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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Random walk

Classification: Theory -> Random walk

Citations 6

"A Random Walk Simulation Of Flow Injection Analysis"
Anal. Chim. Acta 1984 Volume 165, Issue 1 Pages 227-236
D. Betteridge, C. Z. Marczewski and A. P. Wade

Abstract: Dispersion and chemical reaction in a single-channel flow-injection system are modelled by a random walk (stochastic, Markovian chain) method using a microcomputer. The effects of various simulated physical variables are investigated. The model provides valuable insight into the mixing process in flow injection analysis.

"A Random Walk Simulation Of Flow Injection Systems With Merging Zones"
Anal. Chim. Acta 1987 Volume 194, Issue 1 Pages 49-60
C. D. Crowe and H. W. Levin, D. Betteridge and A. P. Wade

Abstract: A flow-injection system with merging zones is simulated by using a random-walk stochastic (Markovian chain) model. Variables studied include reagent plug size and offset, reagent concentration and flow rate, injection delay time, reaction stoichiometry, rate constant, diffusion constants, viscosity, and temperature. The reaction of Ca(II) with o-cresolphthalein complexone was used to compare simulated and experimental results. In general, there was good agreement among computed and measured results.
Calcium Spectrophotometry

"Sequential Injection: A New Concept For Chemical Sensors, Process Analysis And Laboratory Assays"
Anal. Chim. Acta 1990 Volume 237, Issue 2 Pages 329-343
Jaromir Ruzicka and Graham D. Marshall

Abstract: The role of the random walk model in flow injection analysis is discussed and the principles of sequential injection analysis and its application to sensor injection are outlined. The design of a sequential injection analyzer. suitable for process analysis and laboratory applications is presented. This new approach to automated analysis is aimed at filling a gap in present flow injection methodology.
Sensor

"Random Walk Simulation Of Flow Injection Analysis. Evaluation Of Dispersion Profiles"
Anal. Chim. Acta 1993 Volume 278, Issue 2 Pages 293-306
Peter D. Wentzell*, Michael R. Bowdridge, Elizabeth L. Taylor and Craig MacDonald

Abstract: The random walk model was used to simulate peak shapes in FIA for the case of dispersion in straight tubes with laminar flow (no reaction). The peak profiles obtained were compared with experimental and other theoretical results. Agreement was favourable, although there were some differences from experimental results. The results show that the model is as effective as others for modeling peak shapes and that modifications to flow parameters can be incorporated easily for testing physical models.

"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.

"3-dimensional Molecular Simulation Of Chromatographic Separations"
J. Chromatogr. A 1996 Volume 722, Issue 1-2 Pages 3-17
Victoria L. McGuffin* and Peiru Wu

Abstract: A three-dimensional stochastic computer simulation has been developed in order to provide a detailed understanding of chromatographic separations. In this simulation, the migration of individual molecules is established through diffusion and convection within a fluid phase that is in contact with a surface, Molecular interaction and, hence, retention may arise by partitioning into permeable surfaces or by adsorption at solid surfaces. The molecular distribution and the corresponding zone profile may be examined and characterized by means of statistical moments at any specified time or spatial position during the simulation. This simulation provides a powerful and versatile model with which to characterize transport phenomena in complex chromatographic separation systems.
HPLC