Pyrolysis of reversed-phase high-performance liquid chromatographic packing materials

Pyrolysis coupled with gas chromatography and or mass spectrometry, allows the identification of the bonded chain in reversed-phase high-performance liquid chromatographic stationary phases. It is possible to distinguish whether an octadecylated reversed-phase was prepared with a trifunctional(e.g., trichloro or monofunctional dimethyl, e.g., dimethyl-ethoxy) octadecylsilane from the relative heights of the heptadecene and octadecene peaks. The nature of the pyrolysis products was investigated. No carbon chains are formed with more carbon atoms than in the bonded chain. The peak area ratio of methane to that of the combined C₄ products allows one to deduce whether the reversed-phase was deactivated as not by reaction with a trimethylsilylating reagent (end-capping).