Macromolecular ion accelerator mass spectrometer.

We present a newly developed macromolecular ion accelerator mass spectrometer that combines a dual-ion-trap device and a macromolecular ion accelerator (MIA) to achieve the capability of analyzing samples with a mixture of large biomolecules. MIA greatly increases detection efficiency. The dual ion trap includes a quadrupole ion trap (QIT) and a linear ion trap (LIT) in tandem. The dual ion trap is mounted ahead of the MIA. The QIT is used to store multiple species, and the LIT is employed to capture the ions that are sequentially ejected out of the QIT. Subsequent to their capture, the ions inside of the LIT are extracted and transferred to the MIA. The synchronization between the QIT and MIA is bridged by the LIT. A sample containing a mixture of several large biomolecules was employed to examine the performance of this new type of mass spectrometer. The result reveals that larger biomolecules show a comparable signal to smaller biomolecules, even though the mixture contains equal quantities of each type of protein. The overall assembly produces a nearly constant detection efficiency over a broad mass range. Thus, this device provides an alternative platform to analyze complex large-protein mixtures.

Biomolecular dual-ion-trap mass analyzer.

We developed the first dual-ion-trap mass analyzer which can detect ions with a high mass-to-charge ratio (m/z > 6000). The first ion trap is a quadrupole ion trap (QIT), which was operated by step scanning of the trapping frequency for a sample containing mixtures of biomolecules. The second ion trap, linear ion trap (LIT), was utilized to capture selected ions ejected out of the QIT so that all ions from the QIT can be examined one by one. It was found that the ions can be transferred from the QIT to the LIT with ~60% efficiency for large biomolecular ions with high m/z. This is by far the highest transfer efficiency in the dual ion trap device for high-mass ions.

Macromolecular ion accelerator.

Presented herein are the development of macromolecular ion accelerator (MIA) and the results obtained by MIA. This new instrument utilizes a consecutive series of planar electrodes for the purpose of facilitating stepwise acceleration. Matrix-assisted laser desorption/ionization (MALDI) is employed to generate singly charged macromolecular ions. A regular Z-gap microchannel plate (MCP) detector is mounted at the end of the accelerator to record the ion signals. In this work, we demonstrated the detection of ions with the mass-to-charge (m/z) ratio reaching 30,000,000. Moreover, we showed that singly charged biomolecular ions can be accelerated with the voltage approaching 1 MV, offering the evidence that macromolecular ions can possess much higher kinetic energy than ever before.