Benzofuran

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.


Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, Phase change data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity Value Units Method Reference Comment
Δfgas3.3 ± 0.2kcal/molCcbSteele and Chirico, 1990 

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, Phase change data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Δfliquid-8.32 ± 0.16kcal/molCcbSteele and Chirico, 1990ALS
Quantity Value Units Method Reference Comment
Δcliquid-949.03 ± 0.14kcal/molCcbSteele and Chirico, 1990Corresponding Δfliquid = -8.325 kcal/mol (simple calculation by NIST; no Washburn corrections); ALS
Quantity Value Units Method Reference Comment
liquid51.527cal/mol*KN/AChirico, Nguyen, et al., 1986DH

Constant pressure heat capacity of liquid

Cp,liquid (cal/mol*K) Temperature (K) Reference Comment
42.710298.15Chirico, Nguyen, et al., 1986T = 10 to 450 K.; DH

Phase change data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
AC - William E. Acree, Jr., James S. Chickos
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Tboil447.2KN/AWeast and Grasselli, 1989BS
Tboil444.15KN/ACooper, Crowne, et al., 1967Uncertainty assigned by TRC = 0.5 K; TRC
Tboil442.15KN/AGordy and Burrus, 1954Uncertainty assigned by TRC = 1.5 K; TRC
Tboil447.15KN/APerkin, 1896Uncertainty assigned by TRC = 0.5 K; TRC
Quantity Value Units Method Reference Comment
Δvap11.6 ± 0.05kcal/molVSteele and Chirico, 1990ALS
Δvap11.6kcal/molN/ASteele and Chirico, 1990DRB

Reduced pressure boiling point

Tboil (K) Pressure (atm) Reference Comment
335. to 336.0.020Frinton Laboratories Inc., 1986BS
439.6 to 441.0.967Buckingham and Donaghy, 1982BS
370.6 to 372.0.11Buckingham and Donaghy, 1982BS

Enthalpy of vaporization

ΔvapH (kcal/mol) Temperature (K) Method Reference Comment
11.0338.AStephenson and Malanowski, 1987Based on data from 323. to 403. K.; AC

Temperature of phase transition

Ttrs (K) Initial Phase Final Phase Reference Comment
232.000crystaline, IIcrystaline, IChirico, Nguyen, et al., 1986DH
245.482crystaline, IliquidChirico, Nguyen, et al., 1986DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


IR Spectrum

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, References, Notes

Data compiled by: Coblentz Society, Inc.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director


Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, IR Spectrum, UV/Visible spectrum, Gas Chromatography, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

Mass spectrum
For Zoom
1.) Enter the desired X axis range (e.g., 100, 200)
2.) Check here for automatic Y scaling
3.) Press here to zoom

Additional Data

View image of digitized spectrum (can be printed in landscape orientation).

Due to licensing restrictions, this spectrum cannot be downloaded.

Owner NIST Mass Spectrometry Data Center
Collection (C) 2014 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.
Origin Japan AIST/NIMC Database- Spectrum MS-NW-3084
NIST MS number 228345

All mass spectra in this site (plus many more) are available from the NIST/EPA/NIH Mass Spectral Library. Please see the following for information about the library and its accompanying search program.


UV/Visible spectrum

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, IR Spectrum, Mass spectrum (electron ionization), Gas Chromatography, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Victor Talrose, Alexander N. Yermakov, Alexy A. Usov, Antonina A. Goncharova, Axlexander N. Leskin, Natalia A. Messineva, Natalia V. Trusova, Margarita V. Efimkina

Spectrum

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

UVVis spectrum
For Zoom
1.) Enter the desired X axis range (e.g., 100, 200)
2.) Check here for automatic Y scaling
3.) Press here to zoom

Additional Data

View image of digitized spectrum (can be printed in landscape orientation).

View spectrum image in SVG format.

Download spectrum in JCAMP-DX format.

Source Lang (editor), 1961
Owner INEP CP RAS, NIST OSRD
Collection (C) 2007 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.
Origin INSTITUTE OF ENERGY PROBLEMS OF CHEMICAL PHYSICS, RAS
Source reference RAS UV No. 19762
Instrument Beckman DU
Boiling point 174

Gas Chromatography

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Kovats' RI, non-polar column, isothermal

View large format table.

