EP0744466A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for the determination of lactic acid in organic materials of alimentary interest and biosensor for putting this method into effect
Assignee: CO RI AL SCpA
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Filing: 1996-05-10
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Granted: —
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Expires: 2016-05-10
Abstract
Abstract A method is described for the determination of lactic acid in organic materials of alimentary interest that involves reacting, in a buffered aqueous medium, a sample of the said materials, or a solution obtained by extracting them, with an enzyme system comprising L(+) lactate oxidase, D(-) lactate dehydrogenase and horseradish peroxidase and measuring the concentration of any oxygen produced as a result of the oxidation of the lactic acid contained in the said sample with an amperometric electrode that is selective for oxygen. A biosensor that can be used to put the above method into effect is also described.
Inventors
- 👤 Alfredo Azzoni
- 👤 Corrado Belicchi
- 👤 Barbara Cavalieri
- 👤 Franco Mazzei
- 👤 Claudio Botre'
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 19:32
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/001; C12Q1/005; Y; Y10; Y10S; Y10S435/00; Y10S435/817
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
104 words
Method for the simultaneous determination of D(-) and L(+) lactic acid in organic materials of alimentary interest, comprising the following stages: - reacting, in a buffered aqueous medium, a sample of the said materials, or a solution obtained by extracting these materials with solvent, with an enzyme system comprising L(+)lactate oxidase (LOD), D(-) lactate dehydrogenase (D-LDH) and horseradish peroxidase (HPO), in the presence of NAD and Mn ++ , - measuring the concentration of any oxygen formed as a result of the oxidation of the lactic acid contained in the sample or the solution with the aid of an amperometric electrode selective for oxygen.
Claim 2
Dependent Claim
22 words
Method according to Claim 1, characterized in that the enzymes LOD, D-LDH and HPO are immobilized on at least one suitable support.
Claim 3
Dependent Claim
20 words
Method according to Claim 2, characterized in that the said enzymes are immobilized on a single support comprising a membrane.
Claim 4
Dependent Claim
52 words
Method according to Claim 3, characterized in that the amperometric electrode used for measurement is separated from the buffered aqueous medium by a first, gas-permeable membrane that is in direct contact with the electrode and in that a second membrane bearing the above immobilized enzymes is placed externally over this first membrane.
Claim 5
Dependent Claim
24 words
Method according to Claim 4, characterized in that a further membrane, consisting of a dialysis membrane, is placed externally over the said second membrane.
Claim 6
Dependent Claim
25 words
Method according to Claim 5, characterized in that the said second membrane is a membrane made of nylon 6,6 bearing carboxyl groups on its surface.
Claim 7
Dependent Claim
88 words
Method according to any of the above Claims, characterized in that the amperometric electrode consists of a platinum wire electrode (2) coated with a layer (2a) of an epoxy resin, which separates and insulates it from a reference electrode (3) (Ag/AgCl) arranged coaxially around it, the two electrodes (2) and (3) being fixed inside a cylindrical container (4) filled with an electrolyte solution or an electrolyte gel with a suitable coating (3a) interposed, and in that the said platinum electrode (2) acts as an indicator for the oxygen.
Claim 8
Dependent Claim
28 words
Method according to Claim 7, characterized in that the said platinum electrode (2) is kept at a potential of approximately -650 mV compared with the reference electrode (3).
Claim 9
Dependent Claim
57 words
Method according to Claim 8, characterized in that the amperometric electrode is separated from the buffered aqueous medium by a first membrane made of Teflon, over which are placed externally a second membrane consisting of the said membrane made of nylon 6,6 bearing immobilized LOD, D-LDH and HPO and a third membrane consisting of a dialysis membrane.
Claim 10
Dependent Claim
83 words
Biosensor (B) for the simultaneous determination of D(-) and L(+) lactic acid in organic materials of alimentary interest comprising a sensor (1) for oxygen, including a membrane (6) made of Teflon that is permeable to oxygen, characterized in that over the said membrane (6) are placed a membrane (7), on which are immobilized L(+) lactate oxidase (LOD), D(-) lactate dehydrogenase (D-LDH) and horseradish peroxidase (HPO), and a dialysis membrane (8), the said membranes being held firmly in place by an elastic ring (9).
Claim 11
Dependent Claim
18 words
Biosensor (B) according to Claim 10, characterized in that the said membrane (7) is made of nylon 6,6.
References Cited (Backward Citations)
No citation records indexed.
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