N Hexane HPLC

N-Hexane for HPLC is a high-purity, non-polar solvent specifically manufactured for use as a mobile phase in High-Performance Liquid Chromatography (HPLC), particularly for Normal-Phase (NP-HPLC) applications .

Key Properties and Specifications

This solvent is distinguished by its rigorous purity standards to ensure it does not interfere with analytical results. Key specifications from major suppliers include :

• Purity: Typically ≥95% for general HPLC use, with some grades offering ≥97% or ≥99% purity .

• Physical Properties: Colorless liquid, boiling point ~69°C, density ~0.66 g/cm³ .

• Key Impurity Limits:

  • UV Absorbance (Transmission): A critical parameter. High transmittance at low wavelengths ensures a clean baseline, e.g., ≥25% at 200nm, ≥85% at 220nm, ≥98% at 245nm .

  • Non-Volatile Matter (Residue after Evaporation): Very low, typically ≤0.0003% to ≤0.0005% .

  • Water Content (Karl Fischer): Usually ≤0.01% .

  • Acidity: Very low, often ≤0.0005% (as acetic acid) .

Role in HPLC

In Normal-Phase HPLC, n-hexane acts as the primary, non-polar component of the mobile phase . It is mixed with a more polar solvent (such as isopropanol, ethyl acetate, or chloroform) to create an eluent of a specific polarity . In this mode, polar analytes interact more strongly with the polar stationary phase (like silica) and are retained longer, while non-polar analytes elute faster . n-Hexane is particularly suitable for separating lipophilic compounds, long-chain alkanes, and compounds that are sparingly soluble in aqueous conditions .

Quality and Safety

HPLC-grade n-hexane undergoes extensive purification processes like highly efficient distillation and solid-phase absorption to remove UV-absorbing and other interfering impurities . It is often filtered through a 0.2 µm membrane and packaged under inert gas or in amber bottles to prevent contamination .

Safety is paramount: n-Hexane is a highly flammable liquid (Flash Point: ~-22°C) and presents serious health risks . Key hazards include:

• H225: Highly flammable liquid and vapor .

• H304: May be fatal if swallowed and enters airways .

• H361f: Suspected of damaging fertility .

• H373: May cause damage to organs (e.g., nervous system) through prolonged or repeated exposure .

Standard safety precautions include keeping it away from all sources of ignition, using it only in a fume hood, and wearing appropriate personal protective equipment (gloves, eye protection