• 한국동물위생학회지
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• 제23권1호
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• pp.1-8
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• 2000

This study was carried out to simultaneous determination of penicillin G and chloramphenicol in livestock products by HPLC. The results obstained were as follows; 1. Penicillin G and chloramphenicol were analyzed by HPLC on symmetry $C_{18}$ column with acetonitrile-0.1 M phosphate buffer containing 0.0157 M thiosulfate (25 : 75) as mobile phase at UV 325nm and 280nm, respectively. 2. Samples were applied to a SeP-Pak $C_{18}$ cartridge, from which eluted penicillin derivatized with 2 M 1,2,4-triazole containing 0.001 M mercuric chloride. 3. The average recovery rates of penicillin G and chloramphenicol were 81.8% and 80.3%, respectively, and the detection limits were 5 ppb (5$\mu\textrm{g}$/kg: 7.9IU/kg) for penicillin G and chloramphenicol in porcine and bovine muscle.

• Natural Product Sciences
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• 제16권3호
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• pp.180-184
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• 2010

The simple and accurate method was established for the simultaneous determination of (-)-menthone and (-)-menthol in Menthae herba obtained from Korea and China. A quantitative analysis was performed with a gas chromatography-flame ionization detector and reference compounds were separated on a capillary HP-Innowax column (30 m $\times$ 0.23 mm, 0.50 ${\mu}m$, Agilent, MA, USA). The correlation coefficients of the compounds showed good linearity ($r^2$ > 0.9997) over the linear range. The precision, repeatability and stability showed less than 1.7% of relative standard deviation (RSD) values for two compounds. Recovery rates were within the range of 95.72 - 103.76%. The method was applied successfully to analyze 15 samples of Menthae herba and achieved sufficient and specific separation of reference compounds. The principal component analysis (PCA) exhibited the classification of 15 samples according to their locations of origin.

• 대한화학회지
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• 제38권3호
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• pp.246-253
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• 1994

미국 환경청이 지정한 129종의 priority pollutants 중 11종의 비휘발성 산성 유기화합물을 대상물질로 선정하여 토양시료 중의 극미량 분석방법을 연구하였다. 분석방법으로 기체크로토그래프/질량분석기- SIM(selected ion monitoring)법을 검출방법으로 정하고, 토양시료의 추출 및 농축방법으로 사용한 초음파 추출법(sonication extraction)과 Soxhlet(Soxhlet extraction)을 비교 연구하였다. 각 화합물의 회수율, 상대표준편차 및 method detection limit를 측정하여 EPA분석법을 대체할 수 있는지의 가능성을 조사하였다.

• 한국환경과학회지
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• 제12권10호
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• pp.1117-1120
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• 2003

Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with florisil, and finally analyzed simultaneously the organophosphorus pesticides using GC/NPD. Ultra-2 and Ultra-1 fused silica capillary columns were used to separate and identify the products. Recovery of most analytes from soybean sample, taken from pesticide residues well, was greater than(80%) for all except(6) analytes. This method can simultaneously determine multiple pesticides with a high degree of accuracy and precision.

• 환경위생공학
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• 제3권2호
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• pp.99-106
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• 1988

In order to analyze trace metals by Atomic absorption spectrophotometer in infant formula milk powder, Wet digestion method using nitric acid, perchloric acid mainly and D.D.T.C.-M.I.B.K. extraction method were done. The r-value of calibration curve were more than 0.999 in Cu, Mn, Zn. Recovery test showed high recovery rate of $97-104\%$. The results were as follows: Averages of total samples were Cu $1.92\pm1.24 ppm,\;Mn\;1.18\pm1.01ppm,\;Zn\;22.43\pm8.88ppm.$ Averages of Common Infant formula were Cu1.96\pm1.26ppm,\;Mn\;1.0\pm0.57ppm,\;Zn\;21.52\pm9.72ppm.$ Averages of follow-up infant formula were Cu$1.89\pm1.26ppm,\;Mn\;1.36\pm1.31ppm,\;Zn\;23.34\pm8.7 ppm$.

• 한국대기환경학회지
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• 제18권6호
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• pp.475-485
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• 2002

An analytical method was investigated for the meaiiurement of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) concentrations in air samples. Procedures required for column chromatographic clean up. silicagel (stage I) and gel permeation chromatography (stage II), were discussed. Identification and quantification of PCBs and OCPs were performed using a combination of gas chromatography/mass spectrometry/ selected ion monitoring. Recovery tests calculated from six samples are 68∼137% for PCBs and 58∼130% for OCPs except for endrin aldehyde. Instrumental detection limits determined for the PCBs and OCPs varied from 0.05 to 0.18 pg/m3 and from 0.71 to 16.82 pg/㎥, respectively. The method has been applied to the analysis of air samples collected at Ansung city, Kyonggi province, Korea. This method may serve as a screening protocol for the simultaneous determination of PCBs and OCPs in air.

• Membrane and Water Treatment
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• 제2권4호
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• pp.267-279
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• 2011

At steady state, the simultaneous transport of sulphuric acid and nickel sulphate through an anion-exchange membrane Neosepta-AFN (Astom Corporation, Tokyo, Japan) was investigated in a two-compartment counter-current dialyzer with single passes. The transport was quantified by the recovery yield of acid, rejection of salt and four phenomenological coefficients, which were correlated with the acid and salt concentrations in the feed. The phenomenological coefficients were determined by the numerical integration of the basic differential equations describing the concentration profiles of the components in the dialyzer. This integration was combined with an optimizing procedure. The experiments proved that the acid recovery yield is in the limits from 63 to 91 %, while salt rejection is in the limits from 79 to 97 % in the dependence on the volumetric liquid flow rate and composition of the feed.

• Journal of Pharmaceutical Investigation
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• 제21권3호
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• pp.179-188
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• 1991

An HPLC assay method of a drug to be applied to the pharmacokinetic studies of the drug should be completely validated. The validation process for an HPLC assay method in a biological sample was discussed using the data obtained from the development of HPLC method for the simultaneous quantitation of verapamil and norverapamil in human serum. The validation criteria included were specificity, linearity, accuracy, precision, sensitivity, recovery, drug stability, and ruggedness of an assay method.

• 산업경영시스템학회지
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• 제6권9호
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• pp.27-33
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• 1983

This Paper represents time-dependent stochastic variations of common discounted cash flow formulae with explicit consideration given to inflation. The cash flow, the ratio of discounting or compounding, and the rate of inflation are allowed to vary with time in a random fashion in equations for the compound amount of a single payment, present worth of a single payment, amount of an annuity, periodic deposits to accumulate a future amounts, present worth of an annuity and capital recovery And all formulae are derived for the case of discrete random variations.

• Bulletin of the Korean Chemical Society
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• 제25권11호
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• pp.1671-1675
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• 2004

A simple method for simultaneous recovery and reuse of $OsO_4$ and alkaloid ligand in the asymmetric dihydroxylation of olefins has been developed by using macroporous alkaloid resins bearing residual vinyl groups.