[Plumbum]

hey guys

In really having problems with this easy mass spectrometrie thing one here.

Have no idea how to distinguish them as they have the exact total mass !! please pleas help me

[Arkcon]

So, you have two samples, that give the same m/z and the same fragments, but different intensities.  Hmmm ... tricky.  Maybe the only difference between the two samples has more to do with the acquisition parameters than the sample?

[orgopete]

More info missing?

MW 128, MFs C7H12O2, C8H16O, or C9H20? Now, how many structures could we write for each of them?

I could guess some fragments present from the MS. I just don't know that I could know the answer to the question though.

[kriggy]

Do you have more detailed spectra? Or exact intensities of your peaks? You could calculate the amount of carbon atoms in your molecule from the intensity of your molecular peak and its isotopic peak: 100*%¹³C / %¹²C and then you divide the number by 1,1 and you get the amount of carbons in your molecule.

From the spectrum I suppose its some hydrocarbon, possibly nonane or some of its isomers. Especialy the 1st one looks like nonane since the spectrum looks quite periodical. The second one maybe 3-ethylheptane? From the increased intensity of 57 and 99 and very low of 85?