How can I identify the molecular fomula, based on an m/z of 350.7897?

In summary, to identify the molecular formula based on an m/z of 350.7897, one can use the mass spectrometry data to determine the exact mass of the molecule. By analyzing the m/z ratio, researchers can infer the possible elemental composition and structure by comparing it against known molecular weights and using tools like isotopic patterns, fragmentation patterns, and databases. Additionally, software tools may assist in predicting likely molecular formulas based on the given m/z value.
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Thread moved from the technical forums to the schoolwork forums
TL;DR Summary: I have the aforementioned m/z and a mass spec graph, my lecturer completely glossed over how to find the molecular formula so I'm stumped.

I have a mass spec with 4 peaks and the m/z value, how can I find the molecular formula.
 
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1000029274.jpg
 
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Maybe this can help you

 
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You have a very exact mass. Use www.chemcalc.org to find possible structures. Remember the nitrogen rule. Deduce possible structures and look if their fragmentation patterns fit the other m/z tops.
 
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What do you think the highest mass ion represents (in most examples for students to solve, that is).
What do you think the difference between two peaks represents?
What group of atoms could that be?
Repeat for several of the fragment losses.
Build the molecule.
 
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FAQ: How can I identify the molecular fomula, based on an m/z of 350.7897?

What does m/z mean in mass spectrometry?

m/z stands for mass-to-charge ratio, which is a key measurement in mass spectrometry. It represents the mass of an ion divided by its charge. For example, an ion with a mass of 350.7897 and a charge of +1 would have an m/z of 350.7897.

How can I determine the molecular formula from an m/z value?

To determine the molecular formula from an m/z value, you need to consider the possible elemental compositions that could correspond to that mass. This often involves using the m/z value to calculate the number of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and other atoms that can fit within that mass while considering the common isotopes and their abundances.

What tools or software can assist in identifying molecular formulas from m/z values?

There are several tools and software programs available for identifying molecular formulas from m/z values. These include databases like PubChem, ChemSpider, and software like MassLynx, and ChemCalc. These tools allow users to input the m/z value and search for potential molecular formulas that match.

Are there limitations to determining molecular formulas from m/z values?

Yes, there are limitations. The m/z value alone does not provide information about the structure or connectivity of atoms within the molecule. Additionally, multiple molecular formulas can correspond to the same m/z value due to isotopes or structural isomers, making it challenging to pinpoint the exact compound without further analysis.

What additional data can help confirm the molecular formula derived from an m/z value?

Additional data that can help confirm the molecular formula includes fragmentation patterns observed in tandem mass spectrometry (MS/MS), elemental analysis, and spectroscopic data such as NMR or IR. These techniques can provide insights into the structure and functional groups present in the molecule, aiding in accurate identification.

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