The deflection imparted by the magnetic field, often combined with the time it takes for the molecule to reach a detector, is then used to calculate the mass of the molecule. Often in the course of sample ionization large molecules break apart, and the resulting data show a parent mass and a number of smaller fragment masses; such fragmentation can give rich insight into the sequence of proteins and nucleic acid polymers. In addition to the mass of a molecule and its fragments, the distribution of isotopic variant masses can also be determined and the qualitative presence of certain elements identified due to their characteristic natural isotope distribution.
The process of determining molecular weight involves measuring the deflection caused by a magnetic field and the time it takes for a molecule to reach a detector. As molecules are broken down during ionization, their fragments can provide valuable information about protein and nucleic acid sequences.