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LC-MS/MS紧急求助！

LC-MS/MS紧急求助！# Chemistry - 化学

f*d2010-07-10 07:07

1 楼

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t*g2010-07-10 07:07

2 楼

打个比方
我1月份开的传统IRA（non-deductible），5000块，
到了5月份，赚了300块
然后我5月份把整个传统IRA转成了Roth IRA
从那时候到12月份，又赚了700块（所以最后是5000+300+700=6000块）
那么我的问题：
1。5月份转换的时候需要缴税吗？是只需要给那300块钱缴税吗？
2。5月份转换时缴税跟年底缴税有区别吗？
3。那后来赚的700块钱永远也不需要缴税？
谢谢！

q*22010-07-10 07:07

3 楼

发信人: ironmud (草鞋凿冰), 信区: TrustInJesus
标题: Re: 在爱主的道路上: 彼此切实相爱!
发信站: BBS 未名空间站 (Fri May 28 02:30:39 2010, 美东)
看样子你是学到了一点新东西。
关于在这些经节的教导，其中一些传统现在早已没有人守了。不是它们不好，是过时了。

b*n2010-07-10 07:07

4 楼

我猜是中央电脑
其次是他师傅, 不过那样违反人物性格

m*b2010-07-10 07:07

5 楼

其他smartphone上用吗？

m*k2010-07-10 07:07

6 楼

Can any MS expert help me out here? I use API3000 trying to detect certain
compounds. The method was set up, just like what I did for other compounds.
The first injection was just solvent (MeOH) but I saw unusually high
baseline. Changed to different column, same problem. Changed to different
method, fine．　Ｃｈａｎａｇｅｄ　ｔｏ　ｏｔｈｅｒ　ｓａｍｐｌｅｓ，　ｆｉｎ
ｅ　ａｓ　ｗｅｌｌ．　Ｎｅｖｅｒ　ｓａｗ　ｔｈｉｓ　ｈｉｇｈ　ｂａｓｅｌｉｎ
ｅ　ｂｅｆｏｒｅ．I checked the method again but I don't see a problem. Is
that sort of contamination in the line or in the ion sou

f*n2010-07-10 07:07

7 楼

1. yes, yes, assuming you don't have any other traditional IRAs
2. what?
3. yes, assuming you don't take it out early

l*r2010-07-10 07:07

8 楼

骑大茄?

t*u2010-07-10 07:07

9 楼

只要你能用那个卡

【在 m***b 的大作中提到】

: 其他smartphone上用吗？

e*r2010-07-10 07:07

10 楼

very simple ja. but i am too sleepy now

t*g2010-07-10 07:07

11 楼

thanks
关于问题2,我的意思是,如果我5月份转换的时候,让我的IRA公司代扣税
和年底的时候,我自己缴税,交的数量有没有区别?
因为我5月份的时候只赚了300,可是年底IRA账面上一共赚了1000
那么假如年底报税,IRS怎么知道在这1000块钱里头,有700块是5月份以后才赚,不需要缴
税的呢?

【在 f*******n 的大作中提到】

: 1. yes, yes, assuming you don't have any other traditional IRAs
: 2. what?
: 3. yes, assuming you don't take it out early

y*l2010-07-10 07:07

12 楼

这个我觉得现在的许乐, 打破那面玻璃好玩一样, 霸道真气大成的人是很厉害的.

【在 b****n 的大作中提到】

: 我猜是中央电脑
: 其次是他师傅, 不过那样违反人物性格

m*k2010-07-10 07:07

13 楼

have u wake up yet.....please

U*S2010-07-10 07:07

14 楼

税单里有IRA转换一项。

s*82010-07-10 07:07

15 楼

七大家族，他们的对话内容说不定被电脑实况转播了。

【在 b****n 的大作中提到】

: 我猜是中央电脑
: 其次是他师傅, 不过那样违反人物性格

L*r2010-07-10 07:07

16 楼

改变方法后，基线又降下来了，说明SOURCE没有被污染，当基线很高的时候，看看都
是什么离子，可能溶剂污染了。希望能有更好的建议。

g*s2010-07-10 07:07

17 楼

I think they should be two accounts.

