title: A novel amperometric biosensor based on a co-crosslinked L-lysine-α-oxidase/overoxidized polypyrrole bilayer for the highly selective determination of L-lysine.
abstract: An amperometric biosensor for the determination of L-lysine based on L-lysine-α-oxidase immobilized by co-crosslinking on a platinum electrode previously modified by an overoxidized polypyrrole film is described. The optimization of experimental parameters, such as pH and flow rate, permitted to minimize significantly substrate interferences even using a low specific, commercial enzyme. The relevant biases introduced in the measurement of lysine were just about 1% for L-arginine, L-histidine and L-ornithine, roughly 4% for L-phenylalanine and L-tyrosine. The developed approach allowed linear lysine responses from 0.02 mM up to 2 mM with a sensitivity of 41 nA/(mM × mm(2)) and a detection limit of 4 μM (S/N=3). No appreciable loss in lysine sensitivity was observed up to about 40 days. Allowing polypyrrole layer to remove interference from electroactive compounds, the present method revealed suitable to detect L-lysine in a pharmaceutical and cheese sample, showing a good agreement with the expected values.
authors.affiliation: Dipartimento di Scienze, Università della Basilicata, Potenza, Italy. antonio.guerrieri@unibas.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Guerrieri
authors.forename: Rosanna
authors.initials: R
authors.lastname: Ciriello
authors.forename: Tommaso R I
authors.initials: TR
authors.lastname: Cataldi
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000378:metabolism*; D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000032:analysis*; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D011758:Pyrroles / Q000737:chemistry / Q000378:metabolism*
chemical_list: D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D000594:Amino Acid Oxidoreductases; C041123:L-lysine oxidase; D008239:Lysine
keywords: Biosensor; Flow injection analysis; Food analysis; L-lysine determination; L-lysine-α-oxidase; Overoxidized polypyrrole