Time-of-flight mass spectrometer with accumulating electron impact ion source

摘要

An accumulating ion source for a mass spectrometer that includes a sample injector (328) introducing sample vapors into an ionization space (115) and an electron emitter (102) emitting a continuous electron beam (104) into the ionization space (115) to generate analyte ions. The accumulating ion source further includes first and second electrodes (108a, 108b) arranged spaced apart in the ionization space (115) for accumulating analyte ions substantially therebetween. The first and second electrodes (108a, 108b) receive periodic extraction energy potentials to accelerate packets of analyte ions from the ionization space (115) along a first axis. An orthogonal accelerator (140) receives the packets of analyte ions along the first axis and periodically accelerates the packets of analyte ions along a second axis substantially orthogonal to the first axis. A time delay between the extraction acceleration and the acceleration of each respective packet of analyte ions provides a proportional mass range of the respective packet of analyte ions.

主权项

1. An ion source for a time-of-flight mass spectrometer, the ion source comprising:
a sample injector introducing sample vapors into an ionization space; an electron emitter providing a continuous electron beam into the ionization space to generate one or more packets of analyte ions; and
an orthogonal accelerator receiving the packets of analyte ions along a the first axis and periodically accelerating the packets of analyte ions along a second axis that is substantially orthogonal to the first axis;wherein for the purpose of enhancing sensitivity and resolution, first and second electrodes arranged spaced apart in the ionization space for accumulating analyte ions within the electron beam, the first and second electrodes receiving periodic extraction pulsed potentials to accelerate packets of analyte ions from the ionization space along the first axis; andwherein a time delay between the extraction of each packet of analyte ions along the first axis and the acceleration of each respective packet of analyte ions along the second axis is generally proportional to the square root of a median mass to charge ratio of orthogonally accelerated ion packets.