An improved gas chromatography with flame ionization detection (GC-FID) method for analysis of Octamethylcyclotetrasiloxane (D4), Decamethylcyclopentasiloxane (D5), and Dodecamethylcyclohexasiloxane (D6) cyclic siloxanes in silicone polymers containing OH-terminated siloxanes is described. From previous research in this area, it is known that generation of cyclic siloxanes can occur in the inlet of a GC depending on the composition of the silicone polymer being analyzed. Silylation is performed to cap the OH ends, thereby reducing this potential. Historical practice used hexamethyldisilazane (HMDZ) as the silylation reagent when analyzing these types of silicone containing polymers. Problems with interference was observed when analyzing low levels of cyclic siloxanes due to interfering peaks from the silylation reagent, HMDZ.  The objective was to improve the resolution of low level cyclic analysis. Several different techniques were attempted. The method described herein uses N-Methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) as the silylation reagent. A side-by-side comparison of the two different silylation reagents shows that using MSTFA produces a cleaner chromatogram while providing a simpler and safer sample preparation.<br/> <br/>

Improved resolution analysis of cyclic siloxanes in silicone polymers with OH-terminated siloxanes

256th National Meeting (2018)

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