Peroxides are tested regularly and documented
It is recommended to chemically test for peroxides periodically.
A label affixed to the outside of the container should indicate date of last test, and test results.
References:
- MSU Chemical Hygiene Plan 3.6.6
- OSHA Standard 1910.1450 App A.
- NPFA 45 9.2.3.4
Corrective actions:
Test peroxide formers periodically. Record testing dates and test results.
Peroxide-forming labels to record testing date and results are available here: Chemical Label Request
Follow the same basic handling procedures as for flammable materials.
| Peroxide Forming Chemicals: Description | Safe Storage Period |
|---|---|
| Unopened chemicals from manufacturer | 18 months |
| Opened containers: Chemicals in Part A | 3 months |
| Opened containers: Chemicals in Parts B and D | 12 months |
| Opened containers: Uninhibited chemicals in Part C | 24 hours |
| Opened containers: Inhibited chemicals in Part C | 12 monthsa |
a Do not store under inert atmosphere, oxygen required for inhibitor to function.
Detection and Inhibition of Peroxides: Basic Protocols
Ferrous Thiocyanate Detection Method
Ferrous thiocyanate will detect hydroperoxides with the following test:
- Mix a solution of 5 ml of 1% ferrous ammonium sulfate, 0.5 ml of 1N sulfuric acid and 0.5 ml of 0.1N ammonium thiocyanate (if necessary, decolorize with a trace of zinc dust).
- Shake with an equal quantity of the solvent to be tested.
- If peroxides are present, a red color will develop.
Potassium Iodide Detection Method
- Add 1 ml of a freshly prepared 10% solution of potassium iodide to 10 ml of ethyl ether in a 25 ml glass-stoppered cylinder of colorless glass protected from light (both components are clear).
- A resulting yellow color indicates the presence of 0.005% peroxides.
Inhibition of Peroxides
- Storage and handling under an inert atmosphere is a useful precaution.
- Addition of 0.001% hydroquinone, diphenylamine, polyhydroxyphenols, aminophenols or arylamines may stabilize ethers and inhibit formation of peroxides.
- Dowex-1® has been reported effective for inhibiting peroxide formation in ethyl ether.
- 100 ppm of 1-naphthol is effective for peroxide inhibition in isopropyl ether.
- Hydroquinone is effective for peroxide inhibition in tetrahydrofuran.
- Stannous chloride or ferrous sulfate is effective for peroxide inhibition in dioxane.
Peroxides Test Strips
These test strips are available from EM Scientific, cat. No. 10011-1 or from Lab Safety Supply, cat. No. 1162. These strips quantify peroxides up to a concentration of 25 ppm. Aldrich Chemical has a peroxide test strip, cat. No. Z10,168-0, that measures up to 100 ppm peroxide. The actual concentration at which peroxides become hazardous is not specifically stated in the literature. A number of publications use 100 ppm as a control value for managing the material safely.
Please note that these methods are BASIC protocols. Should a researcher perform one of these methods, all safety precautions should be thoroughly researched.
Any compound testing positive for peroxide formation must be disposed of via MSU EHS.