Practical Protein Chemistry - A. Darbre 1989
Analytical Methods
Determination of protein attached to a solid support
Determination of amino groups by reaction with chloranil
This rapid method for detecting free amines and primary or secondary amino groups on a resin can be used to monitor the completion of Condensation reactions in solid-phase Peptide Synthesis or during the blocking of amino groups.
A saturated solution of chloranil (2,3,5,6-tetrachloro-1,4-benzoquinone) in toluene.
1. Place 1 mg of the peptide resin into a small test tube.
2. To detect primary amino groups, add 200 µl of acetaldehyde; for secondary amino groups, add 200 µl of acetone.
3. Add 50 µl of the chloranil solution and mix for 5 min at room Temperature.
In the presence of free amino groups on the resin surface, a green or blue coloration develops. The sensitivity is 5 µmol/g of resin, which is approximately the same as that of the ninhydrin test.
Last update: 06/08/2026
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