TALANTA, 2000, VOL. 53, PP. 319-402

Construction of a L-lysine Biosensor by Immobilizing Lysine Oxidase on a Gold-Poly(o-Phenylenediamine) Electrode

Ioannis D. Karalemas^a, Constantinos A. Georgiou^b, Demetrius S. Papastathopoulos^a,*
^aLaboratory of Analytical Chemistry, Department of Chemistry, University of Athens, 157 71 Athens, Greece, and
^bChemistry Laboratory, Department of Sciences, Agricultural University of Athens, 75 Iera Odos, 118 55 Athens, Greece

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The construction of a L-lysine biosensor on a gold-strip electrode is described in this study. The construction comprises a) the formation of poly(o-phenylenediamine) membrane on the electrode surface via electropolymerization and b) the immobilization of lysine oxidase on the gold/poly(o-phenylenediamine) electrode with glutaraldehyde. The behaviour of  the gold/poly(o-phenylenediamine) electrode against H₂0₂ and lysine, as well as the repeatability of the electropolymerization and the time stability of the polymer were studied. The study showed that the electropolymerization procedure is repeatable, and that the polymer is quite stable for at least 40 days. The biosensor showed a linear calibration curve in the range of  (0.01-1) x 10^-5 M lysine. The interfering effect of  other aminoacids on the biosensor performance, was also studied and amperometric selectivity coefficients were calculated. The biosensor responded mainly against tyrosine and cysteine, while the response to phenylalanine, arginine, histidine and ornithine was very low. By changing the electropolymerization conditions, the effect of interferents was further reduced.

Keywords: lysine amperometric biosensor; lysine oxidase immobilization; o-phenylenediamine electropolymerization

*Corresponding author.
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Questions and comments to author: Dr C.A. Georgiou, cag@aua.gr
Phone: +3-0105294248, fax: +3010-5294265
Chemistry Laboratory, Agricultural University of Athens, Greece