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Kinetic studies on membraneless amperometric biosensors prepared from xanthine oxidase, organic conducting salt, and silicone oil
Author(s) -
Korell Ulrich,
Spichiger Ursula E.
Publication year - 1994
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140060407
Subject(s) - biosensor , amperometry , hypoxanthine , chemistry , detection limit , silicone oil , xanthine oxidase , nernst equation , immobilized enzyme , flow injection analysis , electrode , analytical chemistry (journal) , chromatography , inorganic chemistry , electrochemistry , organic chemistry , biochemistry , enzyme
Membrane‐free amperometric biosensors have been prepared from xanthine oxidase powder (XOD) (E.C.1.2.3.2) the organic conducting salt TF‐TCNQ, and silicone oil The sensor response to hypoxanthine can be described by the ezyme‐kinetic Michaelis‐Menten formalism with good correlation over a wide range of potential (–100 tc +300 mV vs Ag/AgCl) and pH (6.10 to 8.80)values. Measurements with rotating disk rotating disk electrodes reveal that XOD is oxidized by at least two transfer to the mediators so that the sensor can be operated in air‐saturated solution. Since open circuit conditions alter the kinetic parameters of the sensor, operation in flow analysis systems is recommended. Analytical features including response time (t 95 ≈ 10 seconds), detection limit (ca. 10 nM hypoxanthine), selective over interferents (e.g., ascirbate), and simplicity of preparation as well as operation and storage stability compare very favorably with other OXD biosensors.