DMSO 99.9% or DMSO 70%: differences, storage and why it solidifies
DMSO (dimethyl sulfoxide, CAS 67-68-5) is a colourless organic solvent widely used in technical applications for its great ability to dissolve both polar and non-polar substances. At Aquapurelife we offer it in two concentrations: DMSO 99.9% and DMSO 70%. Here we explain their differences and how to store it.
DMSO 99.9%
- What it is: dimethyl sulfoxide practically free of water (minimum content of 99.9%).
- Characteristics: density of approximately 1.10 g/cm³, melting point close to 18.5 °C and boiling point of about 189 °C. It is highly hygroscopic: it absorbs moisture from the air if left open.
- Formats: amber glass from 125 ml to 1 L (see DMSO 99.9% in glass) and HDPE jerrycans of 5, 10 and 20 L (see DMSO 99.9% in jerrycan).
DMSO 70%
- What it is: a solution of DMSO 99.9% diluted with purified water to 70%.
- Characteristics: because it contains water, its freezing point is much lower than that of pure DMSO, so it stays liquid at the usual temperatures of a home or warehouse.
- Formats: amber glass from 125 ml to 1 L (see DMSO 70%), lots and jerrycans from 5 to 20 L (see DMSO 70% jerrycans).
Comparison table
| Feature | DMSO 99.9% | DMSO 70% |
|---|---|---|
| Composition | DMSO ≥ 99.9% | 70% DMSO + 30% purified water |
| Solidifies at | ≈ 18.5 °C | Well below 0 °C |
| Preparation | Concentrated product | Already diluted, ready to use |
| Formats | 125 ml to 1 L and 5 to 20 L | 125 ml to 1 L and 5 to 20 L |
If you want both, the DMSO Duo Kit includes 250 ml of DMSO 99.9% and 250 ml of DMSO 70%.
Why has my DMSO turned solid?
This is completely normal. DMSO 99.9% crystallises below about 18 °C, which is common in winter or during transport. It does not mean the product is spoiled: its composition does not change.
How to return it to a liquid state: leave the closed container at a warm room temperature (20-25 °C) for a few hours, or immerse it, always closed, in lukewarm (not hot) water. Avoid direct heat sources, flames or microwaves. Once liquid, it may solidify again if the temperature drops: that is not a problem.
How to store DMSO
- Closed container: DMSO absorbs moisture from the air; close it tightly after each use.
- Protected from light: that is why we use amber glass or opaque HDPE.
- Temperature: cool, dry place, ideally between 18 and 25 °C for the 99.9% if you want to keep it liquid.
- Compatible containers: glass and HDPE. Avoid plastics such as polystyrene or PVC, which DMSO can attack. More information in the packaging guide.
- Keep out of the reach of children and consult the SDS.
Frequently asked questions
Where to buy DMSO in Spain?
At Aquapurelife we pack DMSO in Spain and ship it within 24-72 h. You will find all formats in the DMSO collection; for large volumes, see B2B and bulk.
Can DMSO 70% be prepared from 99.9%?
Technically it is a dilution with purified water, but DMSO generates heat when mixed with water and is hygroscopic. If you need the 70%, it is more convenient and more accurate to buy it ready-made.
Why does DMSO smell?
A slight sulphurous odour is characteristic of this substance and its decomposition traces. Keeping it tightly closed and protected from light helps keep it in good condition.
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