Tetramethyl-p,p′-sildiphenylene ether–dimethyl, diphenylsiloxane copolymers as stationary phases in gas chromatography

A 33% tetramethyl-p,p′-sildiphenylene ether (SDPE)–67% dimethylsiloxane copolymer was prepared and characterized by 1H and 29Si NMR spectroscopy. The random copolymer was coated on fused-silica capillary columns and used as stationary phase in GC. Highly deactivated capillary columns with high separation efficiency and a working range from −10 to 400 °C were obtained. For comparison, a commercially available capillary column with an SDPE–diphenyl, dimethylsiloxane terpolymer was tested. The selectivity of SDPE phases is best described by the assumption that an SDPE unit is equivalent to two dimethylsiloxy and one diphenylsiloxy group. Both capillary columns exhibited low column bleed in combination with seriously increased elution temperatures.