University of North Florida
Browse the Citations
-OR-

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

View Stuart Chalk's profile on LinkedIn

Calorimetry

Classification: Calorimetry

Citations 19

"Pulsed Bed Calorimetry: A Jump In Speed And Sensitivity"
J. Therm. Anal. Calor. 1997 Volume 49, Issue 2 Pages 1089-1096

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
S. Walter, A. Hadj Mebarek and S. Diyani

Abstract: Conventional calorimetry has always the difficulty of choosing between near to equilibrium working conditions and high thermal ramp rates. Thus, either the transport phenomena and sample homogeneities are good but the signals become weak due to thermal losses, or the signals are sharp, but strong gradients across the sample lead to chemical and thermal heterogeneities. The described pulsed fluidized bed technique, by strongly stirring the sample, allows good sample homogeneities even at high ramp rates. Moreover, the permanently regenerated cover gas allows as well a good heat transfer towards the thermocouples as a constant atmosphere composition leading to very precise onset temperatures.
Mercury Inorganic compound

"Sequential Flow Injection Analysis Based On Calorimetric Detection"
Thermochim. Acta 1999 Volume 337, Issue 1-2 Pages 27-38

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
A. Wolf, A. Weber, R. Hüttl, J. Lerchner and G. Wolf

Abstract: A calorimetrically based sequential flow injection method with enzyme catalyzed reactions is proposed and demonstrated. In contrast to multi-detection devices with immobilized enzymes miniaturized flow-through reaction calorimeters are used as sensing device with independent substrate and toggled enzyme solution flows. From the sequence of the heat power signals information about composition of the substrate is obtainable. A reasonable application of the method requires miniaturized calorimeters. Different constructions of flow-through reaction calorimeters based on silicon chips with integrated thermopiles as heat power transducers have been analyzed with respect to their sensitivities and mixing behavior. As an application the analysis of saccharides containing mixtures is discussed.
Sucrose Glucose Maltose Fructose Microfluidic

"Determination Of Hydrogen Peroxide For Application In Aerobic Cell Systems Oxygenated Via Hydrogen Peroxide"
Anal. Chim. Acta 1983 Volume 155, Issue 1 Pages 47-56

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Hans Lundbäck and Gillis Johansson, Olle Holst

Abstract: A flow injection method has been developed for monitoring H2O2 during the production of dihydroxyacetone from glycerol with use of immobilized Gluconobacter oxydans. The sample (5 µL) is injected into 0.2 M Na acetate (pH 5) and diluted 100-fold in a dispersion coil, and the H2O2 is determined amperometrically by oxidation at +1.2V (vs. the s.c.e) at a flow-through vitreous-carbon electrode. Calibration graphs were rectilinear for 0.1 to 100 mM H2O2. Potential interference by other sample components (e.g., dihydroxyacetone, glycerol, pyruvaldehyde, glyceraldehyde and succinate) are shown to be negligible under normal process conditions. Results on various samples agreed well with those obtained by flow injection methods based on enzymatic spectrometry (Olsson et al., Anal. Chim. Acta, 1983, 145, 101) or catalytic calorimetry (Danielsson et al., Appl. Biochem. Bioeng., 1981, 3, 97).
Glycerol Hydrogen peroxide Interferences Process control Method comparison

"Measurement Of Biological Parameters During Fermentation Processes"
Anal. Chim. Acta 1984 Volume 163, Issue 1 Pages 111-118

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
T. Scheper, A. Gebauer, A. Sauerbrei, A. Niehoff and K. Schügerl

Abstract: Three techniques were tested. Firstly, the NADH-dependent fluorescence of micro-organisms was measured in batch and continuous cultures under aerobic and anaerobic conditions to provide information on the metabolic status of the cells. The effects of cell concentration. and of glucose, ethanol and O were studied. Secondly, various substrates were determined calorimetrically with an enzyme - thermistor device. Penicillin was determined selectively in a fermentation broth with use of immobilized penicillin amidase or penicillinase, and penicillin amidase activity was also measured. Thirdly, laser flow cytometry, with use of a commercial double-beam flow system, was used to determine the protein, DNA and RNA contents of single cells. The results obtained by this technique are discussed.
Penicillin Fermentation broth Immobilized enzyme

"Flow Sorption Calorimetry, A Powerful Tool To Investigate The Acid-base Character Of Organic Polymer Surfaces"
Fresenius J. Anal. Chem. 1997 Volume 358, Issue 1-2 Pages 244-247

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
S. Schneider A, F. Simon A, D. Pleul A, H.-J. Jacobasch

