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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Non-immobilized enzyme

Classification: Reagent -> Non-immobilized enzyme

Citations 5

"Electrochemical Sensor Arrays"
Crit. Rev. Anal. Chem. 1999 Volume 29, Issue 2 Pages 133-153
Raluca-Ioana Stefan, Jacobus F. Van Staden and Hassan Y. Aboul-Enein

Abstract: The importance of sensor arrays in environmental, food and clinical analysis is discussed. The possible designs of sensor arrays is shown. The most reliable mathematical models for data processing are presented. The importance of different types of electrochemical sensor arrays in analytical chemistry as well as their performances are shown.
Environmental Food Biological Sensor Electrochemical analysis

"Determination Of Mercury(II) By Its Inhibitory Effect On The Enzymic Reaction Of Ethanol Oxidation Using Flow Injection"
Analyst 1992 Volume 117, Issue 5 Pages 921-924
M. Jesús Almendral Parra, Angel Alonso Mateos, Cándido Garcia de María and Leonor G. Rozas

Abstract: Samples were injected into a carrier stream of water and were merged with a solution of ethanol (500 ppm) in pyrophosphate buffer, pH 8.7, and then with a solution of alcohol dehydrogenase (0.2 mg mL-1) and nicotinamide adenine dinucleotide (0.48 mg mL-1) in the same buffer. The NADH produced by the conversion of ethanol into acetaldehyde was inhibited by Hg, which caused a reduction in the absorbance at 340 nm. The concentration. range was from 0.5 to 20 mg L-1 with a limit of detection of 0.5 mg l-1. The coefficient of variation (n = 10) for 5 ppm was between 1.1 and 1.4%. The results were in good agreement with those of the standard dithizone method.
Ethanol Spectrophotometry

"Microporous Membrane Flow Cell With Non-immobilized Enzyme For Chemiluminescent Determination Of Glucose"
Anal. Chem. 1982 Volume 54, Issue 11 Pages 1698-1701
David Pilosof and Timothy A. Nieman

Abstract: A microporous membrane separates a reagent reservoir, containing glucose oxidase buffered at pH 5, from the analyte flow stream containing glucose. The enzyme solution flows, under pressure, through the membrane at 3.5 pL/min. Lumlnol, KOH, and Cu(1,10-phen)32+ (1,10-phen = 1,l0-phenanthrollne) are added to the analyte 80 that the hydrogen peroxide produced by the enzymatic oxidation of glucose can be determined by chemiluminescence. The membrane allows creation of a pH gradient In the flow cell; the solution Is around pH 5 near the membrane where the enzymatic reaction occurs and Is strongly bask In the bulk of the analyte solution where the chemiluminescent reaction occurs. The membrane limits enzyme consumption to amounts that are miniscule in comparison to other glucose methods. The detection limit Is 5 x 10^-8 M. Precision Is 2-3% relative standard deviation (RSD). Serum samples were assayed (following deproteination); results correlate well with values obtained In a clinical laboratory using a Beckman Glucose Analyzer 2.
Glucose Biochemical analysis Chemiluminescence

"Development And Application Of Sample Injector For Flow Injection Analysis"
J. Flow Injection Anal. 1989 Volume 6, Issue 1 Pages 30-36
Wasako Tomoda, Kazuhide Uchida, Kyoko Saji, Kazuaki Fukushima and Shin-ichi Saito

Abstract: The constructed sample injector which has a quartet or synchronized six-valve system for flow injection analysis (diagram presented) has been utilized for assay of guanine deaminase (I). A 50 µL sample is injected and flows with a carrier stream of 0.05 M KH2PO4 - NaOH buffer of 7.4 containing 1.2% of Triton X-100 to react with an enzyme mixture consisting of xanthine oxidase, urate oxidase, catalase and peroxidase in the reaction coil (details given) before further reaction at pH 6.0 with 200 µL of substrate and color reagents of guanine, 3-methylbenzothiazolin-2-one hydrazone and N-ethyl-N-(3-sulfopropyl)-m-anisidine, followed by measurement at 570 nm. The calibration graph is rectilinear from 0.14 to 4.9 iu L-1 of I. For assay of 0.56 and 3.5 iu l-1, coefficient of variation are 1.9 and 0.8%, respectively.
Enzyme, guanine deaminase Spectrophotometry

"Selective Biocatalytic Measuring Cell For FIA Measurements"
Magy. Kem. Foly. 1992 Volume 98, Issue 5 Pages 201-205
Tarcali, J.;Nagy, G.;Pungor, E.

Abstract: A cylindrical polyacrylonitrile flow-through cell for FIA measurements has been developed which works by amperometrically detecting the H2O2 formed in enzyme-catalyzed reactions. The cell contains a biocatalytical working electrode that consists of a Pt wire covered by cellulose acetate film (permeable to H2O2, but impermeable to larger molecules) inside a thin, hollow dialysis fiber. The cell is filled with a solution of glucose oxidase or alcohol oxidase enzyme, buffer solution is pumped through the cell and the enzymatically produced H2O2 is detected; ethanol and glucose were used as model analytes. The calibration graph was rectilinear for 8 mM glucose and the system was stable for up to 50 injections of 50 µL portions of 1 mM glucose. A flow-through measuring cell developed for FIA measurements is described. The cell works by detecting amperometrically the hydrogen peroxide formed in enzyme catalyzed oxidation reactions of different substrates. The cell contains an easy to renew biocatalytic working electrode. The electrode consists of a thin, hollow dialysis fiber introduced into the flow anal. channel, an enzyme solution film applied to the fiber, and a thin platinum wire - based sensor electrode (coated with a cellulose acetate protective layer) housed inside the hollow fiber. The measuring cell was well suited for concentration. determination in small volumes of test solutions in the case of two different model compounds - glucose and ethanol.
Glucose Ethanol Amperometry Electrode Electrode