A method of automatically performing a routine to check the operational state of a mass spectrometer is disclosed wherein the method is performed automatically as a start-up routine upon switching ON the mass spectrometer. The method comprises automatically generating a vacuum within one or more vacuum chambers of a mass spectrometer and automatically generating first ions using an internal ion source, wherein the internal ion source is located within a vacuum chamber of the mass spectrometer or is located within a chamber downstream from an atmospheric pressure interface, and detecting at least some of the first ions or second ions derived from the first ions. The method further comprises automatically determining whether or not the mass spectrometer is in a correct operational state.