Column type Active phase Temperature (C) I Reference Comment
CapillaryHP-160.969.Zhang, Li, et al., 1992N2; Column length: 25. m; Column diameter: 0.20 mm
CapillaryHP-160.969.Zhang, Li, et al., 1992N2; Column length: 25. m; Column diameter: 0.20 mm
CapillaryHP-1100.976.Zhang, Li, et al., 1992N2; Column length: 25. m; Column diameter: 0.20 mm
CapillaryOV-101140.1005.8Gerasimenko, Kirilenko, et al., 1981N2; Column length: 50. m; Column diameter: 0.3 mm

Van Den Dool and Kratz RI, non-polar column, temperature ramp

View large format table.

Column type Active phase I Reference Comment
CapillarySPB-51007.Engel and Ratel, 200760. m/0.32 mm/1. μm, 40. C @ 2. min, 3. K/min, 230. C @ 10. min
CapillaryDB-51006.0Xu, van Stee, et al., 200330. m/0.25 mm/1. μm, He, 2.5 K/min; Tstart: 50. C; Tend: 200. C
CapillaryDB-5996.Rostad and Pereira, 198630. m/0.26 mm/0.25 μm, He, 50. C @ 4. min, 6. K/min, 300. C @ 20. min

Van Den Dool and Kratz RI, non-polar column, custom temperature program

View large format table.

Column type Active phase I Reference Comment
CapillaryDB-5MS1015.Varlet V., Knockaert C., et al., 200630. m/0.32 mm/0.5 μm, He; Program: 70C(1min) => 3C/min => 80C(1min) => 5C/min => 150C => 10C/min => 280C (4min)
CapillaryHP-1986.Sing, Smadja, et al., 199250. m/0.32 mm/1.05 μm, He; Program: 20C(0.5min) => 60C => 4C/min => 250C

Van Den Dool and Kratz RI, polar column, temperature ramp

View large format table.

Column type Active phase I Reference Comment
CapillaryCP-WAX 57CB1486.Salter L.J., Mottram D.S., et al., 198860. C @ 5. min, 4. K/min; Column length: 50. m; Column diameter: 0.32 mm; Tend: 200. C
CapillaryCP-WAX 57CB1488.Whitfield, Mottram, et al., 1988He, 60. C @ 5. min, 4. K/min, 200. C @ 10. min; Column length: 50. m; Column diameter: 0.32 mm
CapillaryCP-WAX 57CB1489.Whitfield, Mottram, et al., 1988He, 60. C @ 5. min, 4. K/min, 200. C @ 10. min; Column length: 50. m; Column diameter: 0.32 mm

Van Den Dool and Kratz RI, polar column, custom temperature program

View large format table.

Column type Active phase I Reference Comment
CapillarySupelcowax-101521.Sing, Smadja, et al., 199260. m/0.25 mm/0.25 μm, He; Program: 20C(0.5min) => 60C => 4C/min => 250C

Normal alkane RI, non-polar column, isothermal

View large format table.

Column type Active phase Temperature (C) I Reference Comment
PackedPolydimethyl siloxane110.992.Ferrand, 1962 

Normal alkane RI, non-polar column, temperature ramp

View large format table.

Column type Active phase I Reference Comment
CapillaryZB-51000.Harrison and Priest, 200930. m/0.25 mm/0.25 μm, Helium, 40. C @ 1. min, 6. K/min, 280. C @ 9. min
CapillarySPB-51006.Poligné, Collignan, et al., 200160. m/0.32 mm/1. μm, He, 3. K/min; Tstart: 40. C; Tend: 200. C
CapillaryDB-1968.Lu, Yu, et al., 199760. m/0.32 mm/1. μm, He, 40. C @ 2. min, 2. K/min, 280. C @ 40. min

Normal alkane RI, non-polar column, custom temperature program

View large format table.

