• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2827-2829
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• 2009

• Korean Journal of Environmental Agriculture
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• v.31 no.3
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• pp.255-263
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• 2012

BACKGROUND: The analysis for the concentration and enantiomeric ratio of OCPs have been performed to confirm the distribution and to emonstrate the pollution characteristics of chiral OCPs in ambient air. METHODS AND RESULTS: In ambient air at coastal and inland sites, concentrations and enantiomer fractions (EFs) of heptachlor (HEPT), eptachlor epoxide (HEPX), trans-chlordane (TC), cis-chlordane (CC), xychlordane (OXY), 2,4'-DDT, 2,4'-DDD with HRGC/HRMS were investigated to understand source and distribution of chiral organochlorine pesticides (OCPs) in ambient air. The mean concentrations of OCPs in ambient air were at the range of 0.027(heptachlor)~1.279 (4,4'-DDT) pg/m3 and 0.0005 (heptachlor)~0.1043 ng/g d.w. (TC), respectively. The mean EFs of OCPs in ambient air were at the range of 0.73 (HEPX)~0.45 (CC). Both preferential depletions of (+) and (-) enantiomer were observed for CC, indicated by EFs either <0.5 or >0.5, while preferential depletions of (-) enantiomer which mean EFs <0.5 were observed for chiral OCPs except TC and MC-5. CONCLUSION: OCPs in ambient air have been distributed from soil, but some of them such as chlordane, DDT etc. might have been introduced by long-range atmospheric transport, considering EFs by chiral analysis and trajectory analysis.

• KSBB Journal
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• v.26 no.4
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• pp.323-327
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• 2011

The convenient derivatization method of chiral amino alcohols as 9-anthraldimine Schiff base derivatives for chiral resolution was developed and the liquid chromatographic enantiomer separation of chiral amino alcohols as 9-anthraldimine derivatives was investigated on several coated and covalently bonded polysaccharide-derived chiral stationary phases (CSPs). In general, the performance of Chiralcel OD-H (or Chiralcel OD) (${\alpha}$ = 1.24-2.89), the coated CSP derived from cellulose derivative was superior to the other CSPs for resolution of 9-anthraldimine derivatives of several amino alcohols. The results of enantioseparation depending on the structure of 9-anthraldimine analytes like the steric bulky group and the polar moiety etc were discussed. The analytical method was applied to measure the enantiomeric purity of commercially available chiral amino alcohols. It is expected that the convenient analytical method will be very efficient for determination of enantiomeric purity of amino alcohols as 9-anthraldimine Schiff base derivatives with strong UV absorption.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.285-291
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• 2004

A simulated moving bed (SMB) chromatography system is a powerful tool for preparative scale separation, which can be applied to the separation of chiral compound. We have de-signed our own lab-scale SMB chromatography using 5 HPLC pumps, 6 stainless steel columns and 4 multi-position valves, to separate a racemic mixture of ketoprofen in to its enantiomers. Our design has the characteristics of the low cost for assembly for the SMB chromatography and easy repair of the unit, which differs from the designs suggested by other investigators. It is possible for the flow path through each column to be independently changed by computer control, using 4 multi-position rotary valves and 5 HPLC solvent delivery pumps. In order to prove the operability of our SMB system, attempts were made to separate the (S)-ketoprofen enantiomer from a ketoprofen racemic mixture. The operating parameters of the SMB chromatography were calculated for ketoprofen separation from a batch chromatography experiment as well as by the triangle theory. With a feed concentration of 1 mg/mL, (S)-ketoprofen was obtained with a purity of 96% under the calculated operating conditions.

• KSBB Journal
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• v.27 no.4
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• pp.232-236
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• 2012

Comparative liquid chromatographic enantiomer separation of ${\alpha}$-amino acids, their esters and primary amino compounds was performed using two chiral stationary phases (CSPs) prepared by covalently bonding (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-TA) of the same chiral selector. In general, the separation factors and resolution factors for these analytes on CSP 1 were greater than on CSP 2, while these capacity factors on CSP 2 were quite greater than on CSP 1. Except for leucine methyl ester and phenylalanine methyl ester, the elution orders of all analytes including ${\alpha}$-amino ${\alpha}$-alkyl acids and phenylglycine alkyl esters on CSP 1 are identical to those on CSP 2. This study showed that different connecting structures for these two CSPs might influence their ability to resolve the analytes depending on their structures related to the chiral recognition mechanism.

