The library I am using is of some help, but the compounds we have don't seem to match any of the suggestions.
We are trying to identify marine sterols from sponges. If someone has the information for Petrosterol specifically, that would be of great help too.
Thank you all.
www.lipidlibrary.aocs.org has some mass spectra for variously derivatised sterols in the archive section. Otherwise the book "Analysis of Sterols" by John Goad has some mass spectral information in. The NIST website also sometimes has mass spectral information, but not for every compound. You also have to search by compound so you need to have some idea what might be in your samples.
Thank you both for the answers. Unfortunately, the massbank doesn´t have a hit for Petrosterol (and the suggestions for the mass we have, 412,40 do not fit the fragmentation pattern). I had also tried the lipidlibrary, which usually is of great help (specially for fatty acids). But for sterols does not have much...
My problem is that I am almost sure that what we have is Petrosterol but how can we be sure if we don´t find the fragmentation pattern for comparison...?
Try also:
Metlin (http://metlin.scripps.edu/index.php)
LipidMAPS (http://www.lipidmaps.org/tools/index.html)
Hi,
would this fragmentation pattern fit your unknown (thought to be petrosterol)?
412, 397, 394, 379, 370, 355, 352, 337, 328, 327, 314, 301, 300, 299, 273, 271, 255, 253, 231 and 213.
from Gauvin et al. "Cyclopropane-containing sterols in the marine sponge Petrosia spheroïda", Comp. Biochem. Physiol., Part B, 1998, 121, 451–456
If you can isolate it (e.g., fractionation by HPLC with an RP-18 column), 1D and 2D NMR experiments on your pure compound would help a lot in determining the structure, if you have access to NMR.
best regards,
JR
Hi,
I know that paper and it fits...more or less. I think with relative % for the fragmentation pattern we could be more sure. That was why I was trying to find it but all papers I have seen about petrosterol do not have that information specified.
The higher % for fragmentation we have is:
271 (100), 412 (84), 55 (56), 213 (48), 145 (46), 394 (38), 105 (38) (...)
We also have tried isolation but we have experienced change in the pattern and masses, so it seams these compounds are a bit unstable/sensitive.
Thanks for the suggestions, though.
Silvia
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