Characteristics of a volcano field ionization source mass spectrometer operating at 30 kV accelerating voltage

A volcano ionization source has been coupled to an E x B velocity filter type mass spectrometer. The principal advantages of this instrument are its high efficiency, measured at 10(-5) ions per molecule for toluene (m/z 92), and long source lifetimes of over 200 h. The mass spectrometer is designed primarily to obtain mass profiles from multicomponent samples. These profiles are obtained from untreated urine and blood serum (1 microliter and 0.25 microliter samples), then measured between m/z 50 and 400, and are finally analyzed by computer.