Column type Active phase I Reference Comment
CapillaryPolydimethyl siloxane with 5 % Ph groups1003.Robinson, Adams, et al., 2012Program: not specified
CapillaryPolydimethyl siloxane with 5 % Ph groups1007.Robinson, Adams, et al., 2012Program: not specified
CapillaryDB-5988.Yu and Zhang, 201030. m/0.25 mm/0.25 μm; Program: 40 0C (5 min) 5 0C/min -> 260 0C 15 0C/min -> 280 0C (1 min)
CapillaryHP-5995.Zhao, Li, et al., 200830. m/0.25 mm/0.25 μm; Program: 40 0C (2 min) 5 0C/min -> 80 0C 7 oC/min -> 160 0C 9 0C/min -> 200 0C 20 0C/min -> 280 0C (10 min)
CapillaryHP-51005.Zhao, Li, et al., 200830. m/0.25 mm/0.25 μm; Program: not specified
CapillaryMethyl phenyl siloxane (not specified)1007.Poligne, Collignan, et al., 2002Program: not specified
CapillaryDB-51005.Mateo and Zumalacárregui, 199650. m/0.32 mm/0.25 μm, He; Program: 40C (10min) => 3C/min => 95C => 10C/min => 270C (10min)
CapillaryPolydimethyl siloxane, unknown content of Ph-groups991.Geldon, 1989Program: not specified
CapillaryPolydimethyl siloxane, unknown content of Ph-groups996.Geldon, 1989Program: not specified

Normal alkane RI, polar column, custom temperature program

View large format table.

Column type Active phase I Reference Comment
CapillaryBP-201496.Pontes, Marques, et al., 200730. m/0.25 mm/0.25 μm, He; Program: 50C(1min) => 2.5C/min => 100C => 2C/min => 180C => 15C/min => 220C

Lee's RI, non-polar column, temperature ramp

View large format table.

Column type Active phase I Reference Comment
CapillaryHP-5153.2Wang, Hou, et al., 200730. m/0.30 mm/0.25 μm, Helium, 50. C @ 5. min, 5. K/min, 200. C @ 15. min
CapillaryHP-5153.8Shao, Wang, et al., 200630. m/0.3 mm/0.25 μm, He, 50. C @ 5. min, 5. K/min, 200. C @ 15. min
CapillaryDB-5173.42Williams and Horne, 1995He, 60. C @ 2. min, 5. K/min; Column length: 25. m; Column diameter: 0.3 mm; Tend: 270. C
CapillaryDB-5160.51Rostad and Pereira, 198630. m/0.26 mm/0.25 μm, He, 50. C @ 4. min, 6. K/min, 300. C @ 20. min

Lee's RI, non-polar column, custom temperature program

View large format table.

Column type Active phase I Reference Comment
CapillaryDB-5MS156.7Aracil, Font, et al., 2005Column length: 60. m; Column diameter: 0.25 mm; Program: not specified

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Steele and Chirico, 1990
Steele, W.V.; Chirico, R.D., Thermodynamics and the hydrodeoxygenation of 2,3-Benzofuran, Cooperative Agreement No. FC22-83FE60149 (NIPEP-457), IIT Research Institute, NIPEP, Bartlesville, OK 74005, 1990, 1-75. [all data]

Chirico, Nguyen, et al., 1986
Chirico, R.D.; Nguyen, A.; Steele, W.V.; Strube, M.M.; Hossenlopp, I.A.; Gammon, B.E., Thermochemical and thermophysical properties of organic compounds derived from fossil substances. Chemical thermodynamic properties of organic oxygen compounds found in fossil materials, NIPER Report, 1986, 135, 42p. [all data]

Weast and Grasselli, 1989
CRC Handbook of Data on Organic Compounds, 2nd Editon, Weast,R.C and Grasselli, J.G., ed(s)., CRC Press, Inc., Boca Raton, FL, 1989, 1. [all data]

Cooper, Crowne, et al., 1967
Cooper, A.R.; Crowne, C.W.P.; Farrell, P.G., Gas-Liquid Chromatographic Studies of Electron-Donor-Acceptor Systems, Trans. Faraday Soc., 1967, 63, 447. [all data]

Gordy and Burrus, 1954
Gordy, W.; Burrus, C.H., Phys. Rev., 1954, 93, 419. [all data]

Perkin, 1896
Perkin, W.H., LXIX. On Magnetic Rotatory Power, especially of Aromatic Compounds, J. Chem. Soc., 1896, 69, 1025-1257. [all data]

Frinton Laboratories Inc., 1986
Frinton Laboratories Inc., Catalog Number 11, Frinton Laboratories Inc., Vineland, NJ, 1986, 99. [all data]

