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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Spectroscopy

Citations 2

"Reflectometric Interference Spectroscopy For The Determination Of Atrazine In Natural Water Samples"
Environ. Sci. Technol. 1996 Volume 30, Issue 6 Pages 1846-1851

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C. Mouvet, L. Amalric, S. Broussard, G. Lang, A. Brecht, and G. Gauglitz

Abstract: A reflectometric interference spectroscopy (RIFS; reflectance interferometry) system consisting of a halogen lamp, a flow cell and a diode array detector is described; diagram given. Water containing atrazine was mixed with PBS and K4E7 atrazine mAb and incubated for 5 min. The solution was injected into a FIA system which delivered the sample to the flow cell of the RIFS system for measurement of the optical thickness of a thin transparent film. The unoccupied antibodies bind to a atrazine modified transducer surface increasing the optical thickness; the lower the atrazine content the larger the number of unoccupied antibodies. The calibration graph was produced for 0.1-5 µg/l of atrazine with a detection limit of 0.35 µg/l. There was significant cross-reactivity from simazine and terbutylazine and humic acids interfered with the determination.
Atrazine Environmental Environmental Interferences Detector Flowcell

"Assessment Of Affinity Constants By Rapid Solid Phase Detection Of Equilibrium Binding In A Flow System"
J. Immunol. Methods 1997 Volume 201, Issue 2 Pages 189-206

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Jacob Piehler*, Andreas Brecht, Thomas Giersch, Bertold Hock and Günter Gauglitz

Abstract: We present a method for the determination of affinity constants based on equilibrium binding between an analyte and an antibody in liquid phase by a heterogeneous phase detection scheme. Equilibrium concentration of free antibody binding sites was probed kinetically by direct optical detection of specific binding to an immobilized analyte derivative. The additional binding signal due to dissociation of the analyte-antibody complex during detection was minimised by the use of fast flow-through conditions. The concentration of free antibody binding sites was titrated by adding increasing analyte concentrations. The affinity constant was derived from the titration curve by a non- linear least square fit of a model function. The affinity of monoclonal triazine antibodies to several s-triazine pesticides and a relevant metabolite was investigated. Kinetic determination of equilibrium concentration of free binding sites was carried out by reflectometric interference spectroscopy (RIfS) using flow injection analysis. The capabilities of the model were investigated using different analyte- antibody pairs and various antibody concentrations. Both bivalent IgG and monovalent Fab fragments were used to compare different binding models. The applied model corresponds well to the titration curves for affinity constants of 10(7) M-1 and higher. For lower affinity constants significant deviations due to dissociation of the analyte- antibody complex during detection were observed.
Antibodies Kinetic Immobilized analyte Complexation Interferences Solid phase detection