a*****e
发帖数: 97 | 1 Run on LCMS, peak shows [M+H]222, [M+Na]244 under ESI positive mode.
UV-Vis shows a peak at 406nm(span 320-480nm) and the other at 264nm(spans
230-280nm).
We suspect it may be a quinone.
But MS/MS did not help much since the small molecule.
Went to Dictionary of natural product no luck.
Anyone help to identify the compound?
Thanks. |
b*******g
发帖数: 1309 | 2 get HR-MS，and NMR
if you have MS/MS，try metlin.scripps.edu,you can search your fragment ion.
but a high resolution MS is very important.
【在 a*****e 的大作中提到】
: Run on LCMS, peak shows [M+H]222, [M+Na]244 under ESI positive mode.
: UV-Vis shows a peak at 406nm(span 320-480nm) and the other at 264nm(spans
: 230-280nm).
: We suspect it may be a quinone.
: But MS/MS did not help much since the small molecule.
: Went to Dictionary of natural product no luck.
: Anyone help to identify the compound?
: Thanks.
|
a*****e
发帖数: 97 | 3 Nice.
Tried on Synapts HRMS gives 222.0999 and search database did not give the
compounds have 406nm and 264nm maxim.
We even search the database called AntiBase and came with no success. Now
understand the untargeted analysis is no easy.
【在 b*******g 的大作中提到】
: get HR-MS，and NMR
: if you have MS/MS，try metlin.scripps.edu,you can search your fragment ion.
: but a high resolution MS is very important.
|
a*****e
发帖数: 97 | 4 We have very limited sample(mg) and this compound(peak in LC) is in the
mixture, means NMR not working here.
【在 b*******g 的大作中提到】
: get HR-MS，and NMR
: if you have MS/MS，try metlin.scripps.edu,you can search your fragment ion.
: but a high resolution MS is very important.
|
t**w
发帖数: 82 | 5 hehe, 406nm and 264nm might from the impurities as you said it is a mixture.
【在 a*****e 的大作中提到】
: Nice.
: Tried on Synapts HRMS gives 222.0999 and search database did not give the
: compounds have 406nm and 264nm maxim.
: We even search the database called AntiBase and came with no success. Now
: understand the untargeted analysis is no easy.
|
a*****e
发帖数: 97 | 6 We even separated the peak from the mixture by LC fraction collector and
shows the 406 and 264nm. This peak is interesting coze it has the above UV
spectra with little fluoresence at(ex 420 em 480nm) and may be a new
cofactor. Hard to pinpoint a really new guy in metabolomics.
mixture.
【在 t**w 的大作中提到】
: hehe, 406nm and 264nm might from the impurities as you said it is a mixture.
|
b*******g
发帖数: 1309 | 7 here is our strategy:
try higher resolution MS,like FT-MS and Obri, to get more accurate m/z less
than 1ppm or even smaller and better isotope pattern-->this will help you to
predict the formula
second, did you try MS/MS search in Metlin or other database? you may find
some possible functional group from the MS/MS fragment. Together with
formula, you may propose a structure.
With UV information, refine you structure and synthesize the
compound. Then try MS/MS again, to see whether it matches with your unknown.
Since the mass is small, you may try GC-MS, GC-MS has a relative larger
database for search.
This is all I can have, if still not successful, give it up! it may take
another several years to figure it out.
【在 a*****e 的大作中提到】
: We have very limited sample(mg) and this compound(peak in LC) is in the
: mixture, means NMR not working here.
|
a*****e
发帖数: 97 | 8 nice approach!
We suspect it is a quinone type and made a couple of candidates but the uv
turns out mismatch. those database did not work at all. tried gc and did not
get anything since the quantity of sample and not volatile enough.
less
to
find
unknown.
【在 b*******g 的大作中提到】
: here is our strategy:
: try higher resolution MS,like FT-MS and Obri, to get more accurate m/z less
: than 1ppm or even smaller and better isotope pattern-->this will help you to
: predict the formula
: second, did you try MS/MS search in Metlin or other database? you may find
: some possible functional group from the MS/MS fragment. Together with
: formula, you may propose a structure.
: With UV information, refine you structure and synthesize the
: compound. Then try MS/MS again, to see whether it matches with your unknown.
