Biomaterial Database

Fluorometric determination of urea by flow injection analysis. 1990

M S Abdel-Latif, and G G Guilbault

Department of Chemistry, University of New Orleans, Louisiana 70148.

Urea was determined using fluorometry with flow injection analysis. O-phthalaldehyde (OPA) reacts with enzymatically generated ammonia and sulfite in alkaline medium to give a highly fluorescent compound that has an excitation wavelength of 372 nm and an emission wavelength of about 430 nm. The method is more selective to ammonia than the one which uses mercaptoethanol in place of the sulfite. Urease was immobilized to a Pall Immunodyne membrane which is commercially available. The immobilization occurs through covalent bonding which results in a highly stable enzyme preparation. The enzymatic membrane was fitted in a 5 cm long, 0.125 inch o.d. Teflon tubing which served as the enzymatic reactor. The system is difficult to use for the analysis of urea in serum because some compounds normally present in serum fluoresce at the same wavelength. This results in higher values for urea. If the reaction system is to be used for the evaluation of urea in serum, a blank should be run so that urea concentration can be calculated by difference.

UI	MeSH Term	Description	Entries
D008722	Methods	A series of steps taken in order to conduct research.	Techniques,Methodological Studies,Methodological Study,Procedures,Studies, Methodological,Study, Methodological,Method,Procedure,Technique
D009764	o-Phthalaldehyde	A reagent that forms fluorescent conjugation products with primary amines. It is used for the detection of many biogenic amines, peptides, and proteins in nanogram quantities in body fluids.	ortho-Phthalaldehyde,Orthophthaldialdehyde,o-Phthaldialdehyde,ortho-Phthalic Aldehyde,Aldehyde, ortho-Phthalic,o Phthalaldehyde,o Phthaldialdehyde,ortho Phthalaldehyde,ortho Phthalic Aldehyde
D002138	Calibration	Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.	Calibrations
D004800	Enzymes, Immobilized	Enzymes which are immobilized on or in a variety of water-soluble or water-insoluble matrices with little or no loss of their catalytic activity. Since they can be reused continuously, immobilized enzymes have found wide application in the industrial, medical and research fields.	Immobilized Enzymes,Enzyme, Immobilized,Immobilized Enzyme
D005470	Fluorometry	An analytical method for detecting and measuring FLUORESCENCE in compounds or targets such as cells, proteins, or nucleotides, or targets previously labeled with FLUORESCENCE AGENTS.	Fluorimetry,Fluorometric Analysis,Analysis, Fluorometric
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D013447	Sulfites	Inorganic salts of sulfurous acid.	Sulfite,Sulfites, Inorganic,Inorganic Sulfites
D014508	Urea	A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.	Basodexan,Carbamide,Carmol
D014510	Urease	An enzyme that catalyzes the conversion of urea and water to carbon dioxide and ammonia. EC 3.5.1.5.	Phytourease,Urea Amidohydrolase,Amidohydrolase, Urea