PEG-400 (Polyethylene Glycol 400) Research Co-Solvent
PEG-400 (CAS 25322-68-3) is a liquid polyether with an average molecular weight near 400, supplied in a 30 mL bottle as a co-solvent and carrier for laboratory work. Its usefulness comes from sitting between the aqueous and lipophilic worlds: it is fully water miscible while still dissolving many compounds that water alone will not carry, which is why it appears so often in co-solvent systems alongside DMSO.
Solvent Properties & Research Context
A distribution, not a single molecule. “400” is an average of a chain-length distribution, not a discrete molecular weight. Lots differ slightly in distribution, which matters for viscosity-sensitive or precisely formulated work.
Water miscible. Dilutes into aqueous buffer without phase separation, unlike a lipid carrier.
Viscous. Substantially more viscous than water or ethanol at room temperature; allow for slower pipetting and incomplete transfer when measuring small volumes.
Hygroscopic. Absorbs atmospheric moisture, so water content in an opened container rises over time.
Research Applications
Co-solvent systems for compounds too poorly soluble for a single vehicle.
Formulation and solubility screening.
Vehicle controls at matched final concentration.
Analytical Documentation
Molecular weight distribution and water content vary by manufacturing lot. Kimera Chems does not publish a single fixed purity figure for this item; refer to the batch-specific Certificate of Analysis (COA) issued for the lot received.
Storage & Handling
Store at controlled room temperature. Keep tightly closed.
Storage guidance is a house recommendation. Analytical documentation is per-lot release testing.
