Why do anion exchange resins smell?
Anion exchange resins, especially strong base anion exchange resins in the hydroxide form, may emit odors such as a dead fish smell. The main cause is release of very low levels of amines from the resin (trimethylamine for Type I strong base resins). Amines, such as trimethylamine, have a very low odor threshold (5 ppb) and will be smelled at levels well below the hazardous limits established by regulatory agencies. Trimethylamine is also released by decomposing fish, hence the association of the resin odor with a dead fish. If desired, the amines can be quickly rinsed from the resin using deionized water before placing the resin into service. Another option to minimize odor is to select a Type II strong base anion exchange resin which uses a dimethylethanolamine functional group which has reduced odor. Please consult the Product Center for assistance in selecting a Type II anion resin.
