title: A colorimetric assay for amino nitrogen in small volumes of blood: reaction with beta-naphthoquinone sulfonate.
abstract: An assay has been developed for the colorimetric estimation of total amino acids in small volumes (100 microliters) of whole blood. The procedure utilizes the reaction of amino nitrogen with beta-naphthoquinone sulfonate. It represents a substantial improvement on previously published methods by decreasing reagent volumes and accurately specifying and maintaining pH conditions for the reaction itself (9.2-9.4) and for removal of excess reagent prior to measurement of the resulting complex (2.2-2.4). Ammonia is the only compound shown to significantly interfere with the assay but this is not a problem at physiological concentrations.
authors.affiliation: Research Centre for Developmental Medicine and Biology, University of Auckland, New Zealand.
authors.forename: P C
authors.initials: PC
authors.lastname: Evans
authors.forename: F M
authors.initials: FM
authors.lastname: Ffolliott-Powell
authors.forename: J E
authors.initials: JE
authors.lastname: Harding
mesh_terms: D000596:Amino Acids / Q000097:blood*; D000641:Ammonia / Q000097:blood; D003124:Colorimetry / Q000379:methods* / Q000706:statistics & numerical data; D005069:Evaluation Studies as Topic; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009285:Naphthoquinones; D009584:Nitrogen / Q000097:blood*; D012680:Sensitivity and Specificity
chemical_list: D000596:Amino Acids; D009285:Naphthoquinones; D000641:Ammonia; D009584:Nitrogen