AEC (3-amino-9-ethylcarbazole) is used as a chromogen substrate in immunoblotting and immunohistochemistry.

AEC produces a rose-red colour during the enzymatic degradation of H2SO4 by horseradish peroxidase. Each tablet contains 5 mg of AEC and dissolves in approx. 5 minutes. 1 tablet is added 1 ml of 96 % alcohol, followed by addition of distilled water to 10 ml.

This will give a solution of pH 5.1 + 0.1 buffered with 20 mM citrate.

Stability life time is 18 months at 4°C.