Methods of calibrating a mass spectrometer

A method of calibrating a mass spectrometer comprising:

• experimentally determining the mass to charge ratios of a plurality of chemical compounds in a reference standard using a mass spectrometer configured to scan ions at a first scan speed;
• experimentally determining the mass to charge ratios of said plurality of chemical compounds in said reference standard using a mass spectrometer configured to scan ions at a second scan speed;
• generating sets of data corresponding to each chemical compound, each set of data comprising the experimentally determined mass to charge ratios and the first and second scan speeds;
• interpolating from the sets of data a mass to charge ratio for each chemical compound at a scan speed different from the first and second scan speeds;
• and
• constructing a calibration curve using the mass to charge ratios interpolated from the sets of data, wherein the interpolating step is performed using probabilistic methods.