The determination of carotene and vitamin A in butter and margarine
Goodwin, T.W.; Morton, R.A.
Analyst 71: 15-20
ISSN/ISBN: 0003-2654 PMID: 21011768 DOI: 10.1039/an9467100015
The difficulties inherent in the chemical assay of total vit. A activity in margarine are discussed and illustrated by several examples. Detn. of [image]. at 325 m[mu] is useless owing to irrelevant absorption and with SbCl3 at 620 m[mu] is complicated by production of color from other constituents than vit. A. The latter can be approx. detd., after the vit. blue has faded, and subtracted from the total blue (Edisbury's method). The reasonableness of this procedure was supported by recovery and by biologic tests.