A mass spectrometry (MS) apparatus is provided. The MS apparatus includes a mass spectrometer, an ionization source coupled to the mass spectrometer, and a flow injection system (FIS) coupled to the ionization source. The ionization source is configured to provide an ionized gas flow of an analyte towards an entrance of the mass spectrometer. The ionization source is further configured to provide a second gas flow of a second gas. The MS apparatus is configured to measure a mass spectrometer (MS) signal of the analyte. The MS apparatus is further configured to analyze a dependency of the MS signal of the analyte versus a parameter of the second gas flow or a state of the second gas flow and to determine a condition of the apparatus based on the analyzed dependency.