Solvent · low polarity
Toluene C7H8
Also: methylbenzene, PhMe
Common nonpolar/mid-strength solvent in normal-phase HPLC and as a mobile-phase modifier; frequent GC/GC-MS diluent and headspace solvent; UV cutoff (~285 nm) limits use as a UV-transparent HPLC solvent but it is a useful UV probe/marker; sample diluent for nonpolar analytes, polymers, oils and resins; extraction and dissolution solvent; common GC calibration/reference and residual-solvent (USP <467> Class 2) analyte.
Compiled by Hemant RawatLast reviewed July 2026How we verify
Properties
- Formula
- C7H8
- CAS number
- 108-88-3
- UV cutoff
- 285 nm
- Snyder polarity index (P′)
- 2.4
- Selectivity group
- VII
- Eluotropic strength ε° (silica)
- 0.22
- Boiling point
- 110.6 °C
- Viscosity (25 °C)
- 0.56 cP
- Refractive index (nD²⁰)
- 1.4969
- Density
- 0.8669 g/mL
- Water miscibility
- immiscible
- USP <467> class
- Class 2
Safety
- highly flammable liquid and vapor
- reprotoxic (repro. tox. Cat. 2, suspected damage to unborn child)
- aspiration hazard (may be fatal if swallowed and enters airways)
- CNS depressant / neurotoxic on repeated exposure (STOT RE)
- skin and eye irritant
- not classified as carcinogen (IARC Group 3)
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 Toluene 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, Ethanol, 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, Triethylamine.
Partially miscible with: Dimethyl sulfoxide — mix only over a limited range.
Immiscible with: Water — these form two layers.
Check any specific pair on the interactive miscibility chart.
Using Toluene in HPLC/GC
Common nonpolar/mid-strength solvent in normal-phase HPLC and as a mobile-phase modifier; frequent GC/GC-MS diluent and headspace solvent; UV cutoff (~285 nm) limits use as a UV-transparent HPLC solvent but it is a useful UV probe/marker; sample diluent for nonpolar analytes, polymers, oils and resins; extraction and dissolution solvent; common GC calibration/reference and residual-solvent (USP <467> Class 2) analyte.
Its Snyder polarity index is 2.4 (selectivity group VII), and its UV cutoff of 285 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.