If they are volatile you could use the GCMS.

Please check the following ResearchGate link.

https://www.researchgate.net/post/How_can_I_estimate_quantitatively_secondary_metabolites_in_plants

 Hello,

Phenolic lipids, flavonoids and triterpenes are typical metabolites of this family that HPLC commonly used procedure to assess them.

Thank full of u 

Parissa,

Firstly, you need to categorize the compounds of interest based on their polarity. Non-polar (use hexane), intermediate (ether) and polar (methanol). After, separating the respective extracts, you can then run CC and characterize by spectroscopic experiments. You can read one of my publication, may be helpful.

Thank you.