Spectrographic studies on the antimony trichloride reaction for vitamin A

Studies on the reaction of certain carotenoids with antimony trichloride.

Since both carotene and vitamin A yield a blue color with SbCla, attempts to determine t,he vitamin quantitatively in a mixture depend, among other things (1, 2)) upon the accuracy with which the blue color due to carotene can be estimated. Values published for the blue equivalent of carotene range from 3.5 to 13, calculated as micrograms of apparent vitamin A per 100 y of carotene (3). This di...

Ccxl. Spectrographic Studies on the Antimony Trichloride Reaction for Vitamin A. I. the Relation between Tintometer Readings and Spectral Absorption of the Blue

The colorimetric reaction between vitamin A2 aldehyde and antimony trichloride.

1. Columns of Sephadex G-25 have been used for the preliminary fractionation of tryptic digests of casein. 2. Fractions from Sephadex columns have been examined for their ability to stimulate the growth of a strain of Streptococcus equi8imili8. Maximum stimulatory activity appeared to be localized in a fairly narrow region of the total peptide material. 3. Further fractionation of peptides deri...

A photoelectric spectrophotometer suitable for the measurement of vitamin A by the antimony-trichloride reaction.

The measurement by visual methods of the fleeting blue colour of vitamin A in the antimony-trichloride reaction presents considerable difficulties which can be largely overcome by the use of photoelectric methods with corresponding increase in accuracy. The photoelectric spectrophotometer now described was constructed in I 941 when no comparable instrument of this type was commercially availabl...

A Study of the Antimony Trichloride Color Reaction for Vitamin A. Ii. the Dilution Curve of Cod Liver Oil with Antimony

In a previous paper of this series (1) we have shown that while the dilution curve for cod liver oil with antimony trichloride is not a linear function, a comparison can be made between the colorimetric assay of vitamin A in certain fish oils, with a chloroform solution of antimony trichloride, and the biological assay upon the same oils, when certain precautions are taken. In a second paper (2...