• 약학회지
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• 제39권3호
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• pp.283-288
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• 1995

Rapid gas chromatographic profiling method was applied to saliva from healthy subjects for the analysis of free organic acids. Saliva samples were first saturated with NaHCO$_{3}$ and extracted with diethyl ether. The aqueous phase was solid-phase extracted using Chromosorb P as the adsorbent and diethyl ether as the eluent after the acidification and NaCl saturation, followed by triethylamine treatment. The resulting tiiethylammonium salts of acids were directly converted into stable tert.-butyl-dimethylsflyl derivatives, with subsequent analysis by dual-capiuary column gas chromatography and gas chromatograpy -mass spectrometry. From the ten saliva samples studied, twenty eight free organic acids including various fatty acids, hydroxy acids, dicarboxylic acids, md aromatic acids were tentatively identified. Among the acids identified , the concentration of lactic acid was highest for five saliva samples while $\alpha$-hydroxyisocaproic acid was most abundant for me sample, and succinic acid and glycolic acid for two samples. respectively. When the GC profiles were simplified to the corresponding acid retention index spectra of bar graphical form, they presented characteristic patterns for each individual.

• Bulletin of the Korean Chemical Society
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• 제31권3호
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• pp.678-682
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• 2010

A doubly tethered chiral stationary phase (CSP) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid were applied to the liquid chromatographic resolution of racemic tocainide, an antiarrhythmic agent, and its analogues. The chiral recognition efficiency of the doubly tethered CSP for tocainide and its analogues was generally greater than that of the corresponding singly tethered CSP especially in terms of the resolution ($R_S$). The resolution of tocainide and its analogues on the doubly tethered CSP were dependent on the content and the type of the organic and acidic modifiers in aqueous mobile phase and the column temperature. Especially, the retention behaviors of analytes on the doubly tethered CSP with the variation of the content of organic modifier in aqueous mobile phase were opposite to those on the corresponding singly tethered CSP and these opposite retention behaviors were rationalized by the lipophilicity differences of the two CSPs.

• Journal of Microbiology and Biotechnology
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• 제7권4호
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• pp.258-261
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• 1997

For the efficient production of lysophospholipid the hydrolysis of phospholipid using phospholipase $A_1$ from Serratia sp. MK1 was studied in an aqueous-solvent, a two-phase and an emulsion system. Judged on the basis of productivity and the degree of hydrolysis, the yield of lysophospholipid in a two-phase system was found to be better than that obtained in an emulsion system. Among the 13 organic solvents tested phospholipase $A_1$ showed the most efficient catalytic activity and stability in butyl acetate. When 20% phospholipid was used it was completely hydrolyzed in this two-phase system.

• KSBB Journal
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• 제6권3호
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• pp.281-288
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• 1991

This research was carried to investigate the effects of several organic solvents on the enzymatic transphosphatidylation in emulsion and two-phase solvent systems. The solvents having a similar dielectric constant with diethylether were effective for the enzyme activity. Diethylether and butylacetate were the most effective solvents, when added 12-15%(v/v) and 10-40%(v/v), respectively, for the synthesis of phosphatidylglycerol, phosphatidylethyleneglycol and phosphatidylpropyleneglycol. In the emulsion system, the size of ovolecithin liposome was increased and the clearness of the phospholipid bilayer was reduced as increasing the diethylether concentration. In the twophase solvent system, the rapidest reaction was obtained when water-organic solvent ratio was close to 1. The ratio of aqueous phase. however, should be lowered to 37% to gain the sole product of transphosphatidy1ation, without phosphatidohydrolysis.

• 대한화학회지
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• 제34권4호
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• pp.352-359
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• 1990

생화학적으로 주요한 유기산들을 신속히 분석 확인할 수 있는 효율적인 가스크로마토그래피 분석법을 개발하였다. 본 방법에서는 고형흡착제로서 Chromosorb P와 용출용매로서 diethyl ether를 사용하여 수용성 시료로부터 유기산을 고체상 추출한 후 triethylamine으로 처리하였다. 생성된 유기산들의 triethylammonium염을 직접 tert-butyldimethylsiyl 유도체로 전환시킨 후 극성이 다른 DB-5와 DB-1701 두 capillary column 분석 후 측정된 각 유기산들의 retention index (RI)와 area ratio (AR)값을 가지고 컴퓨터 RI library조사와 AR 비교를 하였을 때 신속히 유기산을 동정할 수 있었다. 본 방법은 다양한 복합 시료들의 유기산 분석을 하는데 응용될 수 있을 것이다.

