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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Electrochemistry

  • Publisher:
  • FAD Code: ELEC
  • CODEN: EECTFA
  • ISSN: 1344-3542
  • Abbreviation: Electrochemistry
  • DOI Prefix: 10.5796/electrochemistry
  • Other Name(s): Denki Kagaku oyobi Kogyo Butsurikagaku, Journal of the Electrochemical Society of Japan, Denki Kagaku
  • Language: English
  • Comments: Fulltext from 1999 V67

Citations 5

"Calorimetric Determination Of Zinc(II) Ions Based On An Apoenzyme Reactivation Method With A Thermolysin Column"
Electrochemistry 2003 Volume 71, Issue 6 Pages 453-456
Yasuhiro IIDA, Chiaki GONOKAMI, Taichi MORII, and Ikuo SATOH

Abstract: A calorimetric flow-injection analysis (FIA) with an immobilized thermolysin column was applied to determination of zinc (II) ions based on the apoenzyme reactivation method. The immobilization yield and the enzyme stability were significantly improved by using NaBr solution for dissolving thermolysin. The catalytic activity of the enzyme-packed column was assessed by injecting 1.0 mL of synthetic oligopeptide solution as a substrate into the system. The column was regenerated on exposure to 100 mM EDTA solution and reversibly reactivated with addition of zinc(II) ions. The reactivation ratio depended on the concentration of zinc (II) ions solution injected. Thus, reactivation ratio was evaluated by injection of various concentrations of zinc(II) ions, and thereby, zinc(II) ions were determined. The zinc(II) ions in a range of 10 to 100 ?M were measured.

"Novel Detection System For Calcium(II) Ions Based On An Apoenzyme Reactivation Method Using An Amylase Column As A Recognition Element"
Electrochemistry 2003 Volume 71, Issue 6 Pages 449-452
Yasuhiro IIDA, Yumiko SATO, and Ikuo SATOH*

Abstract: A flow-injection amperometric system for evaluation of the activity of an immobilized ?-amylase column was constructed and the system was applied to detect of calcium (II) ions based on the apoenzyme reactivation method. The ?-amylase activity was amperometrically evaluated by using a double-layered column which consisted of ?-glucosidase and pyranose oxidase. The detection of calcium (II) ions, being the cofactor of ?-amylase, was realized by measuring the reactivation of apo-type ?-amylase column, which was the recognition element of Ca(II) ions. Maleate buffer (0.1 M, pH 6.0) as a carrier solution was continuously pumped through the system, and sample solutions were introduced into the system via rotary injection valves. The catalytic activity of the multi-enzyme column was assessed by injecting 0.5% starch solution as a substrate. Calcium(II) ions in 1.0 mM levels were detected by using the system based on the apoenzyme reactivation method.

"Application Of An Electrolytic Device To An FIA System For Extension Of The Determination Range Of L-ascorbic Acid"
Electrochemistry 2002 Volume 70, Issue 7 Pages 515-517
Yasuhiro IIDA, Takuto SATOH, Ikuo SATOH

Abstract: The flow injection amperometric determination of L-ascorbic acid with a laccase column was investigated. Laccase (EC 1. 10. 3. 1.) covalently immobilized onto porous glass beads was used as a recognition element for L-ascorbic acid. The immobilized enzymes were packed into a small polymer column, and then mounted in a water-jacketed holder. The biosensing system was assembled with the column unit and a flow-through type of an oxygen electrode for monitoring dissolved oxygen enzymatically consumed. L-Ascorbic acid was amperometrically determined in a range of 0. 05-1.0 mM. In order to increase the amount of dissolved oxygen in the carrier stream, an electrolytic device was applied to the FIA system. Then, we could expand the linear range of the L-ascorbic acid determination from 0.05 to 2.0 mM by using the electrolytic device.

"Construction And Characterization Of Glucose Enzyme Sensor Employing Engineered Water Soluble PQQ Glucose Dehydrogenase With Improved Thermal Stability"
Electrochemistry 2000 Volume 68, Issue 11 Pages 907-911
Yuka TAKAHASHI, Satoshi IGARASHI, Yukie NAKAZAWA, Wakako TSUGAWA, Koji SODE

Abstract: In this study, we constructed glucose enzyme sensors with increased thermal stability employing engineered PQQGDH-B. First, we demonstrated the enzyme glucose sensor employing an engineered PQQGDH-B, Ser231Lys. The residual activity after heat treatment at 60°C for 2 hours of the enzyme electrode employed Ser231Lys was 80% of the initial activity, whereas the electrode employed native PQQGDH-B was 30%. Second, we investigated the effect of cross-linking chemical modification on the thermal stability of PQQGDH-B. The cross-linked PQQGDH-B had high thermal stability and the half life time at 55°C was 63 min whereas that of native enzyme was 4 min. Furthermore, we demonstrated the Flow Injection Analysis (FIA) system for glucose measurement employed the cross-linked PQQGDH-B. The high operational stability of this system showed the very stable responses (SD was within 3%) for Ino times of glucose injection.

"Preparation Of A Glucose-sensing Electrode Based On Glucose Oxidase-attached Polyion Complex Membrane Containing Microperoxidase And Ferrocene"
Electrochemistry 2000 Volume 68, Issue 11 Pages 853-855
Soichi YABUKI, Fumio MIZUTANI, Yoshiki HIRATA

Abstract: A glucose oxidase-attached polyion complex membrane containing microperoxidase and ferrocene was formed on a carbon electrode. The enzyme electrode gave a reductive current response (100% response time, within 20 s), and steady-state response was proportional to the glucose concentration up to 0.2 mM. Lower detection limit was 1 µ-M The current response decreased gradually, owing to the loss of the microperoxidase activity. The enzyme electrode was used for the detection of glucose concentration in beverages. The results obtained agreed well with those obtained by Boehringer F-kit method. The electrode would be useful as a glucose biosensor for real samples.
Glucose Polymer