• Title, Summary, Keyword: GC/ retention index

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Identification of Coffee Fragrances Using Needle Trap Device-Gas Chromatograph/Mass Spectrometry (NTD-GC/MS)

  • Eom, In-Yong;Jung, Min-Ji
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1703-1707
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    • 2013
  • A fast and simple sampling and sample preparation device, (NTD) has been developed and applied to sample and analyze volatile components from ground coffee beans. Coffee fragrances and other volatile organic compounds (VOCs) were sampled by the NTD and then analyzed by gas chromatograph-mass spectrometry (GC/MS). Divinylbenzene (DVB) particles (80/100 mesh size) were the sorbent bed of the NTD. More than 150 volatile components were first identified based on the database of the mass library and then finally 30 fragrances including caffeine were further confirmed by comparing experimental retention indices (i.e. Kovat index) with literature retention indices. Total sampling time was 10 minutes and no extra solvent extraction and/or reconstitution step need. Straight n-alkanes (C6-C20) were used as retention index probes for the calculation of experimental retention indices. In addition, this report suggests that an empty needle can be an alternative platform for analyzing polymers by pyrolysis-GC/MS.

Flavor Components of Poncirus trifoliata (탱자(Poncirus trifoliata)의 향기성분 분석에 관한 연구)

  • Oh, Chang-Hwan;Kim, Jung-Han;Kim, Kyoung-Rae;Ahn, Hey-Joon
    • Korean Journal of Food Science and Technology
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    • v.21 no.6
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    • pp.749-754
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    • 1989
  • The essential oil was prepared by a gas co-distillation method from flavedo of Poncirus trifoliata and was analyzed by GC/ retention index (RI) and GC/MS. The essential oil prepared by a gas co-distillation gave a whole fragrance of Poncirus trifoliata. The identification of the flavor components was performed by multi-dimensional analysis using GC/RI and GC/MS. GC/RI and GC/MS were complementary to each other. In applying GC/RI for identification, it was more effective when two columns of different polarities were used. Thirty volatile flavor constituents were identified in Poncirus trifoliata. Limonene, myrcene, ${\beta}-caryophyllene,\;trans-{\beta}-ocimene$, ${\beta}-pinene$, 3-thujene and 7-geranyloxycoumarin were the major constituents and cis-3-hexenyl acetate, n-hexyl acetate, 2-methyl acetophenone, elixene and elemicine had not been reported earlier as citrus components.

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Studies on the volatile compounds of Cnidium officinale (천궁(Cnidium officinale)의 향기성분)

  • 이재곤;권영주;장희진;김옥찬;박준영
    • Journal of the Korean Society of Tobacco Science
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    • v.16 no.1
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    • pp.20-25
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    • 1994
  • The volatile components were extracted from root of Cnidium officinale M. by SDE(Simultaneous steam distillation and extraction) apparatus and analyzed by GC/M.5 and GC retention index matching. The experimental results revealed the presence of over 22 volatile components. Major components were cnidilide (35.1%), neocnidilids (13.4%), ligustilide (23.2%). The essential oils were separated by silica gel column chromatography(Merck 70-230mesh), and 4 fractions among 12 fractions separated had a, good aroma character.

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Standardizing GC-FID Measurement of Nonmethane Hydrocarbons in Air for International Intercomparison Using Retention Index and Effective Carbon Number Concept

  • Liaw, Sheng-Ju;Tso, Tai-Ly
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.807-814
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    • 1995
  • Accurate measurements of ozone precursors are required to understand the process and extent of ozone formation in rural and urban areas. Nonmethane hydrocarbons (NMHCs) have been identified as important ozone precursors. Identification and quantification of NMHCs are difficult because of the large number present and the wide molecular weight range encountered in typical air samples. A major plan of the research team of the Climate and Air Quality Taiwan Station (CATs) was the measurement of atmospheric nonmethane hydrocarbons. An analytical method has been development for the analysis of the individual nonmethane hydrocarbons in ambient air at ppb (v) and subppb(v) levels. The whole ambient air samples were collected in canisters and analyzed by GC-FID with $Al_2O_3$/KCl PLOT column. Our targeted for quantitative analysis 43 compounds that may be substantial contributors to ozone formation. The retention indices and molar response factors of some commercially available $C_2{\sim}C_{10}$ hydrocarbons were determined and used to identify and quantify air samples. A quality assurance program was instituted to ensure that good measurements were made by participating in the International Nonmethane Hydrocarbon Intercomparison Experiments (NOMHICE).

