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yxh-5566

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[求助] 液质正模式分析一个化合物,分子量增加46 会是加了2个钠吗

如题,一个分子上能加两个钠吗
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valley_chow

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yxh-5566: 金币+1, ★★★很有帮助 2012-12-26 16:46:10
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3楼: Originally posted by lzjessie_wlf at 2012-12-21 23:56:09
The 46 difference from your single-charged compound  normally should come from the formic acid adduct  since formic acid (or TFA) is added for positive mode in ESI.

Only 22 differentiated from the ...

M+Na就直接是带电荷的离子了,没有多加一个氢了,你用22和44来打比方都是不对的,只有聚乙二醇化合物才会有+22和+44的。
8楼2012-12-24 12:33:31
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organicsuper

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crity328: 金币+1, 感谢交流,欢迎常来~ 2012-12-21 21:21:01
yxh-5566: 金币+1, ★★★很有帮助 2012-12-24 12:39:39
加2个Na也可以,但是就要出双电荷峰,即主峰跟同位素峰(也就是M+1)峰之间的间距是0.5m/z.其它的貌似没有46的分子加上去.如果可是溶剂分子,那么去问问做质谱的老师用的是啥溶剂.
2楼2012-12-21 19:06:35
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lzjessie_wlf

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yxh-5566: 金币+1, ★★★很有帮助 2012-12-24 12:39:57
The 46 difference from your single-charged compound [M+H] normally should come from the formic acid adduct [M+H+HCOOH] since formic acid (or TFA) is added for positive mode in ESI.

Only 22 differentiated from the [M+H] peak if a sodium was added, and 44 differentiated from the [M+H] peak if two sodium were added for single charged peak.
  For double charged peak, the m/z for it should be [M+Na+Na]/2 since two positive charge have been attached.
the difference between isotope pattern should be 0.5 instead of 1 for single charged peak.
3楼2012-12-21 23:56:09
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zzjcust

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yxh-5566: 金币+1, ★★★很有帮助 2012-12-24 12:40:14
要是加钠是不是带两个电荷了,质荷比就不对了,加甲酸的可能性大一些,
4楼2012-12-22 07:17:16
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