• KSBB Journal
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• v.27 no.3
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• pp.167-171
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• 2012

A convenient liquid chromatographic enantiomer separation of several ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives on covalently immobilized chiral stationary phases (CSPs) derived from polysaccharide derivatives was developed. The benzophenone imine derivatives of ${\alpha}$-amino acid esters were readily prepared by stirring benzophenone imine and the ${\alpha}$-amino acid ester hydrochloride salts in 2-propanol. The chromatographic conditions used on all CSPs were 0.5% or 5% 2-propanol/hexane (V/V) as the mobile phases at 1 mL/min of flow rate and UV 254 nm detection. The performance of Chiralpak IC among all CSPs was superior to that of the other CSPs for resolution of benzophenone imine derivatives of ${\alpha}$-amino acid esters. It is expected that the developed analytical method will be useful for enantiomer resolution of other ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives.

• Journal of the Korean Chemical Society
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• v.25 no.5
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• pp.306-310
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• 1981

Induced circular dichroism spectra of racemic cobalt(III) complexes for $[Co(en)_3]^{3+},\;[Co(tn_)3]^{3+},\;cis-[Co(NH_3)(en)_2]^{3+},\;[Co({\beta}-ala)(en)2_]^{2+},\;[Co(gly)(en)_2]^{2+}\;and\;[Co(acac)(en)_2]^{2+}$ were measured when they were dissolved in aqueous d-tartrate2- solution at room temperature. Only a single negative CD spectrum was observed for all the complexes above in visible region(400∼500nm). It was interpreted that these CD bands were attributed to the difference in interaction between ${\Lambda}$-and ${\Delta}$-enantiomers with d-tartrate$^{2-}$. Namely, when d-tartrate$^{2-}$ was added to ${\Lambda}$-enantiomer and ${\Delta}$-enantiomer, it caused ${\Lambda}$-enantiomer to change greatly and ${\Delta}$-enantiomer to change only slightly; combined the results proved induced circular dichroism. The enantiomer for which the eluent has a stronger affinity should be eluted faster in ion-exchange column chromatography. It is possible to predict the elution order of chromatography from the sign of the induced CD if stronger interaction of chiral anion with the complex leads to greater change in the natural CD spectrum of the complex. The elution order was in complete agreement with the prediction from the sign of the induced CD spectrum for all the measured complexes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.874-880
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• 2006

The volatile compounds of Zingiber officinale Roscoe were extracted by simultaneous steam distillation and extraction (SDE) method and identified with gas chromatigraphy/mass spectrometer (GC/MS) analysis. Enantiomeric compositions of chiral compounds were determined by multidimensional gas chromatography/mass spectrometer (MDGC/MS). A total of 57 compounds were indentified and quantified, including zingiberene, ${\beta}-sesquiphellandrene$, ${\beta}-bisabolene$, $(E,E)-{\alpha}-farnesene$ and ${\alpha}-curcumene$. Among them, zingiberene (38.41%) was founds as the predominantly abundant component. ${\alpha}-Pinene$ and nerolidol in dried ginger were detected by high enantiomeric purity (>96%) for (S)-form, and ${\beta}-pinene$ was detected only (R)-form. The enantiomeric composition of ${\alpha}-terpineol$ revealed 72.0% for (R)-form, and linalool and 4-terpineol showed mixtures of both enantiomers. (S)-Enantiomer was the major enantiomer of limonene having enatiomeric excess of 17.2%. Hence the enantiomeric composition of these compounds can be used as parameter for authenticty control of Zingiber officinale.

• 대한임상약리학회:학술대회논문집
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• 1995.06a
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• pp.21-21
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• 1995

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.165-166
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• 2002