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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Friedrich Spener

Abbrev:
Spener, F.
Other Names:
Address:
Institut für Chemo- und Biosensorik, Mendelstr. 7, D-48149, Münster, Germany
Phone:
[49] 251 9802004
Fax:
[49] 251 9801911

Citations 4

"The Lipoxygenase Sensor, A New Approach In Essential Fatty Acid Determination In Foods"
Biosens. Bioelectron. 1997 Volume 12, Issue 11 Pages 1089-1099
Michael Schoemaker, Rainer Feldbrügge, Bernd Gründig and Friedrich Spener

Abstract: Both an enzyme electrode and enzyme column with immobilized lipoxygenase, respectively, were used for the determination of essential fatty acids. The former was applied in a batch system, the latter was part of a fully automated flow injection analysis (FIA)- system. The oxygen consumption due to the lipoxygenase catalyzed oxygenation of essential fatty acids was monitored amperometrically. Both systems were compared with regard to linear ranges of the calibration plots, sensitivities, detection limits, apparent Michaelis- Menten constants and lifetimes. The enzyme electrode showed different sensitivities for linoleic and α-linolenic acids, the most common essential fatty acids. The reason for this was not a second oxygenation step by lipoxygenase in case of α-linolenic acid, but a different dialytic behavior of the two substrates. Hence, only the FIA-system was used for the determination of these fatty acids in real matrices such as vegetable oils and margarines. In the presence of detergent the triglycerides of the hydrophobic food samples were converted into water soluble glycerol and free fatty acids by a 15 min incubation with a ready to use lipase/esterase-mix, thus avoiding the use of organic solvents for analysis. Results obtained by the enzymatic FIA-system were in excellent agreement with those obtained by standard gas chromatography.
Fatty acids, free Food Oil Amperometry Sensor Immobilized enzyme Method comparison

"Highly Sensitive Determination Of Hydrogen Peroxide And Peroxidase With Tetrathiafulvalene-based Electrodes And The Application In Immunosensing"
Biosens. Bioelectron. 1997 Volume 12, Issue 1 Pages 43-52
Frank Wendzinski, Bernd Gründig, Reinhard Renneberg and Friedrich Spener*

Abstract: A tetrathiafulvalene modified graphite electrode coupled with horseradish peroxidase is described, capable of monitoring H2O2 by FIA with a detection limit of 7 nM at a potential of +20 mV vs. a SCE. Holding the H2O2 constant, the detection limit of horseradish peroxidase was 150 pM. The system was evaluated and applied to the determination of 5-100 ng/ml of rabbit IgG as a model analyte by sandwich immunoassay.
Hydrogen peroxide Enzyme, horseradish peroxidase Immunoglobulin G, mouse Biological Immunoassay Electrode Electrode

"Comparison Of Different Types Of Immunoaffinity Reactors In An Electrochemical Flow Injection Immunoanalysis System Developed For Residue Analysis"
Biocatal. Biotransform. 1999 Volume 17, Issue 2 Pages 103-124
U.J. Meyer, D. Trau, G. Key, M. Meusel and F. Spener

Abstract: A comparison of different types of immunoreactors for a flow injection immunoanalysis (FIIA) system is presented. The use of the FIIA system was demonstrated here with the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The hardware system centers around the immunoreactor. In the preferred reactor set-up, a column is filled with protein G-coated porous beads serving as the affinity matrix for the antibody. In the 2,4-D assay a 2,4-D-alkaline phosphatase conjugate competes with the analyte in the sample for binding to the anti-2,4-D antibody. Subsequently p-aminophenol, generated from the enzymatic reaction with p-aminophenyl phosphate, is detected at±150 mV at a carbon working electrode versus Ag/AgCl. The immunoreactor allows for more than 150 measurements. The fully automated assay procedure needs 15 min only for one measurement. For 2,4-D the working range for the determination in water samples was between 1 and 1000 µg/L. Results obtained with the packed column reactor are compared to glassy capillary reactors and miniaturized silicon chip reactors used in previous studies.

"Amperometric Immunosensor For The Detection Of 2,4-dichlorophenoxyacetic Acid (2,4-D) In Water"
Anal. Lett. 1997 Volume 30, Issue 3 Pages 515-525
M. Wilmer; D. Trau; R. Renneberg; F. Spener

Abstract: An amperometric immunosensor for the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in water has been developed using sequential injection analysis techniques. The system is based on a rapid competitive enzyme immunoassay employing an alkaline phosphatase-labeled monoclonal antibody directed against the herbicide and an immunoreactor with 2,4-D immobilized via bovine serum albumin either to Eupergit in a column or directly to the surface of a glass capillary. The detection limit of the immunosensor at 0.1 µg 2,4-D/L without enrichment of the analyte makes automatic measurements of 2,4-D in drinking and groundwater feasible.
2,4-dichlorophenoxyacetic acid Endothall sodium Water Ground Amperometry Sequential injection