Testing for peroxides

How to test for peroxides

Learn how to perform peroxide testing using Quantofix 100 Dip Strips.

Testing intervals

Before each use, always perform a visual inspection of any PFC. Perform quantitative testing per the table below. 

Note regarding uninhibited PFCs

When referencing the table below, please keep in mind that more frequent testing is recommended for uninhibited PFCs.

PFC testing intervals
PFC classification Testing
Class A Test within 3 months of opening, or upon expiration. Then test every 90 days if the PFC is retained (not recommended).
Class B Always test prior to concentration or distillation. Test within 12 months of opening, or upon expiration, then test every 90 days if the PFC is retained (not recommended).
Class C Test within 12 months of opening, or upon expiration, then test every 90 days if the PFC is retained (not recommended).
Class D Test within 12 months of opening, or upon expiration, then test every 90 days if the PFC is retained (not recommended).

Visual inspection

If there are visual indicators of peroxide formation, do not touch, open, or otherwise disturb the container (inform all lab occupants of this). Call EH&S immediately for assistance.

Before using a peroxide-forming chemical (PFC), always begin by checking the date received, date of disposal, and date opened, and then proceed with a visual inspection. This can be accomplished by using a backlight or a side light with a non-hazardous light source, such as a flashlight. Visible indicators of peroxide formation in pure/non-contaminated PFCs include: 

Peroxide-forming chemical visual inspection for cloudiness

Cloudiness

Peroxide-forming chemical visual inspection for solid masses

Precipitated crystal formation appearing as chips, ice-like structures, or solid masses 

Peroxide-forming chemical visual inspection for floating wisp-like structures

Wisp-like structures floating in liquid 

Peroxide-forming chemical visual inspection for visible contamination

Other visible contamination or unexpected layering - Check around caps/lids

Quantitative testing

Ensure that the type of peroxide test you are using is appropriate for your material (for example, there are dip-strips for aqueous solutions and other kinds for organic solvents). 

  • If you are using the Quantofix Peroxide 100 test strips (available through ISU Chemistry Stores), always test for hydroperoxides by adding a drop of water to the test strip after the solvent has dried. (This process is noted on the container insert, but not on the container).  
  • For a dip-strip test, transfer a small amount of solvent to another container. To avoid potential contamination of the chemical, do not dip into the original container unless it is waste. 
    • Dip strips have an expiration date and must be stored according to the manufacturer's recommendations.
  • Follow the manufacturer’s instructions for completing the test and record the peroxide level, date, and your initials on the PFC label. 

Further actions will depend on the concentration of peroxide. 

Peroxide testing results

0-25 ppmDo not concentrate to near-dryness if peroxides are detected.
>25 ppmDo not concentrate or distill. Disposal is recommended.
≥100 ppmDo not use. Contact EH&S for assistance. Additional testing may be required prior to disposal.