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.


  • MSU Chemical Hygiene Plan 3.6.6
  • OSHA Standard 1910.1450 App A.
  • NPFA 45

Corrective actions:

Test peroxide formers periodically. Record testing dates and test results.

Peroxide-forming labels to record testing date and results are available from the EHS Safety Portal (Lab Label request).

Follow the same basic handling procedures as for flammable materials.

Safe Storage Period for Peroxide Forming Chemicals
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:

  1. 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).
  2. Shake with an equal quantity of the solvent to be tested.
  3. If peroxides are present, a red color will develop.

Potassium Iodide Detection Method

  1. 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).
  2. A resulting yellow color indicates the presence of 0.005% peroxides.

Inhibition of Peroxides

  1. Storage and handling under an inert atmosphere is a useful precaution.
  2. Addition of 0.001% hydroquinone, diphenylamine, polyhydroxyphenols, aminophenols or arylamines may stabilize ethers and inhibit formation of peroxides.
  3. Dowex-1® has been reported effective for inhibiting peroxide formation in ethyl ether.
  4. 100 ppm of 1-naphthol is effective for peroxide inhibition in isopropyl ether.
  5. Hydroquinone is effective for peroxide inhibition in tetrahydrofuran.
  6. 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.