[Telamond]

I've been having some troubles solving this spectra. It's actually the first one in the exercises sheet, and doesn't come with an answer. I was hoping to get some feedback on how I'm attempting to solve it, and perhaps someone could give me some ideas on what I'm missing...

1) First thing I do is to check for any isotopic patterns from Cl and Br, none of them are there, so I discarded them.

2) I assume that m/z 101 is the M+ ion. The neutral loss from 101 to 86 is a loss of 15 which counts as a logical neutral loss m/z 15.

3) Ion series 15, 29, 43, 57 seems to be an alkane chain. From m/z 86 Int 11 and m/z 87 Int 0.4 I calculate that the numbers of carbons should be ~3 or 4.

((0.4/11)*100%)/1.1=3.3

4) If there's 4 Carbons forming an alkane series then that should cover 57 out of the 101 Da. 44 Da remains. It's probably here where I'm a bit lost and don't know what to do.

4.1) If I add two oxygen, then I will receive a remainder of 12 Da, which would be one carbon, but no hydrogen. Also, this can't be possible since counting the r+db (ring + double bonds) you receive a half integer, which would mean that 101 wasn't the M+.

4.2) Maybe an even numbers of nitrogen are present? 2 is the only amount that would fit. Remaining is 16 Da which would be an oxygen. This would result in a formula of C₅N₂OH₉, r+db=1
Working with this formula I have a hard time finding which fragment results into 59. So I'm guessing that this is wrong as well...

There has to be a more efficient way to solve spectra? Any advice?

[Arkcon]

There is a tiny program, available for both the Mac and the PC, that will take the mass of fragments, the resolution of your mass spec, and possible atoms you allow, that will then spit back the possible molecules.  It is very useful for day to day work such as yours.  I dare not post a link, because it's hosted on the authors home page, and I'd hate to see it get spammed, then get taken offline and lost to everyone.  If you search Google, for such a program, you'll find it.  Here's a picture of the web page's header -- you can see, this is real old school

[Telamond]

Thank you for the program.
It will come in handy in the future when I solve mass spectrum.
But I still need help with solving these, without the help of programs. ; ;