How should 3% hydrogen peroxide solution be stored so that it does not lose its activity?

Hydrogen peroxide is unstable: light, heat and contact with metals or dirty surfaces gradually break it down into water and oxygen, and it loses its activity. That is why the solution is sold in dark bottles.

Basic storage rules:

• A dark place: direct sunlight speeds up decomposition. A first-aid kit, a closed cupboard or a drawer will do.
• Room temperature: keep it away from heat sources such as radiators or the stove. There is no need to freeze the solution.
• A tightly closed bottle: put the cap back on after each use, since contact with air also promotes decomposition.
• Do not pour it into metal containers: metals catalyse the decomposition of peroxide.

If the solution no longer fizzes when applied to a dirty surface, or has changed colour, it has most likely already decomposed and lost its activity. In that case there is no point in using it for its intended purpose.

The advantage of the 100 ml bottle is that it gets used up relatively quickly, so long-term storage is not usually a pressing issue. Even so, it is worth following the storage conditions from the first day after opening.