• 한국환경과학회지
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• 제6권3호
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• pp.277-283
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• 1997

SPME deuce was applied to determine the THM in an aqueous solution. The 6 kinds of THM was quantitatively detenuned by using GC-ECD which has the sample eutracted on the SPME fiber from an aqueous solution for 10 min. The THM components were well separated from $CHCl_3$ to the last $CHBr_3$ UHh 13 mons at the condition. 6 kinds of the volatile halogenated organic compounds: $CHCl_3$, $CHBrCl_2$, $CHBrtCl_2$, $CHCl_3$, $C_2Cl$. and $CHBr_3$, showed well defirled calibration graph with good llnearlty from a few ppb level up to several tens of pub concentration. $CHBr_2Cl$ and $C_2C1_4$ were detected from a few samples among the 10 of river samples. CHCl3, however, was detected In 4 sea water samples with the highest of 10 ppd among the pouuted 6 positions. Trace level of $CHBr_2Cl$ and few pub level of $CHBr_3$ were also detected at the other two sample stations. Most of the 13 rain water samples collected from 6 sampling stations were contained ppd level of $CHCl_3$, and also $CHBr_2Cl$, and C_2Cl_4$ were only detected at trace level at a few rain samples among them. We could recognize the fact that our Ut and water enoronment has already been contaminated by certain volatile halogenated organic compounds through this study.

• 공업화학
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• 제4권2호
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• pp.300-307
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• 1993

$Na_2S_2O_4$ 수용액과 $CCl_4$-toluene 용액의 2상에서 유기상에 용해하는 tricaprylmethylammonium chloride 상이동 촉매를 사용하여 methyl methacrylate의 라디칼 중합속도를 측정하여, 액-액 불균일계 접촉계면을 통한 라디칼 중합반응기구를 해석하였다. MMA의 중합속도는 수용액상에 존재하는 $Q^+$ 이온의 농도와 ${S_2O_4}^{-2}$ 이온의 농도의 제곱근에 정비례하고 $CCl_4$와 MMA의 농도에 각각 정비례하였다.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.911-915
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• 2003

Two liquid chromatographic chiral stationary phases (CSPs) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid were successfully applied in the resolution of racemic tocainide and its analogues. In the resolution of tocainide, especially, the CSP containing N-CH₃ amide tethering groups was quite effective, showing clear baseline resolution (RS: 2.66) with reasonable enantioselectivity ( a: 1.25). Consequently, the CSP containing N-CH₃ amide tethering groups is expected to be useful to monitor the enantiomeric composition of tocainide in clinical samples. In addition, the chromatographic behaviors for the resolution of tocainide and its analogues on the two CSPs were found controllable by varying the content and the type of organic and acidic modifiers in aqueous mobile phase.

• Macromolecular Research
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• 제17권2호
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• pp.72-78
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• 2009

Size control of therapeutic carriers in drug delivery systems has become important due to its relevance to biodistribution in the human body and therapeutic efficacy. To understand the dependence of particle size on the formation condition during nanoprecipitation method, we prepared nanoparticles from biodegradable, amphiphilic block copolymers and investigated the particle size and structure of the resultant nanoparticles according to various process parameters. We synthesized monomethoxy poly(ethylene glycol)-poly($\varepsilon$-caprolactone) block copolymer, MPEG-PCL, with different MPEG/PCL ratios via ring opening polymerization initiated from the hydroxyl end group of MPEG. Using various formulations with systematic change of the block ratio of MPEG and PCL, solvent choice, and concentration of organic phase, MPEG-PCL nanoparticles were prepared through nanoprecipitation technique. The results indicated that (i) the nanoparticles have a dual structure with an MPEG shell and a PCL core, originating from self-assembly of MPEG-PCL copolymer in aqueous condition, and (ii) the size of nanoparticles is dependent upon two sequential processes: diffusion between the organic and aqueous phases and solidification of the polymer.

• 분석과학
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• 제33권4호
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• pp.169-176
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• 2020

Separation of basic compounds using reverse phase chromatography on a silica-based stationary phase represents a major challenge, because of the interaction between the cationic sites of the basic compounds with the anionic silanols of the stationary phase. This study presents a simple, reliable, and organic solvent - free liquid chromatographic method for the determination of terbutaline and salbutamol, in which a room temperature ionic liquid (RTIL) is used as mobile phase additive. We investigated various mobile phase parameters affecting the retention of the two compounds, such as types and concentration of RTILs and, pH of the mobile phase were investigated. The developed method was validated according to International Conference on Harmonization (ICH) guidelines and successfully applied effectively to determine salbutamol sulfate in pharmaceutical preparations.