (경관조명기구의 설치에 대한 기준노임 산정에 관한 연구)

  • Yoo, Dong-Gil;Lee, Bok-Hee;Lee, Sok-Yeon
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.10a
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    • pp.169-172
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    • 2008
  • Recently, landscape lighting is more and more installing in many places such as park, cultural heritages, large-scale structures, bridges, apartment, and so on. However, there is no the government-set official estimation for standard wages constructing luminaries for landscape lighting. The cost of construction is estimated based on the standard wages of related-similar installations such as internal lighting fixtures or the designer's subjective decision. Sometimes, it is overestimated or underestimated. In this paper, the fundamental process for estimating the standard wages constructing luminaries for landscape lighting is studied. The estimation method of standard wages constructing lighting fixtures was examined on the basis of the type and capacities of luminaries, installation places, type and shapes of installation auxiliary materials, worker's skill, and etc. As a result, some results obtained in this work were significantly, different with the standard wages for internal electric wiring published by Korea Electric Association. In the future, to improve the accuracy of the estimation of the standard wages for constructing luminaries for landscope lighting, detailed factors related to the installation condition and dimensions and types of luminaries should be considered.

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Analysis of Diethylcarbamazine and Diethylcarbamazine-N-oxide by Gas Chromatography

  • Lee, Suk-Hyang;M.S;Pharm.D
    • Archives of Pharmacal Research
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    • v.19 no.6
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    • pp.475-479
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    • 1996
  • Diethylcarbamazine (DEC, 1-diethylcarbamyl-4-methylpiperazine) is an antiparasitic piperazine derivative used in the treatment of lymphatic filariasis caused by Wuchereria bancrofti, Brugia malayi or grugia timori. DEC-N-oxide is a major metabolite in humans and has antifilarial activity. In carrying out pharmacokinetic studies, gas chromatographic analysis of DEC in plasma can be complicated by the presence of the metabolite, since the thermally unstable DEC-N-oxide is converted back to a material which coelutes with DEC under the conditions of the analysis. We now report a method to separate DEC-N-oxide from DEC in plasma using solid phase extraction with subsequent gas chromatographic analysis using a nitrogen specific detector. One-diethylcarbamyl-4-ethylpiperazine (E-DEC) was the internal standard. The standard curve of DEC was linear in the range of 10 to 200 ng/ml as described by Y=0.0350+0.0128X, $R^2=0.999$. The limit of quantitation was 4 ng/mL. Reproducibility at 10, 100 and 200 ng/mL concentration points of the standard curve gave coefficient variations of 6.1%, 7.8% and 1.6%, respectively. The recovery following solid phase extraction was 99.3% for DEC and 94.8% for the internal standard. This sensitive and specific analytical method is suitable for pharmacokinetic studies of DEC.

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Method of Saliva Collection for Salivary Cortisol Measurement (타액 코티졸 측정을 위한 타액 수집 방법 조사)

  • Choi, Sanho;Lee, Ilsuk;Song, Inja;Kwon, O Jong;Park, Keeeon;Hong, Haejin;Sung, Kang-Keyng;Lee, Sangkwan
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.28 no.2
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    • pp.223-232
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    • 2014
  • Most of salivary cortisol are an unbound free form reflecting physiological function later. Thus, it is used frequently to evaluate the HPA-Axis and physiological function. Although the needs of salivary cortisol measurement in Korean Medicine is higher and higher, there are not many studies, because the reliability of salivary cortisol measurement is not high. To make the reliability high and encourage to use it in Korean Medicine, the goal of this study is to suggest the standard method of saliva collecting for cortisol measurement through the review of previous studies using salivary cortisol and to encourage to use it in clinical fields in Korean Medicine. The results are as followed; First, salivary cortisol has many benefits, i. e. easy collecting, non-invasive collecting, and reflecting the physiological function. Second, the collecting time and method are kept sternly, because the methods of saliva collecting vary depending on the goal of study. Third, the specific tools for saliva collecting are recommended to prevent contamination. In conclusion, if the standard methods of saliva collecting is kept to measure salivary cortisol, it would be very useful in many fields of Korean Medicine.

Analysis of the Internal Reliability in Relative Orientation and Independent Model Method (상호표정 및 독립모델법에서의 내적신뢰성 분석)

  • 양인태
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.5 no.1
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    • pp.59-65
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    • 1987
  • This paper presented the procedures for detecting gross errors, and described the influence of the number and distribution of points on the internal reliability in photogrammetric adjustment, such as relative orientation and independent model method. The use of the standard six points for relative orientation and the regular four points for independent model method result in low internal reliability. With such a distribution, gross erors in measured points might not be detected But using cluster of double or triple points instead of individual point, internal reliability improves remarkably.

