Enzyme electrode for the substrate urea

Abstract

The development of several types of a urea transducer suitable for rapid, continuous determination of urea is described. The transducer is called an enzyme electrode because it is made by placing a thin film of urease enzyme immobilized in acrylamide gel over the surface of a Beckman cationic electrode responsive to ammonium ions. The immobilized enzyme catalyzes the decomposition of urea to ammonium ion at the surface of the cat-

Synthesis of Polyaniline Based Nanocomposite Graphite Paste Electrode Modified with and Without Rice Husk for Sensor Application: A Comparative Study

“…The shoulder is appearing at 491 nm corresponds to the formation of ES (Emeraldine salt) phase irrespective of their organic supporting electrolyte. It shows very good resemblance with earlier reported work [7,8]. Fig.…”

“…Urea is an imperative analyte utilized as a part of blood and urine examination. Up to this point, numerous sorts of poten-tiometric urea sensors utilizing urease have been created [7][8][9][10][11]. The discovery standards of potentiometric urea sensors depend on the adjustments in pH and the convergence of smelling salts or carbon dioxide delivered amid urease responses.…”

Reliability of results of milk urea analysis by various methods using artificial milk control samples

“…A special problem is the preparation of milk urea standards for adequate calibration of different methods. This has been submitted to experiments and methodical examination, including the mutual result relationships of the methods, which are interpreted as potentially reference and other direct or indirect ones (for example filter MIR technology), frameworkly in the following fields: -the preparation of calibration standards for different methods of MUC determination, potentially for urea determination in other body fluids (Wolfschoon-Pombo et al, 1981;Oltner et al, 1985;Hanuš et al, 1995Hanuš et al, , 1997; -the examination, development, construction and validation of enzymatic sensors, reactors, and potentially biosensors for the analysis of urea concentration in different biological materials, especially in milk (Guilbault and Montalvo, 1970;Sundaram, 1979;Thavarungkul et al, 1991;Sansubrino and Mascini, 1994;Koncki et al, 1995;Ciana and Caputo, 1996;Sheppard et al, 1996); -the validation of the relationships of recently developed principles and methods of MUC determination or urea determination in blood to the current methods or to potentially reference ones, mostly specific ureolytical ones (Broutin, 2000); -a notice of problems of recovery and reliability of urea determination under the conditions of mid filter transmission infrared technology (MIR) in comparison with validated methods, where the determination coefficient of accuracy was about 50% (Here, 1998). The aim of this study was to evaluate the relationships between the currently used principles of methods of MUC determination in the Czech Republic, especially of new modern methods (measurement in the main area of infrared spectrum with use of Fourier transformations, FT-MIR; Lefier et al, 1996), on artificially constructed control samples on the milk basis and to deduce the relevant methodical recommendations for enhancement of reliability and improvement of practical interpretation of produced analytical results due to obtained theoretical relationships.…”

Biosensors in food processing

“…In the year 1970, Guilbault and Montalvo described the first potentiometric enzyme electrode. It was a urea-sensor based on enzyme urease immobilized at an ammonium (NH4 + ) selective liquid membrane electrode (Guilbault and Montalvo 1970). In the year 1973, Guilbault and Lubrano described glucose and a lactate enzyme sensor based on hydrogen peroxide detection at a platinum electrode (Guilbault and Lubrano 1973).…”