Amperometric l-lactate-sensing electrode based on a polyion complex layer containing lactate oxidase. Application to serum and milk samples

• Published in: Analytica chimica acta Vol. 314; no. 3; pp. 233 - 239
• Main Authors: Mizutani, Fumio, Yabuki, Soichi, Hirata, Yoshiki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 20.10.1995; Elsevier
• Subjects: Amperometry; Chemistry; Electrochemistry; Electrodes: preparations and properties; Enzymatic methods; Exact sciences and technology; General and physical chemistry; Ion selective electrodes; l-Lactic acid; Permselective membranes; Polyion complex; Amperometry; Enzymatic methods; l-Lactic acid; Permselective membranes; Polyion complex; Lactate 2-monooxygenase; Enzyme; Experimental study; Carbon; Enzyme electrode; Ion selective electrode; Electrodes; Ion exchange membrane; Styrenesulfonate copolymer; Biosensor; Detection limit; Selective permeability; Serum; Polyion; Oxidoreductases; Lactic acid; Lysine copolymer; Glassy state; Milk; Modified material
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/0003-2670(95)00278-8

An amperometric enzyme electrode for l-lactic acid was prepared by immobilizing lactate oxidase (LOD) in a polyion complex membrane. An aqueous solution containing poly- l-lysine and LOD was placed on a glassy carbon electrode, and an aqueous solution of poly(4-styrenesulfonate) was added to the polycation/LOD mixture and dried. The anodic current (at 1 V vs. Ag AgCl ) of this enzyme electrode increased immediately after the addition of L-lactic acid and the response time was < 5 s. A linear response to l-lactic acid was observed up to 0.3 mM with a detection limit of 0.1 μM. The enzyme electrode was applied to the determination of l-lactic acid in sera and sour milk: the polyion complex membrane showed permselectivity based on the solute size with the molecular weight cut-off of ca. 100, which was very effective in suppressing the electrochemical interference by l-ascorbic acid, uric acid and acetaminophen. The electrode could be used for at least two months.