: Since the mass is small, you may try GC-MS, GC-MS has a relative larger
|
k********s
发帖数: 320 | 9 Synapt accuracy is enough. Orbi won't help you much with accuracy
improvement over Synapt. Paste UV spectrum, MS/MS and also accurate mass
spectrum here so people can help you better.
What's the collision energy you were using? - Please also provide system
information, waters? Thermo? what model?
Do you have a GC-MS with Direct Probe (DI) capability?
not
【在 a*****e 的大作中提到】
: nice approach!
: We suspect it is a quinone type and made a couple of candidates but the uv
: turns out mismatch. those database did not work at all. tried gc and did not
: get anything since the quantity of sample and not volatile enough.
:
: less
: to
: find
: unknown.
|
E***n
发帖数: 308 | 10 other things you can do besides HRMS and NMR.
1, buy anthentic samples, confirm your proposal
2, make derivative of your tiny sample
3, is 264 absorbance stronger than 406? That tells you conjugation level of
your system.
4, contract for LC-NMR.
have fun!
【在 a*****e 的大作中提到】
: Run on LCMS, peak shows [M+H]222, [M+Na]244 under ESI positive mode.
: UV-Vis shows a peak at 406nm(span 320-480nm) and the other at 264nm(spans
: 230-280nm).
: We suspect it may be a quinone.
: But MS/MS did not help much since the small molecule.
: Went to Dictionary of natural product no luck.
: Anyone help to identify the compound?
: Thanks.
|
|
|
a*****e
发帖数: 97 | 11 tried chemically break the molecule by both acid and base hydrolysis and see
just mess on MS.
of
【在 E***n 的大作中提到】
: other things you can do besides HRMS and NMR.
: 1, buy anthentic samples, confirm your proposal
: 2, make derivative of your tiny sample
: 3, is 264 absorbance stronger than 406? That tells you conjugation level of
: your system.
: 4, contract for LC-NMR.
: have fun!
|
s*****e
发帖数: 1905 | 12 Coumarin type compound? |
m***o
发帖数: 77 | 13 What is the sample source? Plant, animal, bateria...? |
a*****e
发帖数: 97 | 14 Run on LCMS, peak shows [M+H]222, [M+Na]244 under ESI positive mode.
UV-Vis shows a peak at 406nm(span 320-480nm) and the other at 264nm(spans
230-280nm).
We suspect it may be a quinone.
But MS/MS did not help much since the small molecule.
Went to Dictionary of natural product no luck.
Anyone help to identify the compound?
Thanks. |
b*******g
发帖数: 1309 | 15 get HR-MS，and NMR
if you have MS/MS，try metlin.scripps.edu,you can search your fragment ion.
but a high resolution MS is very important.
【在 a*****e 的大作中提到】
: Run on LCMS, peak shows [M+H]222, [M+Na]244 under ESI positive mode.
: UV-Vis shows a peak at 406nm(span 320-480nm) and the other at 264nm(spans
: 230-280nm).
: We suspect it may be a quinone.
: But MS/MS did not help much since the small molecule.
: Went to Dictionary of natural product no luck.
: Anyone help to identify the compound?
: Thanks.
|
a*****e
发帖数: 97 | 16 Nice.
Tried on Synapts HRMS gives 222.0999 and search database did not give the
compounds have 406nm and 264nm maxim.
We even search the database called AntiBase and came with no success. Now
understand the untargeted analysis is no easy.
【在 b*******g 的大作中提到】
: get HR-MS，and NMR
: if you have MS/MS，try metlin.scripps.edu,you can search your fragment ion.
: but a high resolution MS is very important.
|
a*****e
发帖数: 97 | 17 We have very limited sample(mg) and this compound(peak in LC) is in the
mixture, means NMR not working here.
【在 b*******g 的大作中提到】
: get HR-MS，and NMR
: if you have MS/MS，try metlin.scripps.edu,you can search your fragment ion.
: but a high resolution MS is very important.
|
t**w
发帖数: 82 | 18 hehe, 406nm and 264nm might from the impurities as you said it is a mixture.
【在 a*****e 的大作中提到】
: Nice.
: Tried on Synapts HRMS gives 222.0999 and search database did not give the
: compounds have 406nm and 264nm maxim.
