A new method for analysis of coke on catalysts

Both on-line dynamic headspace (HS) sampling and high temperature capillary separation were used in the GC-MS analysis of the volatile components of c oke. The results showed that an open-tubular trap with a thick liquid film is better than a trap packed with Tenax-GC adsorbent for preconcentration o f the volatile components of coke. Compared with the latter and with the pr eviously reported analysis of soluble coke with solvent extraction, the pro posed method can determine more components of coke on catalysts, allowing t he determination of polynuclear aromatics with up to nine rings. The mean r ecovery of reference compounds was 97.1% with RSDs of 1.5-4.8%, sufficient to meet the requirements for the analysis of coke on catalysts.