November 29, 2021, 03:52:33 AM
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Topic: Cl Mass Spec exercise  (Read 135 times)

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Offline Simo

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Cl Mass Spec exercise
« on: November 25, 2021, 01:30:06 AM »
Good morning guys! Is there any good soul who can please help me understand this exercise so I can start sleep again at night?  ;)

Exercise 5 : A sample of chlorine atoms was placed in a mass spectrometer. In this sample of chlorine,
75% of the atoms were 35Cl atoms and 25% were 37Cl atoms.
The mass spectrometer detected only Cl+ ions and Cl+2 ions. The spectrum
obtained contained four peaks. Draw the mass spectrum obtained.

To my understanding, there either should be 2 columns for the chlorine isotopes ions 35 and 37, or 5 columns if they also detected the molecular ions m/c 70, 71, 72, but they don't say so.
Unless they expect me to draw a different column for the ions +2, due to their difference in mass for the loss of an extra electron, which it sounds very improbable to me.
Long story short, it doesn't make sense to me.

Please heeeeelp!

Thanks everyone and have a lekker day!!

Offline Orcio_Dojek

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Re: Cl Mass Spec exercise
« Reply #1 on: November 25, 2021, 02:30:52 AM »
Did you read about MS spectrum ? It is a graph of relative abundance vs m/z (mass to charge ratio).

Thus mixture of Cl35 and Cl37 (Cl+ and Cl2+) will give four peaks in total.

Offline scanjo

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Re: Cl Mass Spec exercise
« Reply #2 on: Yesterday at 04:44:45 PM »

Offline Orcio_Dojek

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Re: Cl Mass Spec exercise
« Reply #3 on: Yesterday at 05:26:02 PM »
But he placed a mixture of Cl35 and Cl37 atoms, not a Cl2 gas.

Even if they recombined the spectrometer detected only Cl+ and Cl2+.
« Last Edit: Yesterday at 05:45:26 PM by Orcio_Dojek »

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