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Volatile flavor components of soybean pastes manufactured with traditional Meju and improved Meju (재래식 메주와 개량식 메주로 제조한 된장의 휘발성 향기성분)

  • Ji, Won-Dae;Lee, Eun-Ju;Kim, Jong-Kyu
    • Applied Biological Chemistry
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    • v.35 no.4
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    • pp.248-253
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    • 1992
  • Volatile flavor components of soybean pastes, manufactured with traditional Meju and improved Meju, were extrated by simultaneous steam distillation-extraction apparatus and concentrated at atmosphere press. The concentrates were investigated GC-sniff evaluation by preparative gas chromatograph, and then analyzed and identified by GC/MS and Kovats retention index. Thirty nine components, including 11 alcohols, 4 aldehydes, 2 pyrazines, 4 acids, 3 fuans, 3 phenols, 3 esters, 3 hydrocarbons, 1 ketone, 5 miscellous ones were confirmed in soybean paste manufactured with traditional Meju. Twenty one components, including 4 alcohols, 2 aldehydes, 2 pyrazines, 2 acids, 1 fuan, 2 esters, 1 hydrocarbon, 2 ketones, 4 miscellous ones were confirmed in soybean paste manufactured with improved Meju. Ten components such as 3-methyl-1-butanol, 4-methyl-3-heptanol, trimethyl-pyrazine, 1-octen-3-ol, 2-furancarboxaldehyde, tetramethyl-pyrazine, benzaldehyde, 3-methyl-butanoic acid, naphthalene, 2-ethyl-3-methyl-oxetane were identified together in soybean pastes manufactured with traditional Meju and improved Meju.

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The Screening and Pattern Comparison of Organic Acids in 3 Kinds of Medicinal Herbal Extracts (3가지 약용 허브 추출물에 함유된 유기산 검색 및 조성 비교)

  • Chung, Ha-Yull;Jung, Do-Hyun;Park, Young-Joon
    • Korean Journal of Food Science and Technology
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    • v.32 no.5
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    • pp.997-1001
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    • 2000
  • The organic acids in 3 kinds of medicinal herbal extracts were screened and compared each other according to their organic acid contents by an efficient gas chromatographic method. It involves solid-phase extraction of organic acids using Chromosorb P with subsequent conversion to stable tert-butyldimethysilyl derivatives for the direct analysis by capillary column gas chromatography and gas chromatography-mass spectrometry. Total of 24 organic acids were reproducibly identified from 3 kinds of herbal extracts. When the GC profiles were simplified to their retention index spectra, characteristic patterns were obtained for each herb sample. As expected, three kinds of herbal extracts showed three distinct patterns.

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Flavor Components of the Fruit Peel and Leaf Oil from Zanthoxylum piperitum DC (초피(Zanthoxylum piperitum DC)의 과피와 잎의 방향성분)

  • Kim, Jung-Han;Lee, Kyung-Seok;Oh, Won-Taek;Kim, Kyoung-Rae
    • Korean Journal of Food Science and Technology
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    • v.21 no.4
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    • pp.562-568
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    • 1989
  • The essential oils from ripe fruit peel and leaf of Zanthoxylum piperitum DC were extracted by gas co-distillation method and analyzed by gas chromatography/mass spectrometry (GC/ MS) and retention index matching. The experimental results revealed the presence of over 100 volatile components. Major components were 1,8-cineol (25.47%), limonene (11.91%), geranyl acetate (9.01%), myrcene (6.15%) in fruit peel and citronellal (23.11%), 1,8-cineol (18.38%), citronellol (6.04%) in leaf. Among the components identified were the following; in fruit peel, ${\alpha}-pinene$ and 13 hydrocarbons, linalool and 8 alcohols, citronellal and 3 aldehydes, carvone and 2 kotones, methyl salicylate and 7 esters, and 1,8-cineol and oxides, and in leaf, ${\alpha}-pinene$ and 7 hydrocarbons, linalool and 7 alcohols, citronellyl acetate and 5 esters, citronellal and 1 aldehyde, carvone, and 1,8-cineol and 1 oxide.

