Letter | Published:

A New Colour Reaction for the D Vitamins

Nature volume 160, page 88 (19 July 1947) | Download Citation

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Abstract

While making a comparative study of the colour reaction of steroids and triterpenes, we have found a hitherto undescribed reaction produced by the D vitamins, producing a clear and limpid blue colour which we think might be used for quantitative estimations. We carry out Pettenkofer's reaction for the biliary acids as follows: to 1–2 mgm. calciferol is added 1-2 mgm. saccharose, and the whole is dissolved completely in 1–2 c.c. of absolute ethanol. Then we add two drops of concentrated sulphuric acid, giving a red colour; then six drops of sulphuric acid are added, giving a stark blue colour. The test-tube is shaken to mix the two layers. The colour diffuses throughout the liquid, and the definitive colour is a pale limpid blue.

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Affiliations

  1. Sección de Bioquímica, Institute Español de Fisiología y Bioquímica, Madrid.

    • V. VILLAR PALASÍ

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DOI

https://doi.org/10.1038/160088b0

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