Gamma radiation effects on polydimethylsilane stationary phases for use inpacked-column gas chromatographic analyses

Gamma radiation induced immobilization of several polydimethylsilane liquid stationary phases For use in packed-column gas chromatographic separations has been studied. Extraction tests show that moderate doses of gamma radia tion (80-140 kGy) are sufficient to produce significant (90%) immobilizatio n of most polydimethylsilanes onto Chromosorb supports. although a molecula r mass effect is; seen. Thermal stability also increases significantly with radiation dose, suggesting higher temperature use with smaller volatility losses. Infrared spectra confirm the continued presence of the stationary p hase on the support after thermal stability tests and after exhaustive in-c olumn washing. The column chromatographic behavior of the immobilized phase s is equal to or better than that of the unirradiated phases, except for hi gher doses (300 kGy) of gamma-radiation. Columns prepared from gamma-immobi lized polydimethylsilane have been used successfully in analyses where colu mn contamination from high boiling materials requires frequent column recup eration.