ABSTRACT
A biosensor for the specific determination of uric acid in urine was developed using urate oxidase (EC 1.7.3.3) in combination with a dissolved oxygen probe. Urate oxidase was immobilized with gelatin by means of glutaraldehyde and fixed on a pretreated teflon membrane to serve as enzyme electrode. The electrode response was maximum when 50 mM glycine buffer was used at pH 9.2 and 35 degrees C. The enzyme electrode response depends linearly on uric acid concentration between 5-40 microM with a response time of 5 min. The enzyme electrode is stable for more than 2 weeks and during this period over 35 assays were performed.
Subject(s)
Biosensing Techniques , Uric Acid/urine , Humans , Oxygen , Urate OxidaseABSTRACT
A novel eggplant tissue homogenate-based membrane electrode with high selective response to catechol (5 x 10(-6)-2.5 x 10(-5) M concentration) has been constructed by immobilizing tissue of eggplant (Solanum melangena L.) at dissolved oxygen probe. In order to optimize the stability of the electrode, general immobilization techniques are used to secure the eggplant tissue section physically in a gelatin-glutaraldehyde cross-linking matrix. The electrode response was maximum when 50 mM phosphate buffer was used at pH 7.0 and 35 degrees C. The sensor is stable for more than 3 months.
Subject(s)
Biosensing Techniques , Catechols/analysis , Buffers , Hydrogen-Ion Concentration , Solanaceae , TemperatureABSTRACT
A biosensor for the specific determination of hydrogen peroxide was developed using catalase (EC 1.11.1.6) in combination with a dissolved oxygen probe. Catalase was immobilized with gelatin by means of glutaraldehyde and fixed on a pretreated teflon membrane served as enzyme electrode. The electrode response was maximum when 50 mM phosphate buffer was used at pH 7.0 and at 35 degrees C. The biosensor response depends linearly on hydrogen peroxide concentration between 1.0x10(-5) and 3.0x10(-3) M with a response time of 30 s. The sensor is stable for >3 months so in this period >400 assays can be performed.
ABSTRACT
An enzyme electrode for the specific determination of catechol was developed by using catechol oxidase (EC 1.10.3.1) from eggplant (Solanum melangena L.) in combination with a dissolved oxygen probe. Optimization studies of the prepared catechol oxidase enzyme electrode established a phosphate buffer 50 mM at pH 7.0 and 35°C to provide the optimum conditions for affirmative electrode response. The enzyme electrode response depended linearly on a catechol concentration range of 5â¢10(-7)-30â¢10(-5) M with a response time of 25 sec and substrate specificity of the catechol oxidase electrode of 100%. The biosensor retained its enzyme activity for at least 70 days.
