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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Harry L. Pardue

Abbrev:
Pardue, H.L.
Other Names:
Address:
Department of Chemistry, 1393 BRWN BLDG, Purdue University West Lafayette, IN 47907-1393 USA
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Citations 9

"Improved Ruggedness For Flow-based Kinetic Methods Of Analysis"
Anal. Chim. Acta 1998 Volume 360, Issue 1-3 Pages 77-87
Yunqing Shi and Harry L. Pardue*

Abstract: This paper introduces a new approach to improve the ruggedness of flow-based kinetic determinations. After reagents and sample are mixed, the flow is stopped, signal vs. time data are recorded by an on-line computer, and curve-fitting methods are used to compute the signal that would be measured if the reaction were monitored to equilibrium. The new approach is evaluated using the Mo(VI) catalyzed oxidation of iodide to triiodide by hydrogen peroxide. Time-dependent concentrations of triiodide are monitored by changes in absorbance at 360 nm. Effects of changes in pH as well as the concentrations of iodide and Mo(VI) are evaluated using four different data-processing options, two of which were expected to exhibit poor ruggedness to changes in these variables and two of which were expected to exhibit significantly improved ruggedness. All data-processing options yielded linear calibration plots and had similar degrees of precision. As expected, the principal difference among the options was the ability to reject effects of changes in experimental variables. The new options are 10- to 70-fold less dependent on changes in pH and concentrations of iodide and molybdate than the more conventional options.
Kinetic

"Evaluation Of A Predictive Steady-state Flow Injection Method Adapted To An Open Flow Tube With A Tracer"
Anal. Chim. Acta 1995 Volume 303, Issue 2-3 Pages 199-210
Julie A. Roussin, Jianwei Li and Harry L. Pardue*

Abstract: Portions of 50-750 µL of 0.39-1.18 mM tri-iodide in a phosphate buffer of pH 6 were analyzed by FIA using flow rates in the range 16.7-31.3 µL/s, and were detected amperometrically at a potential of 200 mV using Pt electrodes. Using the data, a model is described whereby the leading edge of the response peak is processed to predict the steady-state signal that would have been obtained if sufficient undiluted sample had been used to fill the flow cell. The model correlated well with conventional peak height/area/width data processing techniques, the largest deviations from linearity being noted with peak width parameters. The technique however did require a larger minimum sample injection volume.
Iodide Amperometry Electrode Modeling Peak analysis Signal processing Peak width

"Evaluation Of A Predictive Curve-fitting Method For Processing Data From Flow Systems. 1. Flow System With A Mixing Chamber"
Anal. Chim. Acta 1993 Volume 272, Issue 1 Pages 125-134
James M. Jordan, Michael D. Love and Harry L. Pardue*

Abstract: The predictive kinetic data processing approach of Bacon and Pardue [Clin. Chem. (Winston-Salem, N. C.), 1989, 35, 360], implemented by fitting a first-order model (Pardue and Jordan, Anal. Chim. Acta, 1989, 220, 23), was evaluated with a flow system (e.g., Tyson, Ibid., 1986, 179, 131) involving tri-iodide as tracer and amperometric detection. The advantages of the described method included a tenfold reduction in the dependence of response on sample volume and a 20 to 65-fold reduction in the dependence on flow rate relative to a peak height method.
Triiodide Amperometry Mixing chamber Data acquisition Kinetic Theory

"Evaluation Of Different Data-processing Options For A Flow System With A Well-stirred Mixing Chamber"
Anal. Chim. Acta 1993 Volume 272, Issue 1 Pages 115-124
James M. Jordan, Steven H. Hoke and Harry L. Pardue*

Abstract: Various mathematical treatments already reported have been validated by use of the instrument system and reagents and the time-controlled sampling approach of Jordan and Pardue (Ibid., 1992, 270, 195) for amperometric detection of tri-iodide tracer. The calibration graphs for the time-interval and peak-height methods were rectilinear up to 2 mM and 1 mM tri-iodide, respectively.
Triiodide Amperometry Mixing Theory Well stirred mixing chamber

"Kinetic Treatment Of Unsegmented Flow Systems. 5. Comprehensive Treatment For Systems With Gradient Chamber"
Anal. Chim. Acta 1989 Volume 220, Issue 1 Pages 23-42
Harry L. Pardue and James M. Jordan

