Accurate Mass to Molecular Weight Algorithm

[Chris Clark]

I am trying to reduce my data entry workload through automation of an accurate mass calculator. I have a table of accurate "mass to charge" output vs. intensity from an agilent mass spectrometer. Currently I have to key input each of these molecular weights into the "Agilent MassHunter" mass calculator and get the multiple molecular formula matches and export these matches to excel (with their deviation). Ultimately I parse these molecular formulas, count the number of each atom in the molecule and calculate "O:C", "H:C", and "N:C" ratios (the value of interest for my research. It should be noted that I expect my mass spectra to be made up of molecules with ONLY C, N, H, and O atoms, this fixes the chemistry allowed. I am looking for open source code, or an algorithm I can put in VBA-excel macros or MATLAB, that will take the accurate mass input (i.e. 297.0915 AMU), output molecular formula (i.e. C15 H13 N4 O3) and preferably output deviation (i.e. measured-calculated= -0.0073 AMU)

[Dormilich]

are you sure that your mass spectrometer is exact enough to do this calculation? eventually, the isotope pattern has to match as well.

[Rabbit]

If you can explain the math you use to calculate your results, we can explain the computer algorithm that can be used to calculate it.

[Dormilich]

I‘d say it‘s something similar to a Fourier or Waveform Anaylsis.