A quantitative testing method for the presence of peroxides in organic solvents and ethers exists as well:

EM Quant^R Peroxide Test, 0.5ppm to 25ppm

Note: The following instructions come from Galade Chemical, a distributor of the above product, and the authors of Water Testing Blog present them ‘as is’, with no expressed or implied guarantees of accuracy.

Volatile Ethers

Immerse a test strip for approximately 1 second in the solvent being tested and allow to evaporate.

Breathe on the reaction zone 4 times for 3-5 seconds each time. Alternatively, immerse briefly in distilled water.

Compare the reaction zone with the color scale.

Low Volatility Ethers

A. Immiscible with water.

Mix a sample of the ether to be tested with 3 times its volume of peroxide-free ether or petroleum benzine (boiling range 40-60°C).

Test as described under “Volatile ethers.”

Record the value indicated on the scale and multiply by 4.

B. Miscible with water

Mix a sample of the ether to be tested with 3 times its volume of distilled water.

Immerse a test strip for approximately 1 second.

Wait 2 minutes and compare with the color scale.

Convert the results as under “Conversion.”

Conversion

Allowing for dilution, 3mg/l on the color scale is equivalent to:

90mg/l tetrahydrofuran peroxide or 30mg/l peroxide calculated as H2O2

150mg/l dioxan peroxide or 45mg/l peroxide calculated as H2O2.