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Topic: ESI-MS spectrum and calculating MW  (Read 3195 times)

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Offline LidaOliver

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ESI-MS spectrum and calculating MW
« on: October 24, 2012, 11:34:53 PM »
The answer is located below the spectrum, however I do not understand how it was obtained. The numbers from left to right read: 1101.5,1193.1,1301.4,1310.5,1431.6,1441.3,1590.6,1601.4,1789.2,1801.3,2044.6,2049.7
They are also labeled with A and a number, what are those referring to?
The x axis is m/z which I know is mass:charge ratio, and the y axis is the %. Where do I begin? Did they use 1301.4 as the m/z because it is the thickest line/peak? And how do I find the charge?

Offline discodermolide

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Re: ESI-MS spectrum and calculating MW
« Reply #1 on: October 24, 2012, 11:41:02 PM »
Here is a nice description of the process:
http://www.ionsource.com/tutorial/spectut/spec1.htm
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Offline LidaOliver

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Re: ESI-MS spectrum and calculating MW
« Reply #2 on: October 25, 2012, 12:33:38 PM »
Wow, that site helps clarify A LOT. So, when you use the spectrum to find the mass, choose two peaks that directly follow one another and also either double or half each other. Is this why in the answer they chose 1301.4 and 1193.1 (peaks 2 and 3) to estimate the mass?

Offline LidaOliver

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Re: ESI-MS spectrum and calculating MW
« Reply #3 on: October 26, 2012, 11:51:18 AM »
Is it correct to choose two consecutive peaks where the taller peak roughly doubles the shorter to estimate the mass?

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