Fourier Transform-Ion Mobility Linear Ion Trap Mass Spectrometer Using Frequency Encoding for Recognition of Related Compounds in a Single Acquisition

Abstract

Fourier transform-ion mobility spectrometry is implemented by coupling a 3D-printed drift tube ion mobility spectrometer, operated at atmospheric pressure, to a linear ion trap mass spectrometer. FT-IMS separations are demonstrated for tetraalkylammonium salts, explosives, fentanyls, and amphetamines. Mobility resolving powers of up to 17 are measured for the tetraalkylammonium cations. When ions are fragmented in the FT-IMS mode, the product ions maintain the frequency and amplitude relationships established during the mobility measurement. Therefore, precursors and product ion relationships can be identified through the mobility information. Using in-source activation for nonspecific fragmentation of all precursors, functional group families of precursors and product ions are identified in a single acquisition. The identity of the precursor ion is not known a priori, but the m/z values for both precursors and product ions are measured.

Ion Mobility Mass Spectrometry for the Separation and Characterization of Small Molecules

“…DTIMS based on a flexible printed circuit board can obtain high resolution (>80) at lower drift voltage (3 kV) and shorter drift length (50 mm) . Multiplexing DTIMS (Fourier transform , and Hadamard transform , ) can also significantly increase the resolution.…”

Leveraging 3D printing to enhance mass spectrometry: A review

“…A different type of ion guide, the drift tube used in ion mobility spectrometry (IMS), can similarly be 3D printed (Fig. 5D) [52,53,101]. Where in the previous example, only the funnel housing was 3D printed, here, the authors used a carbon nanotube-doped polymer for FDM printing of the electronic parts, as well as the non-conductive elements of the ion guides.…”

“…The drift tube could be used in different setups, namely for stand-alone IMS, as well as hyphenated to an MS instrument [52]. Initially it was reported that the drift tube could only be used by instruments with a fast mass analyzer (such as TOF), but coupling to a slower analyzer (such as an ion trap or Orbitrap) has also been demonstrated through the implantation of a dual-gated system [53], or by Fourier Transform IMS [101].…”

Separation and Collision Cross Section Measurements of Protein Complexes Afforded by a Modular Drift Tube Coupled to an Orbitrap Mass Spectrometer

“…Modular drift-tube systems have recently been developed and coupled to various ion trap and Orbitrap instruments. − One of the first IMS-enabled Orbitrap systems utilized ambient-pressure drift tubes to separate small isomers (<2 kDa), as demonstrated for a series of peptides, saccharides, lipids, and metabolites. , However, the incompatibility of the timescales of the IMS separation (milliseconds) and the Orbitrap mass analysis (tens of milliseconds to seconds) results in a poor duty cycle of <1%, thus wasting more than 99% of ions that are generated using an ESI source. The design of Fourier transform (FT)-based multiplexing strategies, originally implemented on quadrupole ion trap and linear ion trap systems, involves controlled frequency modulation of a dual-gate pulsing scheme of a drift tube, increasing the duty cycle to 25%. ,,− This type of FT multiplexing offers an innovative approach to overcome the duty-cycle mismatch and establishes the framework for the development of FT-IMS-Orbitrap platforms. Advancements have also been made in data collection and processing to improve the throughput, resolution, and sensitivity of FT methods, including the adoption of basis pursuit denoising and absorption-mode FT .…”