Crosslinking of alkylpolysiloxane filsm on various types of glass surfaces including fused silica using γ-radiation of a⁶⁰cobalt-source. Comparison to crosslinking by thermal peroxid treatment

Summary

Crosslinking of alkylpolysiloxane stationary phases, especially in thick film capillary columns, is useful for the homogenous coating of fused silica and pretreated alkaliglass surfaces. The films of the stationary liquid are immobilized against solvent rinsing using CH₂Cl₂, pentane, and acetone, and maintain homogenity even at high temperature. Various doses of γ-radiation from a⁶⁰Co. source were used for the crosslinking instead of the thermal peroxid treatment recently described by other authors. The effect of the γ-radiation crosslinking-procedure was investigated in comparison to the peroxid method in regard of: decrease of stationary phase content by solvent rinsing, separation efficiency, tailing behaviour, and bleeding of the columns obtained. Similar results as with the cumylperoxid-treatment were achieved using the γ-radiation-method. By γ-radiation no polar functional groups or moleculs are introduced into the stationary phase, however, as with the peroxid method. Less than 20% of the various stationary liquids are usually removed from the columns by solvent rising after crosslinking using both methods depending on the doses of radiation and the cumylperoxid concentration applied respectively.