Modern magnetic sector mass spectrometers like the JEOL GCmate and MStation are fully automated. This means that a low-resolution calibration can be stable for periods of several months to a year. Relatively short ion source residence times and ion flight times in a magnetic sector mass spectrometer severely limit the interactions of ions with neutral molecules and other ions. Magnetic sector mass spectrometers are the method of choice for quantitative analysis by mass spectrometry. All JEOL magnetic sector mass spectrometers can provide high resolution mass spectra.
High resolution is important to separate and identify closely spaced masses.
Accurate mass measurements to determine elemental compositions are virtually always performed in high-resolution mode to avoid overlapping masses and to improve the accuracy of peak assignment. Accurate mass measurements are an invaluable tool in interpreting mass spectra and confirming elemental compositions. These can provide structural information and selectivity even in the presence of chemical interferences. Improved selectivity can be obtained by combining a double focusing mass spectrometer with additional mass analyzers to make a tandem or hybrid mass spectrometer.