Abstract: Flow sorption calorimetry (FSC) can be a useful tool to estimate the Lewis acid-base behavior of the surface of organic polymers with less than 1 m2/g surface area. Polyethylene powders grafted with different amounts of acrylic acid have been chosen as samples. The surface of the powders was investigated by means of X-ray photoelectron spectroscopy (XPS) at first and than brought into contact with the strong electron donor triethylamine in a special FSC measuring system. The heat of the displacement isotherm together with the surface excess isotherm of triethylamine adsorbed onto the powders was determined. The results obtained with FSC and XPS were well correlated and gave a comprehensive picture of the acidic surface character of modified polyethylene.
Acids Bases Polymers

"A Flow Microcalorimetric Method For Enzyme Activity Measurements: Application To Dihydrofolate Reductase"
Anal. Biochem. 1987 Volume 165, Issue 2 Pages 341-348

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Lucas Sica, Robert Gilli, Claudette Briand and Jean Claude Sari*

Abstract: A flow microcalorimetric method was developed for the analysis of enzymatic activities in crude tissue homogenates. It can be applied whenever a heat exchange is involved in an enzymatic reaction. The consequent sensitivity obviously depends on the enthalpy variation observed. Dihydrofolate reductase was chosen as an example; this enzyme is the molecular target of methotrexate, a widely used anticancer agent. This calorimetric method, whose sensitivity limit is 1.48 x 10^-4 units of dihydrofolate reductase per milliliter of reactant medium, allows enzyme activity measurements in tissues with low dihydrofolate reductase levels. A few examples of measurements in animal tissues are given. These measurements are of some interest; indeed, increased activity and increased levels of this enzyme are two of the mechanisms which may explain resistance to methotrexate.
Enzyme, dihydrofolate reductase

"Flow Microcalorimetric Determination Of Cellobiase Activity And Its Inhibition By Glucose"
Anal. Lett. 1993 Volume 26, Issue 10 Pages 2107-2112

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Beran, M.;Paulicek, V.

Abstract: An assay is described for cellobiase (β-glucosidase) activity of the Trichoderma reesei CCF 1853 cellulase complex. Analysis was performed using a flow-mix system coupled with a free standing multichannel microcalorimeter. Sample solution was merged with a stream of 5 mM citrate buffer solution of pH 5 in the flow-mix cell, before passing through the measuring cell. Once a stable baseline was obtained , the clean buffer solution was changed step by step for solution with different concentrations of cellobiose or cellobiose and glucose. The heat generated by the enzymatic reaction and other side reactions was recorded in the measuring cell and the signal was corrected by the subtraction of the individual dilution heat flows of cellobiose and glucose, the interaction heat flows of cellobiose and glucose and the interaction heat flows of glucose and sample solution The flow rate was 55 mL/h and the residence time was 40 s. The method allowed the determination of cellobiase activity or cellobiose concentration with a detection limit of 10 µM-cellobiose. Results are discussed.
Enzyme, β-glucosidase

"Fast Determination Of Whole Blood Glucose With A Calorimetric Micro-biosensor"
Sens. Actuat. B 1993 Volume 15, Issue 1-3 Pages 141-144

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Bin Xie, Ulrika Hedberg, Michael Mecklenburg and Bengt Danielsson

Abstract: A calorimetric flow injection sensor was used to provide rapid determination of whole-blood glucose without pre-treatment. Glucose oxidase was immobilized together with catalase on controlled-pore glass beads in a micro-column (1.5 cm x 0.6 mm i.d.). When the sample was reduced in volume from 20 to 1 µL the linear range for glucose was increased from 0.5-2.5 mM to 0.5-20 mM. Results correlated well with those obtained with a Reflolux-S blood glucose analyzer.. The RSD (n = 100) was 3.7%. The sensor could be used for at least one month if stored at 4°C. The measurement period was 40 s and the device could be used to analyze 90 samples per hour.
Glucose Whole Controlled pore glass

"Analytical Application Of Immobilized Acid Urease For Urea In Flow Streams"
Sens. Actuat. B 1991 Volume 5, Issue 1-4 Pages 241-243

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Ikuo Satoh* and Masashi Akahane, Kunio Matsumoto

Abstract: A description is given of a system for the calorimetric flow injection determination of urea (I) which is based on acid urease immobilized on porous glass beads packed into a small polymer column. For determination of I, sample is introduced at 1 mL min-1 via a citrate buffer carrier stream (0.1M; pH 5) and the heat generated by the enzymatic hydrolysis of I is monitored through the enzyme thermistor system. The calibration graph was rectilinear from 0.05 to 2 mM I (1 mL samples). Analysis time was 6 min and the coefficient of variation for 1.0 mM I was 1%. The method may be applied to the determination of I in alcoholic beverages.
Urea Buffer Column Immobilized enzyme Porous glass beads

