Offline mass calibration

A mass spectrometer, comprising:

• an ion source configured to form ions from one or more calibrant species and to separately form ions from a sample, the sample including a first sample ion species of known mass, the first sample ion species having a mass-to-charge ratio outside of the range of the mass-to-charge ratios of the calibrant ion species;
• a mass analyzer configured to measure a mass related physical value for an ion;
• a controller configured to:
• obtain a first set of mass related physical values for ions from the one or more calibrant species;
• obtain a second mass related physical value for the first sample ion species;
• calculate a mass calibration curve based on the first set of mass related physical values, the second mass related physical value, and known mass-to-charge ratios of the ions from the one or more calibrant species and the first sample ion species;
• and
• modify at least one instrument parameter of the mass analyzer based on the mass calibration curve.