Adamkiewicz reaction
The Adamkiewicz reaction is part of a biochemical test used to detect the presence of the amino acid tryptophan in proteins. When concentrated sulfuric acid is combined with a solution of protein and glyoxylic acid, a red/purple colour is produced. It was named after its discoverer, Albert Wojciech Adamkiewicz. Pure sulphuric acid and a minimal amount of pure formaldehyde, along with an oxidizing agent introduced into the sulphuric acid, allow the reaction to proceed. In this oxidation-reduction reaction, the oxidizing agent can be sodium amalgam, which reduces oxalic acid, while the reducing agent is nitric acid , which oxidizes an alcohol. Reduction of the oxalic acid is done in a sulphuric acid solution while avoiding a temperature increase inside the cathode. Once the reduction has ended, the oxalic acid is diminished and the freed glyoxylic acid produces the indol molecules, which gives the red/purple color.