Nothing more

But this are the most important information to analyse and characterise your compound.

With the development of so-called soft ionisation methods, mainly electrospray ionisation by John B. Fenn in the end 1980's, it became possible to measure non-volatile compounds, like most small molecules or peptides or proteins, to name a few, and determine their molecular mass. Electrospray ionisation made its slo possible to couple directly to chromatographic or electrophoretic separation methods to analyse complex mixtures.

The molecular mass is simply the sum of the atomic masses of all atoms in the molecule, wich can be 18 Da for water [2 x H and 1 x O] or 69,367 Da fo human serum albumin [2936 x C, 4624 x H, 786 x N, 889 x O, 41 x S]. Every molecule is determined by its molecular formula and the molecular weight can be measure using a mass spectrometer.

The analysis gets more sophisticated as state-of-the-art instruments can measure the isotopic distribution. All organic molecules are not simply composed of carbon-12, but also contain 1 % of carbon-13, a stable, non-radioactive isotope with one more neutron in the nucleus.

Measuring the exact molecular mass and the isotope distribution it became possible for small molecules to predict the formula without any other chemical analysis.

Molecules undergo gas-phase fragmentation when collided with an inner gas at evaluated energy with in the mass spectrometer. The molecular weights of these fragments can be then determined in the same instrument, giving information about the structure of the molecule. These mass spectrometers are called tandem-mass spectrometers as they have two independent separation units.
This is widely used in the analysis of recombinant proteins or in Proteomics.

For more information how mass spectrometry alone or in combination with chromatographic or electrophoretic separation can support and speed-up your projects, contact us.