Possible identity of a compound? - 未名空间MITBBS历史存档

Possible identity of a compound?# Chemistry - 化学

s*r2012-10-31 07:10

1 楼

本来以为自己够倒霉了，看了本版抱怨才知道加拿大签证现在这么难.
有几个问题请教,认识的人就飘过好了:
1.面签的使馆有哪些?
看官网的意思是好象只有NY和LA.
但貌似本版没有上LA签证的.
2.新的规定好象也划区签证了吧?
好象LA和DC分开2个区.跨区行不啊? 急签,LA似乎可以面签.
3.LA有那种代办签证的,说最快一个礼拜就能拿到.这一类可靠么?

a*e2012-10-31 07:10

2 楼

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.

s*r2012-10-31 07:10

3 楼

没人理呢

b*g2012-10-31 07:10

4 楼

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*82012-10-31 07:10

5 楼

寄签LA被据的飘过~

a*e2012-10-31 07:10

6 楼

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.

k*r2012-10-31 07:10

7 楼

你查consulate最准，这个最近是说改就改

a*e2012-10-31 07:10

8 楼

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.

c*n2012-10-31 07:10

9 楼

好多规矩都是最近改的，官网上咋说的那就是咋样的了

【在 s**********r 的大作中提到】

: 本来以为自己够倒霉了，看了本版抱怨才知道加拿大签证现在这么难.
: 有几个问题请教,认识的人就飘过好了:
: 1.面签的使馆有哪些?
: 看官网的意思是好象只有NY和LA.
: 但貌似本版没有上LA签证的.
: 2.新的规定好象也划区签证了吧?
: 好象LA和DC分开2个区.跨区行不啊? 急签,LA似乎可以面签.
: 3.LA有那种代办签证的,说最快一个礼拜就能拿到.这一类可靠么?

t*w2012-10-31 07:10

10 楼

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.

s*r2012-10-31 07:10

11 楼

请问你说的consulate最准，是说他们官网的是吧？
我怕他们政策改了，网上没来得及改。。。

【在 k*****r 的大作中提到】

: 你查consulate最准，这个最近是说改就改

a*e2012-10-31 07:10

12 楼

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.

s*r2012-10-31 07:10

13 楼

请问他们说什么原因了么？
谢谢分享！

【在 a******8 的大作中提到】

: 寄签LA被据的飘过~

b*g2012-10-31 07:10

14 楼

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.

y*l2012-10-31 07:10

15 楼

你是哪类签证？
我是工签，还在焦急等待中。。。

【在 s**********r 的大作中提到】

: 本来以为自己够倒霉了，看了本版抱怨才知道加拿大签证现在这么难.
: 有几个问题请教,认识的人就飘过好了:
: 1.面签的使馆有哪些?
: 看官网的意思是好象只有NY和LA.
: 但貌似本版没有上LA签证的.
: 2.新的规定好象也划区签证了吧?
: 好象LA和DC分开2个区.跨区行不啊? 急签,LA似乎可以面签.
: 3.LA有那种代办签证的,说最快一个礼拜就能拿到.这一类可靠么?

a*e2012-10-31 07:10

16 楼

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

s*r2012-10-31 07:10

17 楼

给你回站内信了

【在 y*****l 的大作中提到】

: 你是哪类签证？
: 我是工签，还在焦急等待中。。。

k*s2012-10-31 07:10

18 楼

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*n2012-10-31 07:10

19 楼

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*e2012-10-31 07:10

20 楼

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*e2012-10-31 07:10

21 楼

Coumarin type compound?

m*o2012-10-31 07:10

22 楼

What is the sample source? Plant, animal, bateria...?

a*e2012-10-31 07:10

23 楼

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*g2012-10-31 07:10

24 楼

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*e2012-10-31 07:10

25 楼

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*e2012-10-31 07:10

26 楼

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*w2012-10-31 07:10

27 楼

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*e2012-10-31 07:10

28 楼

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*g2012-10-31 07:10

29 楼

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*e2012-10-31 07:10

30 楼

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*s2012-10-31 07:10

31 楼

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*n2012-10-31 07:10

32 楼

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*e2012-10-31 07:10

33 楼

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*e2012-10-31 07:10

34 楼

Coumarin type compound?

m*o2012-10-31 07:10

35 楼

What is the sample source? Plant, animal, bateria...?