Ccxl. Spectrographic Studies on the Antimony Trichloride Reaction for Vitamin A. I. the Relation between Tintometer Readings and Spectral Absorption of the Blue
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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...
متن کاملCxxiv. Studies on Colour Tests for Sterols and for Vitamin A
IN the first paper of this series an account was given of some sterol tests in which blue colours were obtained very similar in appearance to those given by arsenic trichloride or antimony trichloride with cod-liver oil, and attributed to vitamin A. On account of this close resemblance, it appeared desirable next to undertake a spectroscopic study of the "vitamin" colours with the object of dis...
متن کاملCxxviii. Spectrophotometric Investi- Gations of the New Vitamin a Colour Test. by Eugene Rosenthal And
COLORIMETRIC determination of vitamin A has frequently been based upon the Carr-Price reaction, namely the production of a blue colour when vitamin A is added to a saturated solution of antimony trichloride in chloroform, which shows two absorption maxima at 606 m,u and at 572 m,u, respectively. This reaction has the following drawbacks: (1) the blue colour is not specific for vitamin A, being ...
متن کاملSpectrophotometric Study of a New Colorimetric Reaction of Vitamin A* by Albert E. Sobel
This paper deals with a new calorimetric reaction of vitamin A with glycerol 1,3-dichlorohydrin (which we henceforth will refer to as GDH) that appears to be suitable for the quantitative estimation of this vitamin. The estimation of vitamin A in vitro has been the subject of many reviews in recent years (l-6). The two widely used methods at present are the ultraviolet absorption at 325 to 328 ...
متن کاملA 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...
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