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Effect of HY‐zeolites on the performance of tyrosinase‐modified carbon paste electrodes
Author(s) -
MarkoVarga György,
Burestedt Elisabeth,
Svensson Carl Johan,
Emnéus Jenny,
Gorton Lo,
Ruzgas Tautgirdas,
Lutz Mareike,
Unger Klaus K.
Publication year - 1996
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.1140081209
Subject(s) - tyrosinase , catechol , carbon paste electrode , carbon fibers , chemistry , zeolite , biosensor , graphite , inorganic chemistry , catalysis , aqueous solution , electrode , redox , nuclear chemistry , chemical engineering , organic chemistry , materials science , composite number , electrochemistry , cyclic voltammetry , enzyme , composite material , biochemistry , engineering
The dependence of electrode response on additive properties in enzyme‐modified carbon paste was studied. Four different HY‐zeolite powders, dealuminated to different extents and characterized by both Si/Al ratio and hydrophilicity, were used as the carbon paste modifiers. The enzyme tyrosinase used in biosensors for the detection of catechol and other phenolic compounds was chosen as the model system for the construction of a composite carbon paste biosensor incorporating different HY‐zeolites as additives. Tyrosinase was trapped on the HY‐zeolite particles from a buffer solution, dried and mixed with graphite powder and a pasting oil. It was found that by incorporating HY‐zeolites into the carbon paste the heterogeneous reaction rate of catechol redox conversion and the signal response for catechol were increased. In the latter case a higher response was observed for increased hydrophilicity, i.e., decreased Si/Al ratio of the HY‐zeolite. The carbon paste/solution interface is considered to be an aqueous/organic phase and the characteristics of the enzyme‐ modified carbon paste electrode are related to theories, explaining enzymatic catalysis in organic solvents.