Solvent · polar aprotic
Methyl ethyl ketone C4H8O
Also: MEK, 2-butanone
Medium-polarity ketone solvent used in GC (including as a headspace/dilution solvent) and as a strong normal-phase eluent; also an extraction/sample-prep solvent. Its high UV cutoff (~329 nm) makes it unsuitable as a low-wavelength UV-HPLC mobile phase.
Compiled by Hemant RawatLast reviewed July 2026How we verify
Properties
- Formula
- C4H8O
- CAS number
- 78-93-3
- UV cutoff
- 329 nm
- Snyder polarity index (P′)
- 4.7
- Selectivity group
- VIa
- Eluotropic strength ε° (silica)
- —
- Boiling point
- 79.64 °C
- Viscosity (25 °C)
- 0.43 cP
- Refractive index (nD²⁰)
- 1.3788
- Density
- 0.8049 g/mL
- Water miscibility
- partial
- USP <467> class
- Class 3
Safety
- highly flammable liquid and vapor
- eye irritant
- respiratory/skin irritant
- CNS depressant at high vapor concentrations
- not classified as carcinogen (IARC/NTP)
Reference only. Solvents can be flammable, toxic, or peroxide-forming. Always consult the Safety Data Sheet (SDS) and your lab's protocols before handling.
What Methyl ethyl ketone mixes with
Miscible with: 1-Propanol, 1,2-Dichloroethane, 1,4-Dioxane, 2-Propanol, Acetic acid, Acetone, Acetonitrile, Benzene, Carbon tetrachloride, Chloroform, Cyclohexane, Dichloromethane, Diethyl ether, Dimethyl sulfoxide, Ethanol, Ethyl acetate, Iso-octane, Methanol, Methyl isobutyl ketone, MTBE, n-Butanol, n-Butyl acetate, n-Heptane, n-Hexane, N-Methylpyrrolidone, n-Pentane, N,N-Dimethylacetamide, N,N-Dimethylformamide, Pyridine, tert-Butanol, Tetrahydrofuran, Toluene, Triethylamine.
Partially miscible with: Water — mix only over a limited range.
Check any specific pair on the interactive miscibility chart.
Using Methyl ethyl ketone in HPLC/GC
Medium-polarity ketone solvent used in GC (including as a headspace/dilution solvent) and as a strong normal-phase eluent; also an extraction/sample-prep solvent. Its high UV cutoff (~329 nm) makes it unsuitable as a low-wavelength UV-HPLC mobile phase.
Its Snyder polarity index is 4.7 (selectivity group VIa), and its UV cutoff of 329 nm limits low-wavelength UV detection.See what the polarity index means and the full UV cutoff table.
Sources
- University of Toronto (TRACES) — Burdick & Jackson — Solvent UV cutoff table (absorbance = 1 AU, 1 cm cell)
- Stenutz / L. R. Snyder — Solvent polarity index (P′) and selectivity groups
- NIST — Chemistry WebBook — thermophysical properties (BP, density, refractive index)
- PubChem (NIH/NLM) — Compound property records (physical constants, CAS, formula)
- USP <467> / ICH Q3C — Residual Solvents — solvent classification (Class 1/2/3)
Values are compiled from public references and were last verified July 2026. See ourmethodologyfor how we source and verify. Always confirm critical values against primary references and the SDS.
Related solvents
Other selectivity group VIa to compare with Methyl ethyl ketone.