Abstract: A variable-time kinetic model is used to derive a comprehensive set of equations for an unsegmented flow system with a gradient chamber for the situations in which the analyte, reactant or product is monitored. Equations are presented for single-channel systems with excess analyte and excess reactant. These response equations are used to develop relationships that permit one to calculate whether analyte or reactant is in excess, to understand the merits and limitations of dispersion coefficients and to relate measured time intervals to initial analyte concentration for both single- and dual-channel systems. Relationships between time intervals (Δt) and the logarithm of initial analyte concentration (C) are inherently non-linear and include terms for the reference-point concentrations between which time intervals are measured. Special cases for which Δt vs. In C relationships are linear and do not include the reference-point concentrations are discussed and the assumptions that lead to these simplified equations are identified. Computed response curves are included to illustrate behavior in different phases of the processes.
Kinetic Gradient technique

"Kinetic Aspects Of Analytical Chemistry"
Anal. Chim. Acta 1989 Volume 216, Issue 1-2 Pages 69-107
Harry L. Pardue

Abstract: A review is presented, with 89 references. Methods are classified into single-component, direct computational and curve-fitting methods. Applications of kinetic methods in luminescence, potentiometric, flow injection, and chromatographic analyzes are discussed.
Luminescence Potentiometry Kinetic Review Signal processing

"Flow Injection Spectrophotometric Determination Of Glucose In Blood Plasma With Bindshedler's Green Leuco Base As Color Reagent"
Anal. Chim. Acta 1988 Volume 214, Issue 1 Pages 455-461
Masanori Akiba and Shoji Motomizu

Abstract: The hydrogen peroxide produces in the oxidation of glucos in an immobilized glucose oxidase reactor is determined by using Bindschedler's green (leuco base) as color reagent with iron(II) as catalyst; the increase in the absorbance at 725 nm is measured. For 100 µL samples, calibration was almost linear in the range 0-2.5 mg L-1 glucose; the relative standard deviation for 1 mg L-1 glucose was 0.6% (n = 10) and the detection limit (S/N = 2) was 0.02 mg L-1. The injection rate was 20 h-1. Glucose was determined satisfactorily in control sera and in real blood sera.
Glucose Blood Plasma Clinical analysis Spectrophotometry Catalysis Enzyme Merging zones

"Kinetic Treatment Of Unsegmented Flow Systems. 4. Equations For A System With Gradient Chamber Corrected To Account For Detectors With Finite Sensitivities"
Anal. Chim. Acta 1986 Volume 187, Issue 1 Pages 343-346
Paul Jager and Harry L. Pardue

Abstract: Corrected equations are presented for a flow-injection sample-processing system that includes a gradient chamber. In earlier treatments, the initial and final points of a time-interval measurement were defined to correspond to a detection system with infinite sensitivity. The more exact equations now presented account for the effects of using practical detectors with finite sensitivities. Data are presented to show that the revised equations correctly predict the curvature observed in calibration plots at low analyte concentrations.
Kinetic Gradient technique Mixing chamber Theory

"Kinetic Treatment Of Unsegmented Flow Systems. 3. Flow Injection System With Gradient Chamber Evaluated With A Linearly Responding Detector"
Anal. Chim. Acta 1986 Volume 179, Issue 1 Pages 169-179
Harry L. Pardue and Paul Jager

Abstract: The flow system was essentially as used in Parts I and II (Anal. Abstr., 1981, 41, 3J7, 3J8). The thin-layer electrochemical detector comprised a platinum working electrode and a vitreous-carbon counter-electrode at a p.d. of 200 mV. The reaction between I3- and S2O32- in phosphate buffer at pH 6.0 was studied as an example. Equations were evaluated for situations in which(I) neither the flow stream nor the gradient chamber,(II) only the flow stream and (iii) both the flow stream and chamber contained S2O32- reactant. Both calibration data and response graphs showed good agreement between theory and experiment except for(II). In(II), the theory accurately predicted the nature of the response but gave slightly longer completion times than were achieved experimentally.
Electrode Gradient technique Kinetic Modeling Theory