Gas Chromatographic Retention Characteristics of Different Polysiloxane Oligomers

Abstract

The effects on the Kovats and McReynolds indices for a modified set of Rohrschneider solutes h~ve.been examined using two different batches of a •.commercial polysiloxane stationary phase, Dow-Coming DC-710, and five pure• oligomers isolated from the mixture. The significant differences that were found between batches appear to be due primarily to changes .in the percentage of one oligomer, the cyclic pentamer. This finding emphasizes the desirability of using a pure stationary phase as well as carefully specifying the column temperature in order to improve intra.-and inter-laboratory comparisons of retention indices.

Instrumentation for Reliably Determining Porous Silicon Photoluminescence Responses to Gaseous Analyte Vapors

“…The current system temperature range is from ambient to ∼470 K with a precision of ∼0.5 K. The GC column contains a 1:1 mixture of polydimethylsiloxane and polydiphenylsiloxane that separates species approximately based on their boiling point. 42 The column output is connected to a home-built, stainless steel flow cell (100 µL volume) with a fused silica optical window. The ap-pSi sample for study is positioned within the flow cell and the analyte stream is directed to pass over the ap-pSi surface.…”