University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Permeation

Classification: Manifold process -> Permeation

Citations 5

"Membrane Extraction Combined With Thermodesorption Gas Chromatography And Mass Selective Detection For The Analysis Of Volatile Organic Compounds In Water"
J. High Resolut. Chromatogr. 1999 Volume 22, Issue 4 Pages 205-212
Barbara Hauser, Peter Popp

Abstract: The range of application of a commercial thermodesorption-cryofocusing unit connected to a gas chromatograph/mass selective detector was extended to water analysis by using it in conjunction with membrane extraction. A flow of nitrogen passes through a silicone hollow fiber immersed in the water sample and extracted volatile organic compounds are enriched in a sorption tube mounted on top of the extraction cell. The sorption tube is then placed in the thermodesorption unit and analyzed by GC/MS. The optimal extraction parameters of this combined method were found to be 30 min extraction at 20°C with a stirring speed of 1,250 rpm and a flow rate of 100 mL/min nitrogen using a silicone hollow fiber of 0.3 m length. Under these conditions the reproducibility of the method was 5.2-10.5% RSD, The linear dynamic range of the optimized method spans three orders of magnitude and detection limits were found to be 0.02-0.1 µg/L for cis/trans-1,2-dichloroethene, benzene, trichloroethene, chlorobenzene, bromobenzene, ethylbenzene, 1,1,2,2-tetrachloroethane, and 1,2/1,4-dichlorobenzene. The method was found to be suitable for compounds with boiling points up to 220°C as memory effects increased considerably from dichloro-to hexachlorobenzene, Highly contaminated groundwater samples were analyzed. Quantitative results corresponded well with those achieved with conventional headspace-GC/FID.

"An Integrated Microdistillation Flow Injection System For Ammonia Measurement"
Anal. Lett. 1999 Volume 32, Issue 9 Pages 1847-1865
. Lane; C. W. K. Chow; D. E. Davey; D. E. Mulcahy; S. McLeod

Abstract: The development of an online ammonia pre-concentration system based on microdistillation is reported. The combination of microdistillation and flow injection gives rise to an improved analytical technique. This method has good throughput (15-20 samples per hour), requires a small sample volume (6.0 ml) and has a low detection limit (2 µg/l). Microdistillation brings the further advantage of using a pH electrode, non-specific for ammonia, as the sensing device. Evaluation of the method showed excellent correlation with the standard phenate method, and good precision for ammonia determination.

"Selective Transport Of Lanthanides Through Supported Liquid Membranes Containing Non-selective Extractant, Di-(2-ethylhexyl)phosphoric Acid, As A Carrier"
J. Memb. Sci. 2000 Volume 168, Issue 1-2 Pages 175-181
Josef Doležal, Carlos Moreno, Aleš Hrdlička and Manuel Valiente

Abstract: Permeation of lanthanides (Ln) between aqueous nitrate solutions of different acidity through supported kerosene membrane containing di-(2-ethylhexyl)phosphoric acid (DEHPA) as a carrier has been studied. Mass transfer of Ln cations has been determined in terms of permeability coefficients (P) by on-line FIA measurement of metal concentrations in strip solution. Acidity of feed solution ranged from pH 1.2 to 4.2 (ionic strength 0.1 mol L-1 (HNO3, NaNO3)) while that of strip solution was kept constant at 0.1 mol L-1 HNO3. Carrier concentration has been changed in the range from 10 to 10(3) mmol L-1. Both, the P versus feed pH plots measured at low and at high DEHPA concentrations as well as P versus DEHPA concentration plots exhibited maxima. Permeability coefficients were decreasing when advancing in the lanthanide series and significant differences in behavior of individual lanthanides has been observed. The conditions of separation of light and heavy lanthanides and mutual separation of light lanthanides have been suggested. Based on these and previous results, composition of transported species, presence of maxima on measured curves, and formation of gel-like substance in feed solution and on membrane-feed solution interface are discussed.

"Spectrophotometric Flow Injection Determination Of Ethanol In Distilled Spirits And Wines Involving Permeation Through A Silicon Tubular Membrane"
Anal. Sci. 1998 Volume 14, Issue 5 Pages 1005-1008
Ivanildo L. MATTOS, Raquel P. SARTINI, Elias A. G. ZAGATTO, Boaventura F. REIS and Maria Fernanda GINÉ

Abstract: A concentric tubing reactor comprising an inner silicone tube and an outer polyethylene tube was assembled in a manifold for flow injection determination of ethanol in beverages. The number of potential interferents was restricted by mol. size, and permeation and chemical reaction are allowed to occur along the entire chemical path. For a typical sample with an ethanol content of 40.3%, the relative standard deviation (n=7) was 3.7%.
Ethanol Spirit Wine Spectrophotometry

"A Fundamental Study On The Spectrophotometric Determination Of Hydrogen Peroxide By Membrane Permeation/flow Injection Analysis And Its Application To Glucose"
J. Flow Injection Anal. 1992 Volume 9, Issue 1 Pages 78-83
Hitsuko OSHIMA, Masahiro SANADA and Shoji MOTOMIZU

Abstract: The permeation unit designed by us was incorporated with a flow injection spectrophotometric system. Hydrogen peroxide was determined by using membrane permeation of iodine which was generated by oxidation of iodide with hydrogen peroxide. Iron(II) accelerated the generat ion of iodine. Iodine permeated reacted with N,N-diethyl-p-phenylenediamine to form red purple product. Absorbances of the product were measured at 550 nm. A calibration graph was rectilinear up to 4 x 105M. This method was applied to the determination of D-glucose using the flow system coupled with an immobilized enzyme column. By the addition of 5 ppm of glucose in the buffer solution stream, a calibration graph was rectilinear from 0 to 20 ppm, and the detection limit was 0.6 ppm of glucose.
Glucose