Indiana University

Aaron R Todd

Martin F Jarrold

Andrew W Alexander

A CDMS may include an ion source to generate ions from a sample, a mass spectrometer to separate the generated ions as a function of ion mass-to-charge ratio, an electrostatic linear ion trap (ELIT) having a charge detection cylinder disposed between first and second ion mirrors, wherein ions exiting the mass spectrometer are supplied to the ELIT, a charge generator for generating free charges, a field free region between the charge generator and the charge detection cylinder, and a processor configured to control the charge generator, with no ions in the charge detection cylinder, to generate a target number of free charges and cause the target number of free charges to travel across the field-free region and into contact with the charge detection cylinder to deposit the target number of free charges thereon and thereby calibrate or reset the charge detection cylinder to a corresponding target charge level.

Instrument, including an electrostatic linear ion trap with charge detector reset or calibration, for separating ions

A system for separating ions may include an ion source configured to generate ions from a sample, at least one ion separation instrument configured to separate the generated ions as a function of at least one molecular characteristic, and an orbitrap in which a rotating and oscillating ion induces charges on inner and outer electrode halves of the orbitrap, and wherein charge detection circuitry is configured to detect the charges induced on each of the inner electrode halves and on each of the outer electrode halves, and to combine the detected charges for each oscillation to produce a measured ion charge signal.

System for separating ions including an orbitrap for measuring ion mass and charge

A CDMS may include an ELIT having a charge detection cylinder (CD), a charge generator for generating a high frequency charge (HFC), a charge sensitive preamplifier (CP) having an input coupled to the CD and an output configured to produce a charge detection signal (CHD) in response to a charge induced on the CD, and a processor configured to (a) control the charge generator to induce an HFC on the CD, (b) control operation of the ELIT to cause a trapped ion to oscillate back and forth through the CD each time inducing a charge thereon, and (c) process CHD to (i) determine a gain factor as a function of the HFC induced on the CD, and (ii) modify a magnitude of the portion of CHD resulting from the charge induced on the CD by the trapped ion passing therethrough as a function of the gain factor.

Charge detection mass spectrometer including gain drift compensation

An orbitrap may include elongated inner and outer electrodes, wherein the inner and outer electrodes each define two axially spaced apart electrode halves with a central transverse plane extending through the electrodes also passing between both sets of electrode halves, a cavity defined radially about and axially along the inner electrode between the two inner electrode halves and the two outer electrode halves, means for establishing an electric field configured to trap an ion in the cavity and to cause the trapped ion to rotate about, and oscillate axially along, the inner electrode, wherein the rotating and oscillating ion induces charges on the inner and outer electrode halves, and charge detection circuitry configured to detect the charges induced on the inner and on outer electrode halves, and to combine the detected charges for each oscillation to produce a measured ion charge signal.

Growing community of inventors

Bloomington, IN, United States of America

Aaron R Todd