Solvent · polar protic
Ethanol C2H6O
Also: EtOH
Common HPLC/GC solvent. In HPLC it is a lower-toxicity, greener alternative to methanol/acetonitrile as an RP organic modifier (higher viscosity/backpressure and slightly higher UV cutoff than MeCN). Used as normal-phase strong eluent (high eluotropic strength), preparative/finished-product mobile phase, sample diluent, and needle/wash solvent. In GC it is a common volatile injection/dilution solvent and is one of the three Snyder selectivity probe solutes.
Compiled by Hemant RawatLast reviewed July 2026How we verify
Properties
- Formula
- C2H6O
- CAS number
- 64-17-5
- UV cutoff
- 210 nm
- Snyder polarity index (P′)
- 4.3
- Selectivity group
- II
- Eluotropic strength ε° (silica)
- 0.88
- Boiling point
- 78.37 °C
- Viscosity (25 °C)
- 1.07 cP
- Refractive index (nD²⁰)
- 1.3611
- Density
- 0.789 g/mL
- Water miscibility
- miscible
- USP <467> class
- Class 3
Safety
- highly flammable (flash point ~13 C)
- CNS depressant / intoxicant on ingestion
- eye irritant
- vapor forms explosive mixtures with air
- IARC Group 1 (alcoholic-beverage ingestion) - not a solvent-exposure classification
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 Ethanol 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, Ethyl acetate, Iso-octane, Methanol, Methyl ethyl ketone, 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, Water.
Check any specific pair on the interactive miscibility chart.
Using Ethanol in HPLC/GC
Common HPLC/GC solvent. In HPLC it is a lower-toxicity, greener alternative to methanol/acetonitrile as an RP organic modifier (higher viscosity/backpressure and slightly higher UV cutoff than MeCN). Used as normal-phase strong eluent (high eluotropic strength), preparative/finished-product mobile phase, sample diluent, and needle/wash solvent. In GC it is a common volatile injection/dilution solvent and is one of the three Snyder selectivity probe solutes.
Its Snyder polarity index is 4.3 (selectivity group II), and its UV cutoff of 210 nm is low enough for most 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.