Dimethyl sulfoxide, shortened to DMSO, is an organosulfur compound with the molecular formula C2H6OS and the CAS number 67-68-5. It is a colourless, hygroscopic liquid at room temperature and ranks among the most widely used polar aprotic solvents in industry because it dissolves both polar and non-polar compounds, is fully miscible with water and with most organic solvents, and boils near 189 °C. Because the molecule is produced from dimethyl sulfide, which in turn comes from methanol and hydrogen sulfide, the quoted price per kilogram tracks both the solvent market and the sulfur and methanol feedstock markets.
Why the Price per kg Varies So Widely
The first driver is grade. Bulk industrial material in drums, IBC containers or ISO tank lots is the least expensive, while pharmaceutical grade material costs far more because it requires additional purification steps and strict testing for residual impurities, water content and trace metals. The second driver is order volume and packaging: a full tanker load normally costs less per kilogram than a few drums, because packaging, handling and freight are spread over more material.
Grade and purity: technical, industrial, electronic and pharmaceutical grades carry different test programmes.
Order volume: drum, IBC, ISO tank and bulk vessel quantities price differently.
Packaging and logistics: steel drums, lined drums and heated transport add cost in cold weather.
Feedstock and energy: methanol, hydrogen sulfide and steam costs move with energy markets.
Freight, duty and exchange rate: cross-border shipments add landed-cost variables.
Documentation: a full regulatory dossier adds cost for regulated applications.
Indicative Price Ranges
| Grade | Indicative price per kg | Typical use |
|---|---|---|
| Industrial / technical, bulk | About 5 to 20 USD | Reaction solvent, cleaning, polymer processing |
| Pharmaceutical grade | About 100 to 500 USD and above | Drug substance processing, formulation, cryopreservation media |
These figures are indicative ranges reported in supplier and market commentary and are affected by volume and delivery terms. They are not a quotation and should not be used to build a budget. A firm price must always be confirmed against the exact grade, quantity, packaging and destination for the specific shipment.
Quality Parameters Buyers Should Compare
A unit price is only meaningful next to the specification it covers. Buyers comparing offers should confirm the assay by gas chromatography, the water content by Karl Fischer titration, the colour on the platinum-cobalt scale as described in ASTM D1209, the non-volatile residue, the trace metal profile and the impurity limits that matter for the intended use. Batch number, manufacturing date, retest or expiry date and packaging type should appear on both the certificate of analysis and the shipping documents.
For regulated applications the product must meet the relevant pharmacopoeia monograph or an agreed in-house technical specification, and the supplier should provide a safety data sheet and the transport documentation required for a combustible liquid.
Reading a Price Against Total Landed Cost
The cheapest offer per kilogram is not always the cheapest supply. Freight, import duty, insurance, storage and the cost of any quality failure all belong in the comparison, as does reliability of lead time. A producer that keeps a verified stock position and ships on schedule can be more economical than a lower-priced offer with long or unpredictable delivery, because a stock-out on the production line costs far more than a few dollars per kilogram.
Safety, Storage and Handling Notes
DMSO penetrates intact skin rapidly and can carry dissolved substances into the body with it. Gloves must therefore be selected carefully and contaminated solutions must never be handled bare-handed. The liquid is combustible rather than highly flammable, with a high flash point near 95 °C, but it should still be kept away from open flames and strong oxidising agents. Prolonged or repeated skin contact may cause irritation or allergic reactions, and vapour should be avoided in enclosed spaces.
Store the product in tightly closed containers in a cool, dry and ventilated area, away from heat and incompatible materials, and follow the safety data sheet supplied with the shipment. Because DMSO freezes near 18 °C, lines and containers may need gentle warming in cold climates before transfer.
Frequently Asked Questions
Q: What is the CAS number of DMSO?
The CAS number of dimethyl sulfoxide is 67-68-5.
Q: How much does DMSO cost per kg?
Indicative bulk prices for industrial grade material are roughly 5 to 20 USD per kilogram, while pharmaceutical grade material is reported at roughly 100 to 500 USD per kilogram or more, depending on volume and specification.
Q: Why is pharmaceutical grade DMSO more expensive?
It requires additional purification and strict impurity testing, which raises production and quality control costs and adds documentation work.
Q: Is DMSO flammable?
DMSO is combustible, with a high flash point near 95 °C, so it is not classified as a highly flammable liquid but must be kept away from ignition sources.
Q: Is DMSO miscible with water?
Yes. It mixes with water in all proportions and is also miscible with most organic solvents, including alcohols, ketones and esters.
Q: Why does DMSO penetrate the skin?
It readily crosses biological membranes and can carry dissolved substances with it, so protective gloves and careful handling are essential.