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Comparative Sampling Procedures for the Volatile Flavor Components of Codonopsis lanceolata (전처리 방법에 따른 더덕(Codonopsis lanceolata)의 휘발성 향기성분 비교 분석)

  • Kim, Jung-Han;Kim, Kyoung-Rae;Kim, Jae-Jung;Oh, Chang-Hwan
    • Korean Journal of Food Science and Technology
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    • v.24 no.2
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    • pp.171-176
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    • 1992
  • Volatile flavor components of Codonopsis lanceolata were extracted by gas co-distillation (GCD), solvent extraction/fractionation (SEF), and headspace sampling (HSS) methods. The extracts were analyzed by dual-capillary gas chromatography-retention index (GC-RI) and gas chromatography-mass spectrometry(GC-MS). The two extracts prepared by SEF and HSS gave more similar fragrance to the Codonopsis lanceolata than the GCD extract. The GC profiles of the SEF and HSS extracts were similar to each other except for differences in peak areas. The extract prepared by SEF gave a sweet note while the extract prepared by HSS gave a green note. The GCD extract began to give a burnt note of herb medicine with prolonged distillation. Rapid extraction of flavor components from Codonopsis lanceolata was possible in several short steps by SEF and HSS methods compared to GCD. GC-MS and GC-RI were used for peak identification. GC-RI was more effective for identification of isomers, and polar FFAP column was more suitable for identification of polar compounds. From Codonopsis lanceolata we identified 35 volatile flavor constituents, 24 of which have not been previously reported by simultaneous distillation extraction method $^{(5)}$. trans-2-Hexanal, cis-3-hexen-1-ol, trans-2-hexen-1-ol, and hexanol were considered key components of the green note and 1-octen-3-ol, the component of the fresh note. Esters, including amyl propionate, seem to be responsible for the sweet note particular to Codonopsis lanceolata.

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Isolation and Identification of Polynuclear Aromatic Hydrocarbons in Seoul Atmosphere (서울시 대기중 다핵방향족 탄화수소류의 분리 및 동정)

  • Jang, Jae-Youn;Kim, Bag-Kwang;Chung, Yong;Cho, Seong-Joon
    • Journal of Korean Society for Atmospheric Environment
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    • v.4 no.2
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    • pp.47-56
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    • 1988
  • Polynuclear aromatic hydrocarbons $(PAH_s)$ in Seoul atmosphere were isolated and identified. PAH fraction was isolated from airborne suspended particulates by solvent extraction, fractionation and thin layer chromatography. PAHs were identified by GC-MS, capillary GC, retention index and so on. About 70 major $PAH_S$ were seperated in capillary GC and 41 $PAH_s$ of those were identified.

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Dimethyl Trisulfide Produced by Bacillus sp. in Cooked Soybean

  • Ji, Won-Dae;Lee, Sang-Jun;Kim, Jong-Kyu
    • Journal of Microbiology and Biotechnology
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    • v.3 no.1
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    • pp.61-63
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    • 1993
  • The neutral fraction of whole volatile flavor compounds produced by Bacillus licheniformis SSA3 and Bacillus subtilis PM3 in cooked soybean was identified by using GC/MS and Kovats retention index. The presence of dimethyl trisulfide, which emits characteristically Korean soy sauce-like odor in traditional Korean soy sauce, in identified volatile flavor components was confirmed. Dimethyl trisulfide may be produced by Bacillus licheniformis SSA3 and Bacillus subtilis PM3 in cooked soybean.

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