METHOD OF SEPARATING A MAS OR NARROW-RANGING MASSES AND/OR RAISING SENSITIVITY OF ION-TRAP MASS SPECTROMETER

摘要

PURPOSE: To operate a three-dimensional ion trap at high sensitivity, by ionizing and releasing a sample in an RF electric field, and adding a pulse D.C. electric field to trap a selected mass ion. CONSTITUTION: An ionized electron beam from a filament 17 ionizes a sample atom introduced into an ion accumulated region 16 by an FR electric field. An RF voltage generator 14 and a D.C. power source 15 supply RE voltage and D.C. voltage between end caps 12 and 13 of three-dimensional ion trap 10 and a ring electrode 11, to generate a quadrupole electric field in order to trap an ion within the ion accumulating part 16; and an unstable ion in the ion trap electric field is insident into an electron doubling tube 24. The ion signal 26 is converted into voltage by an electric meter 27, to send a control signal to the RF voltage generator 14 and a filament lens controller 32 via a scanning/collecting processor 29 through an A/D convertor 28.