A new feature has been added to the MolPrime⁺ app’s property calculation panel: the calculation of an isotopic mass distribution for the structure, which can be used to help interpret mass spectroscopy results.

As a former synthetic chemist, I spent plenty of quality time with a calculator, adding up the isotopic masses for the base peak of the compound that I hoped that I had successfully made, and for any possible fragments, and likely byproducts. Even then (in the ’90s) it wasn’t too hard to acquire software to plot a mass distribution given the formula, but life has gotten simpler: if you have drawn or otherwise loaded the structure onto your device with MolPrime+, you can get not only the formula, but the isotopic distribution and the accurate mass of the base peak, just with a couple of taps.

The dual snapshot to the top-right shows this feature in action. The distribution is calculated for one of the organometallic compounds that I made during my Ph.D. research, which shows off the feature well: having osmium at its core and a chlorine to go with it, there are plenty of naturally occurring isotopes to deal with. You may also notice that in this picture, the two triphenylphosphine ligands are represented as inline abbreviations: these are expanded out automatically. As another nicety, it is also possible to specify explicit isotopes using the sketcher (e.g. ²H or ¹³C), and these are honoured by the mass distribution calculator.

The latest version is currently awaiting review on the AppStore, and should be available within a week or so.