• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.279-284
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• 2008

We investigated whether carboxylate exudation of Brassica pekinensis Rupr. was affected by nitrate deposition from simulated acid rain. A gas chromatographic (GC) analysis was employed for the determination of low molecular weight organic acids (LOA) in rhizosphere soils, bulk soil, roots and leaves of Brassica pekinensis Rupr.. Rhizosphere soils were collected after 8 weeks of plant growth by first removing the bulk soil from the root system and then by mechanical move off the rhizosphere soil that adhered to the root surface with soft brush. Soil and plant materials were simultaneously extracted with the mixture of methanol and sulfuric acid (100:7, v/v). Seven organic acids, oxalic, malonic, fumaric, succinic, maleic, L-malic and citric acid were identified and quantified by GC equipped with FID. Oxalic, L-malic, and citric acids were found in both the bulk and rhizosphere soils, while most LOAs were not detected in the control treatment. On the contrary, except maleic acid, all other organic acids were detected in the leaves and roots of cabbages treated with nitrate deposition.

• Analytical Science and Technology
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• v.10 no.5
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• pp.332-342
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• 1997

Fifteen volatile organic pollutants were spiked in blank water at the concentration of $20{\mu}g/L$ and analyzed with Purge and Trap and GC/MS. As a result, the overall mean recovery of 100% was obtained with a mean relative standard deviation of 3.6%. The method detection limits were in the range of $1.9{\sim}3.3{\mu}g/L$. In the wastewater analysis of Banwol dyeing comlex, 15 organic compounds were identified and three of these were quantified. Among the compounds identified, only trichloroethylene and tetrachloroethylene are regulated in wastewater by the Korea Ministry of Environment. But, the concentration of these two compounds were below the government allowance level.

• Analytical Science and Technology
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• v.30 no.2
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• pp.68-74
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• 2017

The volatile components in 'Fuji' apple were effectively determined by a headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). A total of 48 volatile components were identified and tentatively characterized based on National Institute of Standards and Technology (NIST) MS spectra library and the Kovats GC retention index I (RI). The harvested Fuji apples were divided into two groups: 1-methylcyclopropene (1-MCP) treated and non-treated (control) samples for finding important indicators between two groups. The major volatile components of both apples were 2-methylbutyl acetate, hexyl acetate, butyl 2-methylbutanoate, hexyl butanoate, hexyl 2-methylbutanoate, hexyl hexanoate and farnesene. No significant differences of these major compounds between 1-MCP treated and non-treated apples were observed during 1 month storage. Interestingly, the amount of off-flavors, including 1-butanol and butyl butanoate, in 1-MCP treated apples decreased over 5 months, and then increased after 7 months. However, non-treated apples did not show significant changes for off-flavors during 7 month storage (p<0.05). The non-treated apples also contained the higher levels of two off-flavors than 1-MCP treated apples. These two compounds, 1-butanol and butyl butanoate, can be used as quality indicators for the quality evaluation of Fuji apple.

• The Korean Journal of Community Living Science
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• v.23 no.2
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• pp.199-206
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• 2012

In order to evaluate the aroma compounds in Korean traditional alcoholic beverages, volatile compounds of the commercial wines, Makgeolli were analyzed and quantified using the conventional method. Eight volatile compounds including three kinds of alcohols, two kinds of organic acids and three kinds of ether were extracted by Liquid-Liquid Extraction with Dichloromethane. For the separation and quantification, Gas chromatography coupled with mass spectrometry (GC/MS) was used to analyze these compounds. Also, the separation efficiency of these compounds was performed and compared with GC column. The results of this study were as follows ; Eight kinds of volatile compounds were separated well on the HP-88 column better than on the DB-5MS column. Short chain fatty acids, butyric acid and isovaleric acid were not detected in two brands of makgeolli samples. The higher alcohols were detected in the range of 0.86~225.68 ${\mu}g/mL$ and ethyl esters were detected in the range of 0.86~225.68 ${\mu}g/mL$, respectively. There compounds are known to be associated with sensory and odorant.

• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.231-236
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• 2006

A novel sample pretreatment technique, headspace hanging drop liquid phase microextraction (HS-LPME) was studied and applied to the determination of flavors from solid clove buds by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting on HS-LPME such as organic solvent drop volume, extraction time, extraction temperature and phase ratio were investigated. 1-Octanol was selected as the extracting solvent, drop size was fixed to 0.6 $\mu$L. 60 min extraction time at 25 ${^{\circ}C}$ was chosen. HS-LPME has the good efficiency demonstrated by the higher partition equilibrium constant ($K_{lh}$) values and concentration factor (CF) values. The limits of detection (LOD) were 1.5-3.2 ng. The amounts of eugenol, $\beta$-caryophyllene and eugenol acetate from the clove bud sample were 1.90 mg/g, 1.47 mg/g and 7.0 mg/g, respectively. This hanging drop based method is a simple, fast and easy sample enrichment technique using minimal solvent. HSLPME is an alternative sample preparation method for the analysis of volatile aroma compounds by GC-MS.

• Analytical Science and Technology
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• v.20 no.4
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• pp.315-322
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• 2007

This study has been described the metabolism and excretion in a healthy male urine collected for 24 hr after oral administration of a complex (pseudoephedrine and dextromethorphan). To detect the trace amounts of parent drugs and their metabolites, acid-hydrolyzed urine was extracted and derivatized with MSTFA and MBTFA followed by gas chromatography/mass spectrometric analysis. Two parent drugs and their metabolites were tentatively identified as their derivatives based on the mass spectral interpretation and compared with previous reports. In addition, the time profile of urinary excretion rate for parent drugs and metabolites was studied. On the basis of metabolites identified and excretion rate, the metabolic pathways of both drugs are suggested.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.283-291
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• 2006

To investigate seed non destructive and fast determination technique utilizing near infrared reflectance spectroscopy (NIRs) for screening ultra high oleic (C18:1) and linoleic (C18:2) fatty acid content sesame varieties among genetic resources and lines of pedigree generations of cross and mutation breeding were carried out in National Institute of Crop Science (NICS). 150 among 378 landraces and introduced cultivars were released to analyse fatty acids by NIRs and gas chromatography (GC). Average content of each fatty acid was 9.64% in palmitic acid (C16:0), 4.73% in stearic acid (C18:0), 42.26% in oleic acid and 43.38% in linoleic acid by GC. The content range of each fatty acid was from 7.29 to 12.27% in palmitic, 6.49% from 2.39 to 8.88% in stearic, 12.59% of wider range compared to that of stearic and palmitic from 37.36 to 49.95% in oleic and of the widest from 30.60 to 47.40% in linoleic acid. Spectrums analyzed by NIRs were distributed from 400 to 2,500 nm wavelengths and varietal distribution of fatty acids were appeared as regular distribution. Varietal differences of oleic acid content good for food processing and human health by NIRs was 14.08% of which 1.49% wider range than that of GC from 38.31 to 52.39%. Varietal differences of linoleic acid content by NIRs was 16.41% of which 0.39% narrower range than that of GC from 30.60 to 47.01%. Varietal differences of oleic and linoleic acid content in NIRs analysis were appeared relatively similar inclination compared with those of GC. Partial least square regression (PLSR) among multiple variant regression (MVR) in NIRs calibration statistics was carried out in spectrum characteristics on the wavelength from 700 to 2,500 nm with oleic and linoleic acids. Correlation coefficient of root square (RSQ) in oleic acid content was 0.724 of which 72.4 percent of sample varieties among all distributed in the range of 0.570 percent of standard error when calibrated (SEC) which were considerably acceptable in statistic confidence significantly for analysis between NIRs and GC. Standard error of cross validation (SECV) of oleic acid was 0.725 of which distributed in the range of 0.725 percent standard error among the samples of mother population between analyzed value by NIRs analysis and analyzed value by GC. RSQ of linoleic acid content was 0.735 of which 73.5 percent of sample varieties among all distributed in the range of 0.643 percent of SEC. SECV of linoleic acid was 0.711 of which distributed in the range of 0.711 percent standard error among the samples of mother population between NIRs analysis and GC analysis. Consequently, adoption NIR analysis for fatty acids of oleic and linoleic instead that of GC was recognized statistically significant between NIRs and GC analysis through not only majority of samples distributed in the range of negligible SEC but also SECV. For enlarging and increasing statistic significance of NIRs analysis, wider range of fatty acids contented sesame germplasm should be kept on releasing additionally for increasing correlation coefficient of RSQ and reducing SEC and SECV in the future.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.1
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• pp.27-35
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• 2014

