Introduction
Ion accumulation devices are routinely used to shape ion packets prior to pulsed extraction into an analyzer. A novel ion accumulation and extraction device formed of two pressure regions for parallel accumulation/fragmentation and extraction is presented. It has a unified, phase-locked RF pseudopotential channel for seamless transfer of pre-cooled analyte ions to overcome common limitations. Axial accumulation and movement are performed via DC electrodes, allowing fast processing at reduced pressures.
Methods
The design of the ion processor was optimized with sophisticated simulation software and during experimental studies. Special consideration was given to the operational speed so that an entire MS/MS cycle can be executed in under 5ms.
For performance characterization the ion processor device was coupled with the Thermo Scientific™ Astral™ analyzer. Direct infusion experiments with PierceTM FlexmixTM calibration solution and proteins were carried out to investigate key characteristics of the ion processor device including ion transfer times, space charge performance, shot-to-shot mass accuracy, fragmentation and extraction performance.
Preliminary data
Simulation results, design and experimental data of the ion processor device will be presented. We introduce an elaborate differential pumping system which enables optimal balance of ion thermalization time and gas pressure in the device's different compartments, avoiding unwanted collisional scattering during extraction to the mass analyzer.
Special emphasis will be given to the extraction region where an optimized design that increases the depth of the quasi-potential well during accumulation and improved uniformity of the acceleration field during extraction is presented.
Experimental MS and MS/MS data at high repetition rates >200Hz were collected. The ion processor utilizes a parallel operation scheme with accumulation/fragmentation in one compartment and extraction at kilovolt potential in the neighboring compartment. Fast, low energy transfer between the two compartments is performed across a seamless, lens free interface. Operation of the ion processor within a novel HRAM instrument enables parallel processing of multiple ion packages to further improve the duty cycle.
Accumulation capacities of several 105 charges per ion package and signal linearity of several thousand for single m/z have been achieved. This allows for peptide identification and quantitation at highest throughput even for short LC gradients. Feasibility to use the ion processor for intact protein analysis at high repetition rates will also be demonstrated.
Conclusion
Novel orthogonal extraction device conjoined with novel Astral analyzer for parallel lossless ion processing with analytical spectral rate >200Hz.