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Determination of catalase‐like activity in plants based on the amperometric monitoring of hydrogen peroxide consumption using a carbon paste electrode modied with ruthenium(IV) oxide
Author(s) -
Dousikou Melpomeni F.,
Koupparis Michael A.,
Efstathiou Constantinos E.
Publication year - 2006
Publication title -
phytochemical analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 72
eISSN - 1099-1565
pISSN - 0958-0344
DOI - 10.1002/pca.910
Subject(s) - chemistry , hydrogen peroxide , amperometry , ascorbic acid , detection limit , catalase , inorganic chemistry , electrode , ruthenium , selectivity , oxide , ruthenium oxide , nuclear chemistry , electrochemistry , catalysis , chromatography , organic chemistry , antioxidant , food science
Abstract A carbon paste electrode containing ruthenium(IV) oxide as a modier was tested as an effective hydrogen peroxide amperometric sensor in bulk measurements (hydrodynamic amperometry). Factors that influence its overall analytical performance, such as pH and the applied potential, were examined. The RuO 2 ‐modied electrode displayed high sensitivity towards hydrogen peroxide, with detection limits as low as 0.02 m m at pH 7.4 and 0.007 m m at pH 9.0. The method was applied for monitoring the decomposition of hydrogen peroxide (by catalase) in phosphate buffer of pH 7.4. The relative response of the electrode towards ascorbic acid was assessed and it was found that the selectivity of the RuO 2 ‐modied electrode towards hydrogen peroxide over ascorbic acid could be signicantly improved by electro‐polymerizing m ‐phenylenediamine on its surface prior to measurements. The RuO 2 ‐modied electrode was used for the kinetic (xed time) determination of catalase activity in the range of 4–40 U/mL (detection limit 1.2 U/mL). The method was applied to the determination of catalase‐like activity in various plant materials (recovery ranged from 93 to 101%, detection limit 480 U/100 g). Copyright © 2006 John Wiley & Sons, Ltd.