Properties of Column Phases

Chemically bonded stationary phases are covalently bonded to the fused silica surface, are highly temperature stable, and can be solvent rinsed for cleaning from matrix contaminations. In contrast, cross-linked stationary phases are not bonded to the surface, only use chemical links between the polymer chains. 

Oxygen degrades the stationary phases. For column storage it is recommended to seal the ends with a septum, and store in a dark place, typically the column box, to prevent stationary phase damage by oxidation, moisture and UV light. Not used installed GC columns should get a low carrier gas flow with spUt open at low flow as well (prepare a standby method at low oven temperature). Ah column manufacturers provide upper and lower temperature hmits for use of the individual columns and stationary phases  

Least polar bonded phase Boiling point separations for solvents, petroleum products, pharmaceuticals Minimum temperature -60 °C Maximum temperature 340 -430 °C Helix structure 

Nonpolar, bonded phase Boiling point, point separations for aromatic compounds, environmental samples, flavours, aromatic hydrocarbons 

Weakly polar, similar to 8% phenylsiloxane Ideal for GC-MS coupling because of very low bleeding All environmental samples, can be used universally Volatile halogenated hydrocarbons, solvents -polyaromatic hydrocarbons, pesticides, only column that separates all PCB congeners Minimum temperature -20 ° C Maximum temperature 370 °C 

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