Good morning Ajeet, you wrote that you want to identify phytochemical compounds of fumes - is this right? Then I recommend you GC/MS. How is the fume generated (by heat, pyrolysis) and how do you sample the fume? Often gaseous compounds are trapped on an adsorbent (e.g. TENAX TA) and then thermal desorbed. Greetings Markus

Purge and trap would be my suggestion

I agree with the previous submitters.  Perhaps headspace GC/MS may be an option, as well.