Wiesner reaction
The Wiesner reaction (also called Wiesner phloroglucinic hydrochloric acid reaction ) is a method used in biochemistry to detect lignin in lignified material. Dilute hydrochloric acid is sprayed onto the substance to be examined and then an alcoholic solution of phloroglucinol is added dropwise. The presence of lignin is indicated by a purple to purple color.
The Wiesner reaction also plays a role in assessing the cause of wood discoloration. According to the chemist Karl Kratzl, these come about either through dyes or through wood color reactions in which uncolored substances chemically change the lignin. The wood color reactions are based either on oxidation processes (Mäule reaction according to C. Mäule, Georg Jayme ) or reactions with, for example, phenols and amines .
Web links
- Lexicon of chemistry: Wiesner reaction , Spectrum Academic Publishing House, Heidelberg, 1998 online excerpt
- Karl Pfoser: Comparative experiments on lignification reactions and fluorescence (from the Plant Physiological Institute of the University and the Federal Institute for Food Analysis, Vienna; presented at the meeting on December 11, 1958), online excerpt as a PDF file