Does Hydrogen Peroxide Expire? Storage & TestingFaizan Khan
Hydrogen peroxide is an organic compound, consisting of two hydrogen atoms and two oxygen atoms.
A fun fact is that hydrogen peroxide is actually water (H2O), it just happened to invite an extra oxygen molecule into its bubble and formed (H2O2). This fact will help clear small confusions as you read on.
Hydrogen peroxide is well known amongst households, for it is a disinfectant that is widely used within homes. However, there are many other uses of hydrogen peroxide including being used in food industries and disinfecting pools and ponds.
With such a commonly used chemical, it is necessary to be equipped with all its relevant information to maintain safety when handling it as well as to effectively reduce costs!
What is Food-Grade Hydrogen Peroxide?
Hydrogen peroxide comes in many concentration levels that cater to different functions.
- 3% hydrogen peroxide- Household peroxide.
- 6-10% hydrogen peroxide- Hair bleaching peroxide.
- 90% hydrogen peroxide- Industrial peroxide.
Food-grade hydrogen peroxide is that which has a 3% concentration level. This means that it is made up of 97% water and 3% hydrogen peroxide. This is also known as a medical-grade hydrogen peroxide which is easily found in a brown bottle in supermarkets or drug stores.
Food-grade peroxides can go up to a concentration level of 35%, but it is best to avoid them for they become more dangerous as the levels increase.
These ‘Food-Grade’ peroxides are used by the food industry to fulfill several functions such as bleaching or processing certain foods.
Hydrogen Peroxide Shelf Life
A food-grade 3% hydrogen peroxide is likely to last around 3 years if it is kept in a sealed bottle at room temperature. This is because it breaks down at a rate of 0.5% per year.
Its lifetime drastically falls as the seal is broken- resulting in the peroxide solution only lasting 3-6 months.
Hydrogen peroxide solutions that have a 30-35% concentration level are prone to degrading more quickly. If the seal is unbroken its effectiveness will last up to a year, whereas with a broken seal it will only be of use for about 30 to 45 days.
For this reason, it is very important to quickly use up hydrogen peroxide once you open the bottle. You must also make sure to avoid opening multiple bottles at once for it will only result in a lot of hydrogen peroxide being wasted.
Decomposition of Hydrogen Dioxide
The bubbles that hydrogen dioxide famously produces are an indicator of the solution decomposing.
2H2O2 →2H2O +O2 is the chemical equation that represents this process.
Hydrogen dioxide breaks down into water and oxygen, and the sizzling bubbles are oxygen gas being released. This is also referred to as oxidation.
This process of decomposition is constant and yet is not always recognizable, although it becomes more detectable as the process speeds up which is when it comes in contact with various catalysts. These catalysts include transition metals such as the enzyme catalase and iron in the blood.
An enzyme catalase is found in most living organisms which include humans as well as bacteria. Its primary function is to protect cells from hydrogen peroxide by quickly deactivating the compound.
When hydrogen peroxide is used to treat wounds, it oxidizes and results in cells being destroyed. These include both healthy tissue and microbes. The damage to the healthy tissues usually repairs over time.
Factors Affecting the Shelf Life of Hydrogen Peroxide
Effect of Light on H2O2 Shelf Life
Hydrogen peroxide is most reactive to light and for that reason, hydrogen dioxide is usually provided in a brown or opaque bottle. This solution is usually stored with a stabilizer in a dark bottle.
Effect of Temperature on H2O2 Shelf Life
It’s quite simple- the higher the temperature the faster the rate of decomposition. Whereas, the lower the temperature the slower the rate of decomposition.
It is for this reason that hydrogen peroxide must be stored in a cool dark place.
The potential of Hydrogen (pH)
pH is a measure of the concentration of hydrogen ions present in a solution. The pH and concentration of hydrogen peroxide are inversely proportional.
This means that the higher the pH the lower the concentration of the solution, and the lower the pH the greater the concentration of the solution.
This leads us to the fact that the rate of decomposition increases along with concentration levels.
Storage Requirements and Conditions of Hydrogen Peroxide
To help you retain the efficiency of hydrogen peroxide, we have created a list of requirements that a longer-lasting peroxide demands. Check off the complete list to ensure you are efficiently storing the solution!
- Do not open a bottle of food-grade hydrogen peroxide unless you need to use it. This will prevent it from reacting to light, air, and water and hence decrease the probability of it decomposing.
- H2O2 is usually sold in brown bottles, make sure you do not transfer it to any other bottle, especially one that is of a lighter color. We all need protection from direct contact with sunlight, including hydrogen peroxide!
- Store it in a cool dark place, away from the reach of children.
- Although hydrogen dioxide is non-flammable it may still catch on fire or explode under certain circumstances. To avoid any such happenings keep it in a fire-proof area away from any sources of heat.
- Avoid dipping your finger or swab into the solution, so that the effectiveness of the remaining liquid is not reduced through faster decomposition.
How To Test if the Hydrogen Peroxide Is Expired
You may be expecting a chemical solution to have a complex procedure to test its efficiency, but you’re in for a shock.
All you need to do is spill a bit of hydrogen peroxide in the sink. If it sizzles, it’s still good, if it doesn’t it’s likely that it has expired. (Similar to soda!)
The hydrogen peroxide does not change visually or through its smell, and hence the given technique is the only way to truly tell if a solution has become redundant in its functions.
The lack of bubbles when it expires is due to it converting into the water and hence being unreactive to air.
What Products Does Hydrogen Peroxide React With?
Since we have discussed the reaction of hydrogen dioxide with elements like oxygen, air, and water that cause it to decompose, here are some other products that it reacts to. These products won’t cause it to decompose but will rather cause an explosion!
A mixture of ammonia and hydrogen peroxide is often used during a hair bleaching process. However, if you are not a professional, you may end up creating a very toxic gas that can harm your well-being if it is inhaled.
Hydrogen peroxide and vinegar are popular for being germ-killing duo. However, homeowners must be cautious when combining these two. Never mix the two solutions at once, they are supposed to be used one after another.
Chlorine or Bleach
Intermixing bleach and hydrogen peroxide creates oxygen gas so violently and abruptly that it results in an explosion.
It is a cleaning law that two cleaning products must not be merged for they do not necessarily create a stronger disinfectant.
They do however create corrosive reactions like poisonous fumes which may cause death- as with the case of a manager- Ryan Baldera– who attempted to clean two merged reactive liquids.
Well Wishes for Your Long Life Peroxide!
Now that you are aware of how to correctly handle and store hydrogen peroxide, you’ll be enjoying lower bills dedicated to hydrogen dioxide.
Through hydro-goggles you now pass as a paramedic, and I wish you all the best in your journey of preserving hydrogen dioxide!