"Calorimetric Flow Injection Determination Of Glutathione With Enzyme - Thermistor Detector"
Sens. Actuat. B 1991 Volume 5, Issue 1-4 Pages 245-247

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Ikuo Satoh*, Shuji Arakawa and Akira Okamoto

Abstract: For the cited determination glutathione sulfhydryl oxidase and catalase were immobilized separately with bovine serum albumin on Eupergit-C (100 to 200 µm) and double layered into a small polymer column. Sample solution was introduced at 1 mL min-1 via McIlvain buffer (pH 5.0) and the heat generated was measured by the enzyme - thermistor device. The calibration graph was rectilinear from 0.5 to 10 mM glutathione. Analysis time was 6 min and the coefficient of variation for 5.0 mM glutathione was 1.2% (n = 5).
Glutathione Buffer Column Detector Immobilized enzyme

"Spectroscopic, Calorimetric, And Kinetic Demonstration Of Conformational Adaptation In Peptide-antibody Recognition"
Biochemistry 1995 Volume 34, Issue 50 Pages 16509-16518

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Lukas Leder, Christine Berger, Susanne Bornhauser, Hans Wendt, Friederike Ackermann, Ilian Jelesarov, and Hans Rudolf Bosshard

Abstract: Little is known about the extent to which protein flexibility contributes to antigen-antibody recognition and cross-reactivity. Using short coil peptides (leucine zippers) as model antigens, we demonstrate that a monoclonal antibody can force a noncognate peptide into a conformation that is similar to the conformation of the cognate peptide against which the monoclonal antibody is directed. Monoclonal antibodies 29AB and 13AD were raised against the 29-residue peptide LZ (Ac-EYEALEKKLAALEAKLQALEKKLEALEHG-amide) that forms a very stable coiled coil. The two antibodies cross-reacted strongly with the random coil analogue LZ(7P14P) that contains Lys-->Pro and Ala-->Pro substitutions in positions 7 and 14, respectively. The antibody-bound peptide LZ(7P14P) adopted an altered conformation that possibly was coiled coil-like, as shown by CD difference spectroscopy and fluorescence quenching experiments on coumarin-labeled peptides. Isothermal titration calorimetry revealed that the cross-reaction of antibodies 13AD and 29AB with the random coil peptide LZ(7P14P) exhibited a large unfavorable entropy. This, however, was strongly compensated by a more favorable enthalpy, resulting in only a small difference between the association constants for peptide LZ and LZ(7P14P), respectively. To investigate the opposite type of cross- reaction, monoclonal antibody 42PF was raised against the random coil peptide LZ(7P14P). 42PF cross-reacted with coiled coil peptide LZ by forcing it to dissociate into single chains. Enthalpy/entropy compensation again enabled the cross-reaction, which now was entropically favored and enthalpically disfavored. The rate of reaction of antibody 42PF with peptide LZ was controlled by the rate of dissociation of LZ into single chains. This observation, as well as the generally much slower reaction rate with the noncognate peptides, indicated that the cross-reactivity occurred because the antibody selected the conformer of the antigen that binds the strongest, a mechanism we call 'induced fit by conformational selection.' (FIA was used!)
Protein, structure Kinetic

"Flow Enthalpimetry"
Chem. Anal. 1985 Volume 79, Issue 1 Pages 97-135

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Schifreen, R.S.

Abstract: A review with 24 references. Historical development of instrumentation of flow enthalpimetry anal. is discussed. Design and construction of flow enthalpimeters, methodology, reactor models, dispersion, effects related to the measurement of temp., and reactor kinetics are also discussed. (SFS)

"Flow Injection Calorimetric Biosensing Of Cobalt(II) Ions"
Chem. Sens. 1991 Volume 7, Issue Suppl. A Pages 61-64

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]
Ikuo SATOH and Keiji WATANABE

Abstract: Alkaline phosphatase (I) apoenzyme was immobilized on oxiran - acrylic beads and packed into a column, which was then mounted in a thermistor probe. Tris - HCl buffer (0.1M, pH 8.0, containing 1 M NaCl) was pumped through the system at 1 mL min-1 and the sample solution was introduced by a rotary injection valve. The Co was determined in the range 0.04 to 1 mM by its partial re-activation of the I as assessed by injecting 0.1 mL of 0.1 M 4-nitrophenyl phosphate and measuring the temperature change, which was related to the concentration. of Co2+ applied to the column. The column was regenerated by using 40 mM pyridine-2,6-dicarboxylate (pH 6.0) as cofactor complexing agent.
Cobalt(II) Buffer Column Immobilized enzyme

"Fermentation Monitoring"
Curr. Opin. Biotechnol. 1991 Volume 2, Issue 1 Pages 17-22

Notice (8): Undefined variable: uid [APP/View/Elements/citation.ctp, line 40]