GC Stationary Phase

GC methods are divided into two classes depending on the nature of stationary phases; gas-solid chromatography (GSC) and gas-liquid chromatography (GLC). GSC has solid adsorptive material and solute particles are removed from mobile phase by electrostatic forces. GLC has a thin layer of liquid coated or bonded on the surface of an inert particle or on the walls of the column where solute particles are retained in the liquid phase based on their partition coefficients. The primary necessity of a stationary phase is to provide sample separation sustaining phase integrity over a reasonable period of time. It should be stable for the chemical and thermal changes. Selectivity, peak symmetry, analysis time, degree of separation, peak tailing are few parameters that should be considered before choosing a stationary phase. Carbowax 20M is a polar liquid phase suitable as stationary phase for gas chromatography. It consists of two units of (HC₂-CH₂O)₆₀₀ with OH terminals connected through a hydrophobic portion. This structure of the polymer makes it suitable for being used as a solvent for polar molecules such as cyclodextrin derivatives. It exhibits good selectivity toward alcohols, diols and aromatic isomeric molecules.

Synthesized specifically to be purer, of narrow molecular weight range, and without trace catalysts or impurities for use as a GC stationary phase.

Carbowax 20M may be used to test different relative amounts of crosslinking reagents by coating the inner wall of the capillary, to optimizing the capillary column performance.