The headspace solid-phase microextraction (HS-SPME) followed by gas chromatography/mass spectrometry procedure has been developed for the simultaneous determination of petroleum aromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene isomers (BTEX) and polycyclic aromatic hydrocarbons (PAHs) in seawater. The advantages of SPME compared to traditional methods of sample preparation are ease of operation, reuse of fiber, portable system, minimal contamination and loss of the sample during transport and storage. SPME fiber, extraction time, temperature, stirring speed, and GC desorption time were key extraction parameters considered in this study. Among three kinds of SPME fibers, i.e., PDMS ($100{\mu}m$), CAR/PDMS ($75{\mu}m$), and PDMS/DVB ($65{\mu}m$), a $65{\mu}m$ PDMS/DVB fiber showed the most optimal extraction efficiencies covering molecular weight ranging from 78 to 202. Other extraction parameters were set up using $65{\mu}m$ PDMS/DVB. The final optimized extraction conditions were extraction time (60 min), extraction temperature (50), stirring speed (750 rpm) and GC desorption time (3 min). When applied to artificially contaminated seawater like water accommodated fraction, our optimized HS-SPME-GC/MS showed comparable performances with other conventional method. The proposed protocol can be an attractive alternative to analysis of BTEX and PAHs in seawater.

• YAKHAK HOEJI
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• v.26 no.3
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• pp.157-161
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• 1982

최근 천연물 의약품의 양약제제화와 더불어 그제제의 확인및 함량검토를 위한 공정법이 날로 그 필요성을 더해 가고 있다. 천연물 의약품은 일반 양약제제와는 달리 그 조성이 복잡하고 대부분은 그 성분조차 파악되고 있지 못한 실정이다. 더구나 일부 그 조성이 밝혀진 천연물조차 그 품종, 부위, 또는 산지등에 따라 조성이 매우 다양하므로 함량을 검토하는데는 많은 문제점을 안고 있다. 연자는 이러한 문제점을 개선하는 방법의 하나로 녹용제제를 대상으로 그 확인 및 함량 시험법을 연구하였다. 녹용은 아직까지 그 유효성분리 확실히 밝혀진 바가 없으므로 본 실험에서는 녹용중 amino acid의 pattern분석 및 glycine의 함량을 검토함으로써 확인 및 정량법을 연구하였다.

• Archives of Pharmacal Research
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• v.14 no.1
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• pp.35-40
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• 1991

(R) (+) and (S) (-) $4-^2H$-phenytoin have been used as substrates for the determination of the percentage of deuterium retention (NIH shift) after para-hydroxylation of the substrates in rat. By using GC-MS analyses, the percentages of deuterium retention were found to be 69% and 70% for the (R) and (S) phenyl rings, respectively. The results add additional evidence for the involvement of arene oxide in the oxidation of the pro (R) and pro (S) phenyls of phenytoin. The oxidation process of each ring could be mediated by independent enzyme systems, a rapid oxidative enzyme for the pro (S) phenyl and a slow oxidative enzyme for the pro (R) phenyl.