University of North Florida
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Contact Info

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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Peter D. Wentzell

Abbrev:
Wentzell, P.D.
Other Names:
Address:
Trace Analysis Research Centre, Department of Chemistry, Dalhousie University, Halifax, NS, B3H 4J3 Canada
Phone:
(902) 494-3708
Fax:
(902) 494-1310

Citations 7

"An Experiment In The Sampling Of Solids For Chemical Analysis"
J. Chem. Educ. 1998 Volume 75, Issue 8 Pages 1028-1033
Robert D. Guy , Louis Ramaley and Peter D. Wentzell

Abstract: An experiment was developed to show students taking the anal. chemical lab. at the third-year level the limitations imposed by sampling in a real chemical anal. problem. The molybdenum-blue method is employed for the determination of phosphate in the presence of sodium chloride and, to facilitate rapid anal., the method is implemented as a flow injection analysis technique.
Phosphate Inorganic compound Spectrophotometry Education

"Computer-controlled Apparatus For Automated Development Of Continuous-flow Methods"
J. Autom. Methods Manag. Chem. 1989 Volume 11, Issue 5 Pages 227-234
PETER D. WENTZELL, MICHAEL J. HATTON, PAUL M. SHIUNDU, RONALD M. REE, ADRIAN P. WADE, D. BETTERIDGE, and TIMOTHY J. SLY

Abstract: The automated apparatus described is capable of controlling and/or monitoring three types of pump, two types of valve and four types of detector by means of an IBM PC-AT compatible computer. The components of the system and the interface circuitry are described; circuit diagrams are included. The apparatus has been applied in optimization of various automated analyzes (e.g., the flow injection determination of Fe) and in response surface modeling.
Iron Automation Computer Optimization Modeling Response surface

"Versatile Pump Controller For Continuous-flow Methods"
Instrum. Sci. Technol. 1990 Volume 19, Issue 4 Pages 167-180
Peter D. Wentzell; Nils G. Sundin

Abstract: A computer-driven pump controller capable of providing voltage, current and pulsed outputs for up to five pumps in analytical systems is described. The controller is ideal for situations which require remote control of speed and direction for many pumps of different types. The design is based on the Advanced Micro Devices 9513 system timer chip and provides 0-10 V, 0-25 mA and pulsed TTL outputs to control each pump. In addition, phase-locked loop circuitry allows feedback for speed regulation of certain pumps. For control of stop/start, direction or other functions, eight independently programmable TTL outputs are provided. The controller is inexpensive and designed to be driven from the parallel printer port of an IBM PC compatible computer for maximum portability. Other uses of the interface are also possible.
Computer

"Evaluation Of Acoustic Emission As A Means For Carbonate Determination"
Anal. Chim. Acta 1995 Volume 309, Issue 1-3 Pages 283-292
Michael J. Little and Peter D. Wentzell*

Abstract: Portions of 50 µL of sodium carbonate or hydrogen carbonate (I) were injected into a carrier stream (1 ml/min) of water and then mixed with 2 M HCl, the acoustics of effervescence being detected 3 cm down-stream from the mixing tee using a broad-band piezoelectric transducer over the range 0-10 kHz. Calibration curves over the range 0-1 M I were non-linear, with a detection limit of 100 mM I. I was additionally injected over a period of 3.5 min onto a basic-form 70-170 mesh Dowex 1 x 10 column (24 cm x 0.8 mm i.d.). After washing with water, 1 M HCl was passed through the column with acoustic detection 20 cm from the column head. A third system utilized reverse flow geometry, the sample being loaded on-column as before but being stripped off-column in the reverse direction with 1 M HCl. The latter geometry was preferred. Calibration graphs over the range 0-21 mM I were again non-linear with a detection limit of 1 mM I. At 5 mM I, acoustic interference from 50 mM chloride ion was minimal. At 100 mM chloride the I/HCl acoustic response was zero.
Carbonate Sensor Ion exchange Dowex Interferences

"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.
Dispersion Modeling Theory Laminar flow Random walk Peak shape

"Automated Exploration And Exploitation Of Flow Injection Response Surfaces"
Anal. Chim. Acta 1990 Volume 237, Issue 2 Pages 361-379
A. P. Wade, P. M. Shiundu and P. D. Wentzell

Abstract: Three-dimensional plots of instrumental responses vs. chemical concentration. or flow parameters were obtained with a computer-controlled flow injection system. The chemical systems studied were the photometric determination of PO43-, Pd(II), Fe(II) and S2O82-. Simplex optimization and pattern search methods for collecting response surface data are compared, and the chemical and physical effects on the surface shapes are discussed. This method of automated optimization of chemical reactions in flow analysis is critically assessed.
Automation Computer Simplex Optimization Response surface

"Response Surfaces For The Determination Of Arsenic(III) By Hydride Generation Atomic Absorption Spectrometry And Flow Injection"
Analyst 1994 Volume 119, Issue 6 Pages 1403-1411
Peter D. Wentzel, Nils G. Sundin and Cristel Hogeboom

Abstract: Response surfaces for the determination of As(III) by flow injection hydride generation AAS are reported as a function of pH and tetrahydroborate concentration for several buffers such as acetate, formate, propanoate, butanoate, citrate, phosphate and HCl. Response surfaces were obtained with an automated continuous-flow apparatus under computer control and an efficient experimental design based on continuous variations. The instrumentation and software are described. The response surfaces obtained demonstrated unexpected behavior for the pH dependence of sensitivity in the determination of As(III). The nature of the buffer was important in determining the pH dependence of the method. Results are discussed.
Arsenic(3+) Environmental Spectrophotometry