: We even search the database called AntiBase and came with no success. Now
: understand the untargeted analysis is no easy.
|
a*****e
发帖数: 97 | 19 We even separated the peak from the mixture by LC fraction collector and
shows the 406 and 264nm. This peak is interesting coze it has the above UV
spectra with little fluoresence at(ex 420 em 480nm) and may be a new
cofactor. Hard to pinpoint a really new guy in metabolomics.
mixture.
【在 t**w 的大作中提到】
: hehe, 406nm and 264nm might from the impurities as you said it is a mixture.
|
b*******g
发帖数: 1309 | 20 here is our strategy:
try higher resolution MS,like FT-MS and Obri, to get more accurate m/z less
than 1ppm or even smaller and better isotope pattern-->this will help you to
predict the formula
second, did you try MS/MS search in Metlin or other database? you may find
some possible functional group from the MS/MS fragment. Together with
formula, you may propose a structure.
With UV information, refine you structure and synthesize the
compound. Then try MS/MS again, to see whether it matches with your unknown.
Since the mass is small, you may try GC-MS, GC-MS has a relative larger
database for search.
This is all I can have, if still not successful, give it up! it may take
another several years to figure it out.
【在 a*****e 的大作中提到】
: We have very limited sample(mg) and this compound(peak in LC) is in the
: mixture, means NMR not working here.
|
|
|
a*****e
发帖数: 97 | 21 nice approach!
We suspect it is a quinone type and made a couple of candidates but the uv
turns out mismatch. those database did not work at all. tried gc and did not
get anything since the quantity of sample and not volatile enough.
less
to
find
unknown.
【在 b*******g 的大作中提到】
: here is our strategy:
: try higher resolution MS,like FT-MS and Obri, to get more accurate m/z less
: than 1ppm or even smaller and better isotope pattern-->this will help you to
: predict the formula
: second, did you try MS/MS search in Metlin or other database? you may find
: some possible functional group from the MS/MS fragment. Together with
: formula, you may propose a structure.
: With UV information, refine you structure and synthesize the
: compound. Then try MS/MS again, to see whether it matches with your unknown.
: Since the mass is small, you may try GC-MS, GC-MS has a relative larger
|
k********s
发帖数: 320 | 22 Synapt accuracy is enough. Orbi won't help you much with accuracy
improvement over Synapt. Paste UV spectrum, MS/MS and also accurate mass
spectrum here so people can help you better.
What's the collision energy you were using? - Please also provide system
information, waters? Thermo? what model?
Do you have a GC-MS with Direct Probe (DI) capability?
not
【在 a*****e 的大作中提到】
: nice approach!
: We suspect it is a quinone type and made a couple of candidates but the uv
: turns out mismatch. those database did not work at all. tried gc and did not
: get anything since the quantity of sample and not volatile enough.
:
: less
: to
: find
: unknown.
|
E***n
发帖数: 308 | 23 other things you can do besides HRMS and NMR.
1, buy anthentic samples, confirm your proposal
2, make derivative of your tiny sample
3, is 264 absorbance stronger than 406? That tells you conjugation level of
your system.
4, contract for LC-NMR.
have fun!
【在 a*****e 的大作中提到】
: Run on LCMS, peak shows [M+H]222, [M+Na]244 under ESI positive mode.
: UV-Vis shows a peak at 406nm(span 320-480nm) and the other at 264nm(spans
: 230-280nm).
: We suspect it may be a quinone.
: But MS/MS did not help much since the small molecule.
: Went to Dictionary of natural product no luck.
: Anyone help to identify the compound?
: Thanks.
|
a*****e
发帖数: 97 | 24 tried chemically break the molecule by both acid and base hydrolysis and see
just mess on MS.
of
【在 E***n 的大作中提到】
: other things you can do besides HRMS and NMR.
: 1, buy anthentic samples, confirm your proposal
: 2, make derivative of your tiny sample
: 3, is 264 absorbance stronger than 406? That tells you conjugation level of
: your system.
: 4, contract for LC-NMR.
: have fun!
|
s*****e
发帖数: 1905 | 25 Coumarin type compound? |
m***o
发帖数: 77 | 26 What is the sample source? Plant, animal, bateria...? |
