title: Flow injection analysis of serum urea using urease covalently immobilized on 2-fluoro-1-methylpyridinium salt-activated fractogel and fluorescence detection.
abstract: Serum samples were analyzed for their urea content using fluorescence flow injection analysis incorporating an immobilized urease bioreactor and a gas permeable separator. The urease was immobilized under mild and facile conditions to a hydrophilic 2-fluoro-1-methylpyridinium-activated support. The ammonia released as a result of urease-catalyzed urea hydrolysis diffused through a gas permeable membrane into a constant stream of o-phthaldehyde solution to form a highly fluorescent product with lambda ex at 340 nm and lambda em at 455 nm. Up to 25 serum samples can be analyzed per hour. The within-day coefficient of variation (CV) was 1.12% and the day-to-day CV was 1.25% for serum containing 10.50 mg urea nitrogen dl-1. The bioreactor shows excellent storage (at 4 degrees C) and operational stabilities (at 37 degrees C).
authors.affiliation: Chemistry Department, University of the West Indies, St. Augustine, Trinidad.
authors.forename: D
authors.initials: D
authors.lastname: Narinesingh
authors.forename: R
authors.initials: R
authors.lastname: Mungal
authors.forename: T T
authors.initials: TT
authors.lastname: Ngo
mesh_terms: D000641:Ammonia / Q000378:metabolism; D002138:Calibration; D004800:Enzymes, Immobilized; D005453:Fluorescence; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010539:Permeability; D011726:Pyridinium Compounds; D013696:Temperature; D014508:Urea / Q000097:blood*; D014510:Urease / Q000378:metabolism*; D009764:o-Phthalaldehyde
chemical_list: D004800:Enzymes, Immobilized; D011726:Pyridinium Compounds; C066037:2-fluoro-1-methylpyridinium; D009764:o-Phthalaldehyde; D000641:Ammonia; D014508:Urea; D014510:Urease