Elsevier

Analytical Biochemistry

Volume 16, Issue 2, August 1966, Pages 365-371
Analytical Biochemistry

Colorimetric estimation of amino acids and peptides with the Folin phenol reagent

https://doi.org/10.1016/0003-2697(66)90168-0Get rights and content

Abstract

By using the reaction of amino acids and peptides with the Folin phenol reagent to produce a blue color when divalent cobalt ions coexisted, a new colorimetric assay method of these substances has become possible. However, the color formed is not strictly proportional to concentrations, so that it may be necessary to make standard curves. Some other nitrogenous substances that can form chelates with divalent cobalt ions also react with the reagent, but ammonia or urea do not interfere.

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