【在 t**g 的大作中提到】

: thanks
: 关于问题2,我的意思是,如果我5月份转换的时候,让我的IRA公司代扣税
: 和年底的时候,我自己缴税,交的数量有没有区别?
: 因为我5月份的时候只赚了300,可是年底IRA账面上一共赚了1000
: 那么假如年底报税,IRS怎么知道在这1000块钱里头,有700块是5月份以后才赚,不需要缴
: 税的呢?

s*n2010-07-10 07:07

18 楼

应该是中央电脑。

【在 b****n 的大作中提到】

: 我猜是中央电脑
: 其次是他师傅, 不过那样违反人物性格

m*k2010-07-10 07:07

19 楼

谢谢建议！我也觉得source应该没有污染，在这个injection后跑了其他的sample 很
正常，不过用的也是同样的溶剂。因为我用的是triple quadrupole MRM, 设定了要看
我要的化合物，所以没有看到其他的离子。我会把溶剂换掉试试看。也可能是我inject
的MeOH污染了。都换掉都换掉。
而且这两个化合物，carry over还挺严重的，方法可能也要改。。。。

【在 L****r 的大作中提到】

: 改变方法后，基线又降下来了，说明SOURCE没有被污染，当基线很高的时候，看看都
: 是什么离子，可能溶剂污染了。希望能有更好的建议。

b*n2010-07-10 07:07

20 楼

果然, 一点新意都没有

【在 b****n 的大作中提到】

: 我猜是中央电脑
: 其次是他师傅, 不过那样违反人物性格

m*k2010-07-10 07:07

21 楼

still have the problem.............can anyone help????? seems only see this
high baseline for this method! Solvent is totally fine!!

B*G2010-07-10 07:07

22 楼

下一步许乐要去百慕大了?跟林半山搞上。

【在 b****n 的大作中提到】

: 果然, 一点新意都没有

S*x2010-07-10 07:07

23 楼

跟你的ion pair有关。
如果灵敏度不是问题，就调调DP和CE. MP可以用ACN,还不行的换ion pair或者试试
negative

.

【在 m******k 的大作中提到】

: Can any MS expert help me out here? I use API3000 trying to detect certain
: compounds. The method was set up, just like what I did for other compounds.
: The first injection was just solvent (MeOH) but I saw unusually high
: baseline. Changed to different column, same problem. Changed to different
: method, fine．　Ｃｈａｎａｇｅｄ　ｔｏ　ｏｔｈｅｒ　ｓａｍｐｌｅｓ，　ｆｉｎ
: ｅ　ａｓ　ｗｅｌｌ．　Ｎｅｖｅｒ　ｓａｗ　ｔｈｉｓ　ｈｉｇｈ　ｂａｓｅｌｉｎ
: ｅ　ｂｅｆｏｒｅ．I checked the method again but I don't see a problem. Is
: that sort of contamination in the line or in the ion sou

w*82010-07-10 07:07

24 楼

1.你“Ｃｈａｎａｇｅｄ　ｔｏ　ｏｔｈｅｒ　ｓａｍｐｌｅｓ”，你的MRM方法和那
个certain compound一样吗？
2.你所说的high baseline，是指出现在MRM的某一个transition里还是所有的？
3.你把mobile phase换成ACN，看看还会有那么高的background吗？
4.所谓carry over的问题，是不是inject太多样品了，稀释一下，如果还不行，就改
gradient方法吧。
我和楼上看法一样，估计是ion pair的问题。如果条件允许，换成negative ion mode
好了。

L*r2010-07-10 07:07

25 楼

#
Dear group members,
Welcoming the LC-MS/MS users to comment on the plausible causes for
high background noise observed sometimes in LC-MS/MS analysis. What
are the different attributing factors responsible for high to very
high baseline level and what are the different measures to reduce the
baseline.
Also how best can we explain the rise in baseline level while doing
analysis in SIM mode compared to MRM mode.
Looking forward to have your responses.
Regards
Neel K Mohan
Back to the Top
# On 7

m*k2010-07-10 07:07

26 楼

Thanks for replying!
Sensitivity is good, proved by other samples. I tuned the instrument for
these particular compounds and got optimized DP and CE, those are what I
used in the method. You think the DP and CE need to adjusted? MP is ACN.

