Peroxide forming chemicals
To avoid the risk of explosion, it is important to have a procedure for handling, storage and control of peroxide-forming chemicals (chemicals with hazard statement EUH019 or risk phrase R19, e.g. ethers). Karolinska Institutet and Karolinska hospital have developed a routine for peroxide forming chemicals (see under Documents).
Some chemicals (for example diethyl ether, tetrahydrofurane, dioxane) may over time form explosive peroxides. At high levels of peroxides it may be enough to shock or heat the container to ignite an explosion - and the higher the concentration of peroxides, the greater the risk of explosion. Parameters that have an impact on peroxide formation are:
- Whether the bottle is opened (oxygen accelerates the process)
- How old chemical is and how long it has been opened
- If it is exposed to sunlight and/or heat (accelerates the formation of peroxides)
- If the product is distilled (stabilizers are "purified" off)
- Keep the chemical in a dark and cool place
- Buy smaller amounts (1 L) at a time
- Always label the product with the delivery date and the date when the seal has been broken
- Opened products should not be stored more than one year
- Make regular self-checks with the test strip or KI test (see below)
Peroxide test strips are recommended, such as Sigma-Aldrich Quantofix (for more information see "Instruction peroxide forming chemicals" under Documents). In the absence of sticks you can easily determine if the chemical contains peroxides by doing a quick test.
Peroxide test with potassium iodide (KI) or sodium iodide (NaI):
Add 0.5 - 1 mL of test material (e.g. ether) at an equal volume of conc. acetic acid (HOAc) mixed with 0.1 g of NaI or KI
- Yellow color: low levels of peroxides
- Brown color: high content of peroxides
If peroxides are detected you are not allowed to use the chemical!
Disposal and waste management
If peroxides has been detected you are not allowed to use the chemical. If the chemical is cloudy and/or contains crystals it should not be used, moved or touched. For procedures and rules in different situations see "Instruction peroxide forming chemicals" under Documents!