title: [A rapid computer-assisted method for the determination of urea in dairy products: skim milk powder from various sources].
abstract: The enzymatic determination of urea in spray-dried skim milk powders was transferred to a computer aided photometric analysing system. Sample preparation is optimal using ultrafiltration, but the direct use of a milk sample is also possible with this system. The precision including sample preparation as coefficient of variation was about 0.69%, the standard deviation of the assay was 0.115-0.135 at an average content of 5.4-5.5 mg urea per 100 ml skim milk. The method was tested on 147 spray-dried skim milk powders, which were of varying origin and collected at different times of the year (Jan.-Oct.). In this way a representative survey for the urea content of a great number of skim milk powders was possible. It was also shown, that the urea content is highly affected by season. It is very constant from February to May (0.25-0.26%), and rises from June to October up to nearly 0.32%.
mesh_terms: D000818:Animals; D002417:Cattle; D003201:Computers; D003611:Dairy Products / Q000032:analysis*; D010783:Photometry; D014508:Urea / Q000032:analysis*
chemical_list: D014508:Urea
vernacular_title: Eline rechnergesteuerte Schnellmethode zur Bestimmung von Harnstoff in Milcherzeugnissen: magermilchpulver unterschiedlicher Provenienz.