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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Axial dispersion

Classification: Manifold process -> Axial dispersion

Citations 7

"Evidence Of Axial Diffusion Accompanied By Axial Dispersion With Zone Circulating Flow Injection And Analysis Data"
Anal. Chim. Acta 1995 Volume 309, Issue 1-3 Pages 227-239
Yoshio Narusawa* and Yuichi Miyamae

Abstract: The inter-relationships of axial and radial dispersion with FIA operating parameters are critically examined and discussed. Using a computer-simulation, the relationship between axial dispersion and analyte residence times is clarified, and a model of axial dispersion free from contributing diffusional effects is presented.

"Modeling And Optimization Studies For A Sequential Flow Based Bio-analytical System"
Anal. Chim. Acta 1998 Volume 359, Issue 1-2 Pages 157-171
Sameer Parab, Bernard J. Van Wie*, Ian Byrnes, Edgar J. Robles, Bruce Weyrauch and Thomas O. Tiffany

Abstract: The clinical applications of the sequential flow technique are emphasized in this study by considering glucose determinations in a standard blood chemical analysis. The sequential flow configuration is modeled to predict experimental behavior. A rigorous theoretical formulation of the model is presented incorporating temperature relationships for the hydrodynamic and kinetic parameters. A comparisons of model predictions with experiments show agreement satisfactory for determining optimal design strategies. To perform this analysis, factorial design results of model predictions are used to locate regions where a full set of model predictions should be made. Also, experimental results and theoretical predictions are used to determine the best temperature for glucose determinations
Glucose Blood

"Decisive Problems Of Zone-circulating Flow Injection Analysis And Its Solution"
Talanta 1998 Volume 45, Issue 3 Pages 519-529
Yoshio Narusawa* and Yuichi Miyamae

Abstract: Although experiment and computer anal. of zone-circulating flow injection analysis (ZCFIA) data were studied, there are still some essential problems inherent to ZCFIA. Computer program of high dimensional modified simplex method was used for resolving peaks of ZCFIA damped response curves. Peaks are resolved from the criterion that each area of the peak surrounded by the curve and the abscissa is equal, because each sample zone circulates repeatedly in the manifold in equal volume As a result, the peaks of the damped response curve were resolved into each component and the curve obtained by summing these components is equal to the original response curve. By following up the data anal. of ZCFIA, there were many conflicts in the manual anal. of data by Li. At least, the dispersion in a flow system should not be studied by ZCFIA, and it might be studied by the single-line manifold of FIA.

"Enzymic Substrate Determination By Flow Injection Analysis In Stopped-flow Modus Using A Single Five-port Valve For Sample And Reagent Injection"
Fresenius J. Anal. Chem. 1992 Volume 343, Issue 2 Pages 183-187
Bettina Schweizer Contact Information, Hanswilly Müller and Wolfgang Böhme

Abstract: The title technique was demonstrated by the determination of ethanol with alcohol dehydrogenase. Both sample and reagent were successively injected into the carrier stream using only one value, thus saving reagent consumption and analysis time. They were sufficiently mixed by axial dispersion as shown by simulation experiments with a dye solution. The peristaltic pumps were stopped when the reaction zone was located in the flow cell, thus minimizing background signals and other interferences, and the change of absorbance with time was monitored. The calibration graph was rectilinear for 1 to 10 mg L-1 of ethanol. The technique combined the sensitivity, precision, speed and easy handling of flow injection analysis with the selectivity of enzymatic reactions and was successfully used to determine ethanol in several beverages. The determination of ethanol with alcohol dehydrogenase is described as an example of enzymatic determination with the flow injection analysis system (FIAS). Both sample and reagent are successively injected into the carrier stream by using only one valve. Compared with other techniques, the principle described is more economical with regard to reagent consumption and anal. time. Basic experiments on this kind of reagent addition (dispersion, reproducibility, possibility for gradient dilution) were made by simulation with dye solution The determination of ethanol is carried out using the stopped-flow technique. The peristaltic pumps are stopped when the reaction zone is located in the flow cell, and the change of absorbance with time is monitored. Thus background signals and other matrix influences can be minimized. The method is tested under real conditions for the determination of alcohol in several beverages.
Ethanol Beverage

"Pulsed Flow Chemistry. A New Approach To The Generation Of Concentration Profiles In Flow Analysis"
Anal. Commun. 1998 Volume 35, Issue 3 Pages 97-101
Xue D. Wang, Terence J. Cardwell, Robert W. Cattrall and Graeme E. Jenkins

Abstract: Pulsed flow chemical (PFC) is described as a new approach to automated online anal. chemical In contrast to existing flow-based anal. chemical methods, PFC is characterized by pulsed flow, turbulent mixing and low axial dispersion. The PFC system is fully computerized and all operations are under software control. Consequently, most flow analysis methods (e.g., flow injection, continuous-flow, flow titration, etc.) can be selected with a simple click of the mouse. The system is easily miniaturized and portable which makes it particularly suited to field instrumentation. The system has been tested using several flow-based techniques including online titration for the determination of calcium in waters with potentiometric detection and a calcium ion sensor.
Calcium Environmental Potentiometry

"Development Of The Rotation Mixing Technology For Approaching To Plug-flow In A FIA Reaction Tube"
Bunseki Kagaku 1998 Volume 47, Issue 7 Pages 411-415
Kiyoshi Hirakawa, Masashi Nishida, Isao Yoshida and Daido Ishii

Abstract: The new technol. for approaching plug flow in a flow injection analysis was developed. A flexible fused SiO2 capillary of 0.35 mm outer diameter as the axis of rotation was inserted into a Teflon-made reaction tube of 1.0 mm inner diameter, 100 cm length. A plug containing the sample and reagents was mixed only in the radius direction, and did not mix in the stream direction, and the resulted stream was changed into a plug flow. The obtained FIA signal was improved to be a sym., such as a Gauss curve.

"Axial Dispersion Of Sample Zone By Analysing Damped Curved With Zone Circulating Flow Injection Analysis"
J. Flow Injection Anal. 1994 Volume 11, Issue 1 Pages 68-78
Li, Y.S.;Narusawa, Y.

Abstract: The relationships between axial dispersion and FIA parameters obtained from the analyzes of damped response curves by zone circulating FIA are discussed. Proposed equations are evaluated and their discrepancies discussed.