[yas]

Hi,
I am a new comer to analytical chemistry, normally I am plant biology grad-student. I am asking for the help from you, analysts! Thanks in advance.

My pain is - cuticular wax analysis using GC.
I extracted waxes from plant and separated them on main classes on TLC. So, I identified hydrocarbons, FFA, fatty alcohols, sterols, triterpenoids, 3 bands left no identified.  My plan is to go for GC-FID (MS) with every identified class. But I am confused with calibration using external standards. Do I need to have for every class special standard mixture? For example for class hydrocarbons - alkanes ranging in chain lenght from C21-C36 or for FAA-mixture of C20-C31 fatty acids and so on?  I checked the kit of mixtures is expensive and if I need for every class new kit it is ...oooo$. Please advise me something....

Another question, did anyone have an experience with fatty acid analysis on BP 5 (5% phenyl.1% vinyl methyl polysiloxane). I know it is not the best variant for  fatty acids (FAME) but i do not have Carbowax (polyethylene glycol st.phase) column. Should not I even try BP- 5?


thank you, thank you

yas

[Rivet]

If you can verify that individual species within a given class do not vary much in response factor, then a couple of representative compounds could be used for calibration of each class.