Document Detail

Refinement of the pressure assay for milk urea nitrogen.
MedLine Citation:
PMID:  11003237     Owner:  NLM     Status:  MEDLINE    
We report improvements in the application of a pressure-based assay for urea. The assay involved the enzymatic hydrolysis of urea and subsequent measurement of CO2 partial pressure. Effects of the preservative bronopol on the assay and their implications for laboratory applications are discussed. A method of remediating these effects with cysteine is described. A method is also described wherein these additives can be used to prepare standards of known urea concentration in milk. The improved assay can be used to measure urea N in unadulterated milk or in bronopol preserved milk with an accuracy of +/-0.7 mg/dl (0.25 mM) in the range from 0 to 30 mg/dl (0 to 10.7 mM).
D M Jenkins; M J Delwiche; E J DePeters; R H BonDurant
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of dairy science     Volume:  83     ISSN:  0022-0302     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  2000 Sep 
Date Detail:
Created Date:  2001-01-03     Completed Date:  2001-09-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2042-8     Citation Subset:  IM    
Department of Biological and Agricultural Engineering, University of California at Davis, 95616, USA.
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MeSH Terms
Autoanalysis / veterinary
Biosensing Techniques
Carbon Dioxide / analysis*
Cysteine / administration & dosage
Glutamate Dehydrogenase / metabolism
Linear Models
Milk / chemistry*
Nitrogen / analysis*,  standards
Partial Pressure
Preservatives, Pharmaceutical / adverse effects
Propylene Glycols / adverse effects
Urea / analysis*,  standards
Urease / metabolism
Reg. No./Substance:
0/Preservatives, Pharmaceutical; 0/Propylene Glycols; 124-38-9/Carbon Dioxide; 52-51-7/bronopol; 52-90-4/Cysteine; 57-13-6/Urea; 7727-37-9/Nitrogen; EC Dehydrogenase; EC

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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