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Stability Analysis of Seokchook Using the Design Method of Rockery (Rockery설계방법에 의한 석축의 안정성 검토)

  • Kim, Si-Nyeon;Yang, U-Sik;Baek, Yeong-Sik
    • Geotechnical Engineering
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    • v.5 no.2
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    • pp.5-18
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    • 1989
  • The Seokchook has been designed and constructed on the basis of the empirical standard cross sections depending mainly on its height. And there have been felts experimental studies to deft.Glop the analytical methods to analyze the stability of the Seokchook. Hendron presented from his experimental results a method for the design of the Rockery which is very similar to the Seokchook. This study evaluates the stability of the various standard sections of the Seokchook using Hendron's method. It is concluded that most sections are stable when the internal friction angle exceeds 30 degrees. However, when the internal friction angle is smaller than 30 degrees, there can be some limitations in making use of the standard cross sections.

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Analysis of DA-6034, a New Flavonoid Derivative in Biological Fluids by HPLC (HPLC를 이용한 생체 시료중의 새로운 플라보노이드 유도체인 DA-6034의 분석)

  • Lee, Jong-Jin;Son, Mi-Won;Yoo, Moo-Hi;Jang, Min-Sun;Kim, Won-Bae;Lee, Kang-Chun
    • YAKHAK HOEJI
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    • v.42 no.2
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    • pp.149-152
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    • 1998
  • A high performance liquid chromatographic method was developed for the determination of DA-6034 in biological fluids using internal standard. Plasma containing DA-6034 and inter nal standard was extracted by liquid-liquid extraction at an acidic pH. After evaporation of the organic layer, the drug and internal standard were reconstituted with mobile phase and injected into the column. They were separated by high performance liquid chromatography on inertsil ODS II column at 334 nm. The detection limit of DA-6034 in plasma was 0.02 ${\mu}$g/ml. In this method, the range of recovery and coefficients of variation were 96-110% and 0.40-3.78%, respectively. There was no interference from endogenous substances. Urine and bile were analysed using the deproteinization method and the detection limit of DA-6034 was 1${\mu}$g/l.

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Determination of Glimepiride in Human Plasma by Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

  • Kim, Ho-Hyun;Chang, Kyu-Young;Lee, Hee-Joo;Han, Sang-Beom
    • Bulletin of the Korean Chemical Society
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    • v.25 no.1
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    • pp.109-114
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    • 2004
  • A sensitive method for quantitation of glimepiride in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Glipizide was used as an internal standard. Glimepiride and internal standard in plasma sample was extracted using diethyl etherethyl acetate (1 : 1). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile-5 mM ammonium acetate (60:40, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS in the multiple reaction monitoring (MRM) mode, glimepiride and glipizide were detected without severe interference from human plasma matrix. Glimepiride produced a protonated precursor ion ([M+H]$^+$) at m/z 491 and a corresponding product ion at m/z 352. And the internal standard produced a protonated precursor ion ([M+H]]$^+$) at m/z 446 and a corresponding product ion at m/z 321. Detection of glimepiride in human plasma by the LC-ESI/MS/MS method was accurate and precise with a quantitation limit of 0.1 ng/mL. The validation, reproducibility, stability, and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of glimepiride in human plasma.

A Study on the Rapid Construction Method for Ground Excavation (지반굴착을 위한 급속시공 방안 연구)

  • Sim, Jae-Uk;Son, Sung-Gon;An, Hyung-Jun;Kim, In-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1251-1258
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    • 2008
  • The purpose of this research is to introduce the new temporary earth retaining wall system using landslide stabilizing piles. This system is a self-supported retaining wall(SSR) without installing supports such as tiebacks, struts and rakers. The SSR is a kind of gravity structures consisting of twin parallel lines of piles driven below dredge level, tied together at head of soldier piles and landslide stabilizing piles by beams. There are three types of excavation wall structures: standard method for medium retained heights(<8.0m), internal excavation method and slope excavation method for deep-excavation applications(>8.0m). In the present study, the measured data from seven different sites which the SSR was used for excavation were collected and analyzed to investigate the characteristic behavior lateral wall movements associated with urban excavations in Korea.

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Lactulose Contents in Market Milks (시판 우유중의 Lactulose 함량)

  • 박영희;홍윤호
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.19 no.4
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    • pp.330-334
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    • 1990
  • The lactulose contents in market milks were analyzed by gas chromatographic method. The method is evaluated for accurac and reproducibility using phenyl-$\beta$-D-glucoside as an internal standard. The response factor(RF) of lactulose of standard mixture was 1.15 the recoveries were 97.4-101.3% and the reproducibility was determined on the coefficeitns of variation 24.8% for pasteurized milk and 4.6-4.9% for UHT milk The lactulose contents of 16 brands of the market milks determined were 5.3-59.7mg/100ml in UHT milk and 1.3-1.8mg/100ml in pasteurized milk.

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