Solvent · nonpolar
n-Heptane C7H16
Also: heptane
Nonpolar mobile phase / weak eluent in normal-phase HPLC and adsorption chromatography (often replacing hexane for lower toxicity); sample diluent and extraction solvent for lipophilic analytes; reference standard for octane rating; GC applications and as a nonpolar carrier/diluent. Low P' and near-zero eluotropic strength make it the weak end of normal-phase gradient systems.
Compiled by Hemant RawatLast reviewed July 2026How we verify
Properties
- Formula
- C7H16
- CAS number
- 142-82-5
- UV cutoff
- 200 nm
- Snyder polarity index (P′)
- 0.1
- Selectivity group
- — (non-selective)
- Eluotropic strength ε° (silica)
- 0.01
- Boiling point
- 98.4 °C
- Viscosity (25 °C)
- 0.39 cP
- Refractive index (nD²⁰)
- 1.3876
- Density
- 0.684 g/mL
- Water miscibility
- immiscible
- USP <467> class
- Class 3
Safety
- highly flammable (H225)
- aspiration hazard - may be fatal if swallowed and enters airways (H304)
- skin irritant (H315)
- narcotic / drowsiness or dizziness (STOT SE 3, H336)
- very toxic to aquatic life with long-lasting effects (H410/H411)
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 n-Heptane mixes with
Miscible with: 1-Propanol, 1,2-Dichloroethane, 1,4-Dioxane, 2-Propanol, Acetic acid, Acetone, Benzene, Carbon tetrachloride, Chloroform, Cyclohexane, Dichloromethane, Diethyl ether, Ethanol, Ethyl acetate, Iso-octane, Methyl ethyl ketone, Methyl isobutyl ketone, MTBE, n-Butanol, n-Butyl acetate, n-Hexane, n-Pentane, Pyridine, tert-Butanol, Tetrahydrofuran, Toluene, Triethylamine.
Partially miscible with: Methanol, N-Methylpyrrolidone, N,N-Dimethylacetamide, N,N-Dimethylformamide — mix only over a limited range.
Immiscible with: Acetonitrile, Dimethyl sulfoxide, Water — these form two layers.
Check any specific pair on the interactive miscibility chart.
Using n-Heptane in HPLC/GC
Nonpolar mobile phase / weak eluent in normal-phase HPLC and adsorption chromatography (often replacing hexane for lower toxicity); sample diluent and extraction solvent for lipophilic analytes; reference standard for octane rating; GC applications and as a nonpolar carrier/diluent. Low P' and near-zero eluotropic strength make it the weak end of normal-phase gradient systems.
Its Snyder polarity index is 0.1, and its UV cutoff of 200 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.