Buckingham and Donaghy, 1982
Buckingham, J.; Donaghy, S.M., Dictionary of Organic Compounds: Fifth Edition, Chapman and Hall, New York, 1982, 1. [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Lang (editor), 1961
Lang (editor), L., Absorption Spectra in the Ultraviolet and Visible Region, 1961, 2, 357. [all data]

Zhang, Li, et al., 1992
Zhang, M.J.; Li, S.D.; Chen, B.J., Compositional studies of high-temperature coal tar by GC/FTIR analysis of light oil fractions, Chromatographia, 1992, 33, 3/4, 138-146, https://doi.org/10.1007/BF02275894 . [all data]

Gerasimenko, Kirilenko, et al., 1981
Gerasimenko, V.A.; Kirilenko, A.V.; Nabivach, V.M., Capillary gas chromatography of aromatic compounds found in coal tar fractions, J. Chromatogr., 1981, 208, 1, 9-16, https://doi.org/10.1016/S0021-9673(00)87953-4 . [all data]

Engel and Ratel, 2007
Engel, E.; Ratel, J., Correction of the data generated by mass spectrometry analyses of biological tissues: Application to food authentication, J. Chromatogr. A, 2007, 1154, 1-2, 331-341, https://doi.org/10.1016/j.chroma.2007.02.012 . [all data]

Xu, van Stee, et al., 2003
Xu, X.; van Stee, L.L.P.; Williams, J.; Beens, J.; Adahchour, M.; Vreuls, R.J.J.; Brinkman, U.A.Th.; Lelieveld, J., Comprehensive two-dimensional gas chromatography (GC×GC) measurements of volatile organic compounds in the atmosphere, Atmos. Chem. Phys., 2003, 3, 3, 665-682, https://doi.org/10.5194/acp-3-665-2003 . [all data]

Rostad and Pereira, 1986
Rostad, C.E.; Pereira, W.E., Kovats and Lee retention indices determined by gas chromatography/mass spectrometry for organic compounds of environmental interest, J. Hi. Res. Chromatogr. Chromatogr. Comm., 1986, 9, 6, 328-334, https://doi.org/10.1002/jhrc.1240090603 . [all data]

Varlet V., Knockaert C., et al., 2006
Varlet V.; Knockaert C.; Prost C.; Serot T., Comparison of odor-active volatile compounds of fresh and smoked salmon, J. Agric. Food Chem., 2006, 54, 9, 3391-3401, https://doi.org/10.1021/jf053001p . [all data]

Sing, Smadja, et al., 1992
Sing, A.S.C.; Smadja, J.; Brevard, H.; Maignial, L.; Chaintreau, A.; Marion, J.-P., Volatile constituents of faham (Jumellea fragrans (Thou.) Schltr.), J. Agric. Food Chem., 1992, 40, 4, 642-646, https://doi.org/10.1021/jf00016a024 . [all data]

Salter L.J., Mottram D.S., et al., 1988
Salter L.J.; Mottram D.S.; Whitfield, Volatile compounds produces in Maillard reactions involving glycine, ribose and phospholid, J. Sci. Food Agric., 1988, 46, 2, 227-242, https://doi.org/10.1002/jsfa.2740460211 . [all data]

Whitfield, Mottram, et al., 1988
Whitfield, F.B.; Mottram, D.S.; Brock, S.; Puckey, D.J.; Salter, L.J., Effect of Phospholipid on the Formation of Volatile Heterocyclic Compounds in Heated Aqueous Solutions of Amino Acids and Ribose, J. Sci. Food Agric., 1988, 42, 3, 261-272, https://doi.org/10.1002/jsfa.2740420309 . [all data]

Ferrand, 1962
Ferrand, R., Gas phase chromatography using retention indices for the analysis of tars and their hydrogenation products, Journees internationales d'etude des methodes de separation immediate at de chromatographie; Org. sur l'initiative du IX., 1962, 132-140. [all data]

Harrison and Priest, 2009
Harrison, B.M.; Priest, F.G., Composition of peaks used in the preparation of malt for Scotch Whisky production - influence of geographical source and extraction depth, J. Agric. Food Chem., 2009, 57, 6, 2385-2391, https://doi.org/10.1021/jf803556y . [all data]

