Potassium Iodide Starch Oxidizer Test Paper [Vial of 100 Paper Test Strips] for Chlorine, Iodine and Peroxide Detection

I bought these things to detect low concentrations of peroxide, and they did a pretty good job for the price. I tested them in very diluted solutions, and they were able to go pretty low. It takes a bit for the color to show when the ppm is very low, and you have to be careful to keep your fingers off of any part that gets wet. I’d say you could reliably detect down to 30ppm, if you carefully follow the instructions and are patient with the results. I doubt you can tell much difference between concentrations above 3% (the highest I tested), but if you go substantially below that you can make a qualitative assessment of the relative concentration. But the best use for these is just to tell if peroxide is present or not.

Shipping was fast. Saved the day for a work trip where this was needed. Vial can be hard to open, but this keeps the paper from falling out.

Purchased this product to check for the presence of peroxides in an old bottle of diethyl ether. But first I tested the strips using some 3% hydrogen peroxide mixed with distilled water in different concentrations (0-100% in 20% increments). The label on the potassium iodide strips say the color will darken with higher concentrations, but all strips seem to have the same shade of purple. So these strips seem to work fine to check for the presents of peroxides, but wouldn't suggest using them to determine the concentration.

Starch-iodide papers are pretty generic. These are inexpensive, without skimping on the reagents.

Excellent