A specific enzyme electrode for spermine and spermidine

1983 ◽  
Vol 48 (2) ◽  
pp. 672-678 ◽  
Author(s):  
Lumír Macholán ◽  
Dagmar Jílková
Keyword(s):  
Hydrogen Peroxide ◽  
Polyamine Oxidase ◽  
Enzyme Electrode ◽  
Urine Samples ◽  
Optimum Conditions ◽  
Specific Enzyme

A sensor method has been worked out for the determination of spermine and spermidine in concentrations 0.02-0.5 mmol l-1. The method is based on amperometric measurement of the consumption of oxygen and the formation of hydrogen peroxide in a reaction catalyzed by crosslinked polyamine oxidase from maize. One determination takes 1 to 2 min, with phosphate at least 8 months. The optimum conditions for the analysis are described and the applicability of the sensor to urine samples is dealt with.

Nonenzymatic stopped-flow fluorimetric method for direct determination of uric acid in serum and urine.

1989 ◽  
Vol 35 (2) ◽  
pp. 230-233 ◽  
Author(s):  
D Pérez-Bendito ◽  
A Gómez-Hens ◽  
M C Gutiérrez ◽  
S Antón
Keyword(s):  
Hydrogen Peroxide ◽  
Uric Acid ◽  
Direct Determination ◽  
Urine Samples ◽  
Stopped Flow ◽  
Fluorimetric Determination ◽  
Kinetic Measurements ◽  
Serum And Urine ◽  
Serum And Urine Samples

Abstract A simple, direct, sensitive, and selective stopped-flow method for the fluorimetric determination of uric acid in serum and urine samples is described. The variation of fluorescence intensity during the reaction between uric acid and 1,1,3-tricyano-2-amino-1-propene (triap) in the presence of hydrogen peroxide is monitored. For these kinetic measurements peroxide is monitored. For these kinetic measurements we used a versatile stopped-flow module that can be fitted to any fluorimeter. The linear range of the proposed method is 0.08-3.00 mg of uric acid per liter, and the detection limit is 0.03 mg/L. Within- and between-assay CVs and selectivity data are reported. Results for serum and urine samples correlated well with those obtained by the uricase method The proposed method is inexpensive and requires no sophisticated detection equipment.

scholarly journals Determination of Oxalate in Urine, Using an Amperometric Biosensor with Oxalate Oxidase Immobilized on the Surface of a Chromium Hexacyanoferrate-Modified Graphite Electrode

2000 ◽  
Vol 83 (5) ◽  
pp. 1212-1217 ◽  
Author(s):  
Stjepan Milardović ◽  
Zorana Grabarić ◽  
Mihael Tkalčec ◽  
Vlatko Rumenjak
Keyword(s):  
Hydrogen Peroxide ◽  
Oxalic Acid ◽  
Ethylenediaminetetraacetic Acid ◽  
Graphite Electrode ◽  
Oxalate Oxidase ◽  
Amperometric Biosensor ◽  
Urine Samples ◽  
Dialysis Membrane ◽  
Amperometric Method

Abstract A novel enzymatic amperometric method is described for the determination of oxalic acid in urine. An amperometric biosensor was made by immobilizing oxalate oxidase on the surface of a chromium(III) hexacyanoferrate-modified graphite electrode by using a bovine serum albumin and glutaraldehyde cross-linking procedure. The enzyme biocatalyzes oxalate decomposition in the presence of oxygen into carbon dioxide and hydrogen peroxide. The oxalate concentration, which is proportional to the amount of hydrogen peroxide, was determined amperometrically by measuring the current resulting in the reduction of hydrogen peroxide at a very low working potential (0.05 V versus the Hg | Hg2Cl2 | 3M KCl electrode), which minimized the influence of the possible interferences present in human urine. All experiments were performed with succinic buffer, pH 3.8, containing 0.1M KCl and 5.4mM ethylenediaminetetraacetic acid. In an aqueous solution of pure oxalic acid, the biosensor showed good linearity in a concentration range of 2.5–100μM without the use of a dialysis membrane. For untreated urine samples, a high correlation (R2 = 0.9949) was obtained between oxalate concentrations added to urine samples and oxalate recoveries calculated for determinations with the described oxalate biosensor.

Lysine specific enzyme electrode for determination of lysine in grains and foodstuffs

1978 ◽  
Vol 50 (11) ◽  
pp. 1481-1486 ◽  
Author(s):  
W. Claude. White ◽  
George G. Guilbault
Keyword(s):  
Enzyme Electrode ◽  
Specific Enzyme

Determination of Hydrogen Peroxide Residue in Food Using CdS Quantum Dots as Fluorescence Probes

2012 ◽  
Vol 455-456 ◽  
pp. 1189-1194 ◽  
Author(s):  
Yun Long Zeng ◽  
Ya Jing Wang ◽  
Zhong Hua Su ◽  
Chun Ran Tang
Keyword(s):  
Hydrogen Peroxide ◽  
Quantum Dots ◽  
Fluorescence Quenching ◽  
Fluorescence Probe ◽  
Influence Factors ◽  
Accurate Method ◽  
Fluorescence Probes ◽  
Cds Quantum Dots ◽  
Optimum Conditions

A simple and accurate method for determination of hydrogen peroxide (H2O2) using carboxymethyl cellulose coated CdS quantum dots (QDs) as a fluorescence probe was established. The influence factors of the fluorescence quenching system and the optimum conditions were investigated for analysis of hydrogen peroxide. It was found that the maximum relative fluorescence quenching intensity produced at pH 8.5 in 0.035 mol/L KH2PO4-Na2HPO4, when the concentration of CdS QDs was 1.9×10-3 mol/L and the reacting time and temperature were 45 minutes and 30°C, respectively. Under the optimum conditions, the relative fluorescence quenching intensity has a linear relationship with the logarithmic concentration of H2O2 in the range from 3×10-5 to 5×10-2 mol/L. The limit of the detection is 2.3×10-6 mol/L for H2O2. The method was used to determinate the amount of remained H2O2 in milk and Calcium Tablets successfully.

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