it does one thing and it does it well

This app is an imitation of a program, also called iMass (but v.1.1), that was available a couple of years ago, written by Urs Roethlisberger. In the earlier version, there was a powerful and effective subroutine that displayed the isotopic envelope in a graphic form, and that included the ability to scale the spectrum up and down (or spread it out) so that details were visible. The effectiveness of that earlier program was amazing at helping those new to mass spectra to really understand the nature of isotopic envelopes generated in the mass spectra of chemical entities, especially complexes containing metals. This program displays the isotopic envelope, but as a bar chart, non-scalable and not in peak form. High resolution mass spectrometers generate peak information, not bar charts, making this less effective at engendering recognition of the relationship between observed and calculated spectra.There is a small bonus in this version. The program provides a table of peak positions and intensities for the entire isotopic envelope, which the former program did not provide, and that is a helpful addition. Missing is the ability to identify the additive (proton, sodium+, etc) that might have been used to generate the mass spectrum--and to show the effect on the observed spectrum, and also missing is the ability to show the effects of multiple charges on the resulting spectrum (M 2+ as opposed to M +, for example). Not bad and certainly of some use to those who work with mass spectrometers, but lacking some critical features in comparison to the former version.

A key feature that this app is missing is the ability to create abbreviations for molecules, molecular fragments, and complex ions, e.g. Me for CH3, Et for C2H5, etc. With this feature, a laboratory chemist such as myself can quickly obtain the molecular formula of large and complicated organic and inorganic compounds. Without this feature, I probably won't ever use this app.