【在 S***x 的大作中提到】

: 跟你的ion pair有关。
: 如果灵敏度不是问题，就调调DP和CE. MP可以用ACN,还不行的换ion pair或者试试
: negative
:
: .

m*k2010-07-10 07:07

27 楼

Thanks!
1. No, different MRM method based on different compound. I just wanted to
see if the instrument sensitivity was the problem.
2. The high baseline showed up when I injected the blank solvent (ACN). The
MRM method was set to look at two compounds (two sets of Q1/Q3), for both
channel I could see high baseline but apparently the baseline in one channel
is way higher than the other.
3. I'm using ACN as the mobile phase. I even changed the LC method from
gradient to isocratic, 60% ACN all the

【在 w**********8 的大作中提到】

: 1.你“Ｃｈａｎａｇｅｄ　ｔｏ　ｏｔｈｅｒ　ｓａｍｐｌｅｓ”，你的MRM方法和那
: 个certain compound一样吗？
: 2.你所说的high baseline，是指出现在MRM的某一个transition里还是所有的？
: 3.你把mobile phase换成ACN，看看还会有那么高的background吗？
: 4.所谓carry over的问题，是不是inject太多样品了，稀释一下，如果还不行，就改
: gradient方法吧。
: 我和楼上看法一样，估计是ion pair的问题。如果条件允许，换成negative ion mode
: 好了。

S*x2010-07-10 07:07

28 楼

How can you test sensitivity for Compund A by using Compound B?
For different compounds, same instrument may have different sensitivity.
Auto tune can help, but it may not be the best method. You can use auto tune
method as start point to make the adjustment.
Also, please check the spary needle to make sure it's not too close.

【在 m******k 的大作中提到】

: Thanks for replying!
: Sensitivity is good, proved by other samples. I tuned the instrument for
: these particular compounds and got optimized DP and CE, those are what I
: used in the method. You think the DP and CE need to adjusted? MP is ACN.

S*x2010-07-10 07:07

29 楼

If you want to check sensitivity, the best way will be calibration.
Comparing with last time calibration data, you can find whether sensitivity
changed or not.

The
channel

【在 m******k 的大作中提到】

: Thanks!
: 1. No, different MRM method based on different compound. I just wanted to
: see if the instrument sensitivity was the problem.
: 2. The high baseline showed up when I injected the blank solvent (ACN). The
: MRM method was set to look at two compounds (two sets of Q1/Q3), for both
: channel I could see high baseline but apparently the baseline in one channel
: is way higher than the other.
: 3. I'm using ACN as the mobile phase. I even changed the LC method from
: gradient to isocratic, 60% ACN all the

S*x2010-07-10 07:07

30 楼

就怕negative没有碎片

mode

【在 w**********8 的大作中提到】

m*k2010-07-10 07:07

31 楼

Thanks a lot!
You right negative does not give fragment, I have to use positive mode. And
yes the sensitivity to different compounds are different. I just wanted to
see if the instrument works fine and if there is contamination through the
line. I have checked the needle the position I thought it should be ok with
the flow rate 0.25 mL/min....spray area is about the right position to the
orifice. I will move it away try to see if there is a difference. I never
run these two compounds before so d

【在 S***x 的大作中提到】

: 就怕negative没有碎片
:
: mode

b*r2010-07-10 07:07

32 楼

It is likely due to methanol contact with the silicon or other plastic
backing of the lid. Try to run LC-MS/MS with the injection without the lid
and see if you see less noise.

S*x2010-07-10 07:07

33 楼

Right,you can run auto tune first. Then adjust by FIA.
Few weeks before, I use auto tune for a compound. The baseline is 10000 high
.....
So I have to increase both DP and CE a lot. Finally I have a reasonable
background.

And
with
I

【在 m******k 的大作中提到】

: Thanks a lot!
: You right negative does not give fragment, I have to use positive mode. And
: yes the sensitivity to different compounds are different. I just wanted to
: see if the instrument works fine and if there is contamination through the
: line. I have checked the needle the position I thought it should be ok with
: the flow rate 0.25 mL/min....spray area is about the right position to the
: orifice. I will move it away try to see if there is a difference. I never
: run these two compounds before so d

m*k2010-07-10 07:07

34 楼

OK! Really! I never had a problem with auto tune until these two compounds..
..I have a ref I tried the parameters people reported in that paper but didn
't work either....I will do it ASAP.
Thanks a lot!

high

【在 S***x 的大作中提到】

: Right,you can run auto tune first. Then adjust by FIA.
: Few weeks before, I use auto tune for a compound. The baseline is 10000 high
: .....
: So I have to increase both DP and CE a lot. Finally I have a reasonable
: background.
:
: And
: with
: I

m*k2010-07-10 07:07

35 楼

Thanks...Trying.

【在 b*****r 的大作中提到】

: It is likely due to methanol contact with the silicon or other plastic
: backing of the lid. Try to run LC-MS/MS with the injection without the lid
: and see if you see less noise.