Biomaterial Database

Determination of diffusion coefficients by gas chromatography. 2004

George Karaiskakis, and Dimitrios Gavril

Department of Chemistry, University of Patras, 26504 Patras, Greece. g.karaiskakis@chemistry.upatras.gr

Gas chromatography (GC), apart from the qualitative and quantitative analysis of gaseous mixtures, offers many possibilities for physicochemical measurements, among which the most important is the determination of diffusion coefficients of gases in gases and liquids and on solids. The gas chromatographic techniques used for the measurement of diffusion coefficients, namely the methods based on the broadening of the chromatographic elution peaks, and those based on the perturbation of the carrier gas flow-rate, are reviewed from the GC viewpoint, considering their running though the history, the experimental arrangement and procedure, the appropriate mathematical analysis and the main results with brief discussions. The experimental data on diffusion coefficients, determined by the various gas chromatographic techniques, are compared with those quoted in the literature or estimated by the known empirical equations predicting diffusion coefficients. This comparison permits the calculation of the precision and accuracy of the techniques applied to the measurement of diffusion coefficients.

UI	MeSH Term	Description	Entries
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D002627	Chemistry, Physical	The study of CHEMICAL PHENOMENA and processes in terms of the underlying PHYSICAL PHENOMENA and processes.	Physical Chemistry,Chemistries, Physical,Physical Chemistries
D002849	Chromatography, Gas	Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.	Chromatography, Gas-Liquid,Gas Chromatography,Chromatographies, Gas,Chromatographies, Gas-Liquid,Chromatography, Gas Liquid,Gas Chromatographies,Gas-Liquid Chromatographies,Gas-Liquid Chromatography
D004058	Diffusion	The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.	Diffusions
D005740	Gases	The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)
D012680	Sensitivity and Specificity	Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)	Specificity,Sensitivity,Specificity and Sensitivity
D049672	History, 19th Century	Time period from 1801 through 1900 of the common era.	19th Century History,19th Cent. History (Medicine),19th Cent. History of Medicine,19th Cent. Medicine,Historical Events, 19th Century,History of Medicine, 19th Cent.,History, Nineteenth Century,Medical History, 19th Cent.,Medicine, 19th Cent.,19th Cent. Histories (Medicine),19th Century Histories,Cent. Histories, 19th (Medicine),Cent. History, 19th (Medicine),Century Histories, 19th,Century Histories, Nineteenth,Century History, 19th,Century History, Nineteenth,Histories, 19th Cent. (Medicine),Histories, 19th Century,Histories, Nineteenth Century,History, 19th Cent. (Medicine),Nineteenth Century Histories,Nineteenth Century History
D049673	History, 20th Century	Time period from 1901 through 2000 of the common era.	20th Century History,20th Cent. History (Medicine),20th Cent. History of Medicine,20th Cent. Medicine,Historical Events, 20th Century,History of Medicine, 20th Cent.,History, Twentieth Century,Medical History, 20th Cent.,Medicine, 20th Cent.,20th Cent. Histories (Medicine),20th Century Histories,Cent. Histories, 20th (Medicine),Cent. History, 20th (Medicine),Century Histories, 20th,Century Histories, Twentieth,Century History, 20th,Century History, Twentieth,Histories, 20th Cent. (Medicine),Histories, 20th Century,Histories, Twentieth Century,History, 20th Cent. (Medicine),Twentieth Century Histories,Twentieth Century History