High Mass Ion Detection with Charge Detector Coupled to Rectilinear Ion Trap Mass Spectrometer

Abstract

Conventional linear ion trap mass analyzers (LIT-MS) provide high ion capacity and show their MS ability; however, the detection of high mass ions is still challenging because LIT-MS with secondary electron detectors (SED) cannot detect high mass ions. To detect high mass ions, we coupled a charge detector (CD) to a rectilinear ion trap mass spectrometer (RIT-MS). Immunoglobulin G ions (m/z ~150,000) are measured successfully with controlled ion kinetic energy. In addition, when mass-to-charge (m/z) ratios of singly charged ions exceed 10 kTh, the detection efficiency of CD is found to be greater than that of SED. The CD can be coupled to LIT-MS to extend the detection mass range and provide the potential to perform MS of high mass ions inside the ion trap. Graphical Abstract ᅟ.

Real-Time Monitoring of the Evaporation and Fission of Electrospray-Ionized Polystyrene Beads and Bacterial Pellets at Elevated Temperatures

“…The nondestructive approach gauges image charges as ions traverse a cylindrical charge-sensitive detector. ,,,,, This method readily discerns charges carried by nanometer- and micrometer-sized macroions [e.g., polystyrene (PS) beads, polyethylene glycol, amyloid fibrils, and viruses], typically ranging from ∼400 to ∼2000. Conversely, the destructive method employs a planar charge-sensitive device to gauge image charges upon ion impact. ,,− This method is applied to synthetic PS beads with diameters of 2–15 μm, revealing charge numbers of 1000–60,000, measured individually using a quadrupole ion trap mass analyzer …”

Development of a High-Field “Brick” Mass Spectrometer with Extended Mass Range and Capable of Characterizing Native Proteins

“…A miniature digital ion trap, driven by a square wave, could analyze ions from 650 to 70,000 Th. − Great efforts have been made to develop particle ion trap mass spectrometers driven by a sinusoidal frequency scanning technique. For example, Peng and coworkers measured the cell and microparticle mass distribution by the use of a high-voltage rf amplifier. − Nie and coworkers described a miniature ion trap mass spectrometer that could measure polystyrene spheres, silica particles, and mice red blood cells . Chen and coworkers realized the detection of biological macromolecules such as IgG and IgA by using a high-voltage rf amplifier with an output of 800 V p‑p over a scanning frequency range from 300 to 100 kHz. , These studies utilized high-voltage op-amps (e.g., PA194 or PA94) as rf amplifiers to drive ion traps, which was beneficial for detecting the mass of a large particle or biological molecule.…”