Poligné, Collignan, et al., 2001
Poligné, I.; Collignan, A.; Trystram, G., Characterization of traditional processing of pork meat into boucané, Meat Sci., 2001, 59, 4, 377-389, https://doi.org/10.1016/S0309-1740(01)00090-0 . [all data]

Lu, Yu, et al., 1997
Lu, G.; Yu, T.-H.; Ho, C.-T., Generation of flavor compounds by the reaction of 2-deoxyglucose with selected amino acids, J. Agric. Food Chem., 1997, 45, 1, 233-236, https://doi.org/10.1021/jf960609c . [all data]

Robinson, Adams, et al., 2012
Robinson, A.L.; Adams, D.O.; Boss, P.K.; Heymann, H.; Solomon, P.S.; Trengove, R.D., Influence of geographic origine on the sensory characteristics and wine composition of Vitus viniferas cv. Cabernet Sauvignon wines from Australia (Supplemental data), Am. J. Enol. Vitic., 2012, 64, 4, 467-476, https://doi.org/10.5344/ajev.2012.12023 . [all data]

Yu and Zhang, 2010
Yu, A.-N.; Zhang, A.-D., The effect of pH on the total formation of aroma compounds produced by hearting a model system containing L-ascorbic acid with L-threonine/L-serine, Food Chem., 2010, 119, 1, 214-219, https://doi.org/10.1016/j.foodchem.2009.06.026 . [all data]

Zhao, Li, et al., 2008
Zhao, Y.; Li, J.; Xu, Y.; Duan, H.; Fan, W.; Zhao, G., EXtraction, preparation and identification of volatile compounds in Changyu XO brandy, Chinese J. Chromatogr., 2008, 26, 2, 212-222, https://doi.org/10.1016/S1872-2059(08)60014-0 . [all data]

Poligne, Collignan, et al., 2002
Poligne, I.; Collignan, A.; Trystram, G., Effects of salting, drying, cooking, and smoking operations on volatile compound formation and collor patterns in pork, Food Eng. Physical Properties, 2002, 67, 8, 2976-2986. [all data]

Mateo and Zumalacárregui, 1996
Mateo, J.; Zumalacárregui, J.M., Volatile compounds in chorizo and their changes during ripening, Meat Sci., 1996, 44, 4, 255-273, https://doi.org/10.1016/S0309-1740(96)00028-9 . [all data]

Geldon, 1989
Geldon, A.L., Ground Water Hydrology of the Central Raton Basin, Colorado and New Mexico, US Geological Survey, US Government Printing Office, 1989, 104. [all data]

Pontes, Marques, et al., 2007
Pontes, M.; Marques, J.C.; Camara, J.S., Screening of volatile composition from Portuguese multifloral honeys using headspace solid-phase microextraction-gas chromatography-quadrupole mass spectrometry, Talanta, 2007, 74, 1, 91-103, https://doi.org/10.1016/j.talanta.2007.05.037 . [all data]

Wang, Hou, et al., 2007
Wang, G.; Hou, Z.; Sun, Y.; Liu, Y.; Xie, B.; Liu, S., Investigation of pyrolysis behavior of fenoxycarb using PY-GC-MS assisted with chemometric methods, Chem. Anal., 2007, 52, 141-156. [all data]

Shao, Wang, et al., 2006
Shao, X.; Wang, G.; Sun, Y.; Zhang, R.; Xie, K.; Liu, H., Determination and Characterization of the Pyrolysis Products of Isoprocarb by GC-MS, J. Chromatogr. Sci., 2006, 44, 3, 141-147, https://doi.org/10.1093/chromsci/44.3.141 . [all data]

Williams and Horne, 1995
Williams, P.T.; Horne, P.A., Analysis of aromatic hydrocarbons in pyrolytic oil derived from biomass, J. Anal. Appl. Pyrolysis, 1995, 31, 15-37, https://doi.org/10.1016/0165-2370(94)00814-H . [all data]

Aracil, Font, et al., 2005
Aracil, I.; Font, R.; Conesa, J.A., Semivolatile and volatile compounds from the pyrolysis and combustion of polyvinyl chloride, J. Anal. Appl. Pyrolysis, 2005, 74, 1-2, 465-478, https://doi.org/10.1016/j.jaap.2004.09.008 . [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Gas Chromatography, References