I am working on isolation of Asiaticoside (molecular weight is 959.12) from the Centella asiatica plant. I got methanolic extract after applying the grounded leaves to Soxhelt, then I have applied the extract to silica gel column, used chloroform/methanol as a mobile phase and I got some fractions. I need to check if these fractions have the compound that I am looking for or not? TLC did not work with me. So I need another way to check. The only machine available at this time is GC MS. So are there any recommendations to use GC MS for this experiment and what are the recommended conditions?
Other suggested methods are appreciated
No, certainly not, Helmi. There is no way to have such an heavy and quite polar molecule (trisaccharide saponin) going through the GC column!
To my opinion, the best analytical tools would be an HPLC (or better UPLC) system on a reverse-phase (C18) column and coupled either to an ESI-MS detector or to an Evaporative Light Scattering (ELS) Detector (or even better, to both detectors).
Indeed, the problem with these saponins is that they do not absorb in the UV spectrum and DAD is not able to detect any of them.
Thanks so much Joseph, I appreciate ur answer
you supported me with very excellent information. tq again
Can ask 1 more question here, please?
Can I use FTIR to check if the sample has asiaticoside or not ? my question in the case I have standard, I run it on the FTIR then run the sample and compare the results? is this OK?
thanks in advance
Yes, if you are sure of the purity of your own sample and if the bands of the fingerprint area matches the ones of the standard (in frequency), there is no chance that they are different.
I agree with Joseph, this 958 Da compound cannot be analised by GC-MS. Best is HPLC.
I got a nice separation and detection using UHPLC-TOF-MS (elution at approx 30% ACN in a 5-95% gradient of Water+0.1% FA -> ACN+0.1% FA on a C18 column) in negative ESI mode.
- Badges
- Science topic
- Similar topics
- Analytical Chemistry
- Extraction