Types of water Sterile or DI or Distilled
Water used in medical labs can have a wide range in labeling and the types of uses.
Sterile describes a water that has no living organisms in it. This could be done by boiling the water , autoclaving it at say 15 psi for 15 minutes or by passing through an ultrafiltraion membrane.
Deinized water DI for short is water that has passed through a bed of cation and anion exchange resins. These will remove metal ions ( say iron or sodium)and cations (Say chloride). Ther can still be other impurities in in such as bacteria, mold or nonionic compounds such as ethanol or other water soluble organics.
Distillated water has been boiled and the steam then condensed. Distilling is the oldest method for producing reagent grade water. Distilled water will be free of metal ions or cations. It should also be free of dissolved inorganics or organics and may well be sterile depending on how it was distilled and stored.
Modern water system use UF, RO, Ion exhange and Carbon. Antonia Gilligan - 21 November 2008
