Dual-Gate Ion Mobility Spectrometer for Mass Analysis
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Solution Overview
Problem
The challenge lies in coupling orthogonal analytical methods like low-field and high-field ion mobility spectrometry and mass spectrometry effectively, as their differing timescales often result in loss of resolution and inability to perform meaningful separations and characterizations, particularly in high-pressure IMS systems which lack fragmentation information.
Innovation Solution
A dual-gate low-field ion mobility spectrometer operating at atmospheric or higher pressure, with two gates that work in tandem to select ion populations based on drift times, allowing for the integration with high-field ion mobility spectrometry and mass spectrometry, enabling the selection and analysis of mobility-selected ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If low-field ion mobility spectrometry is coupled with high-field ion mobility spectrometry, then separation capability is improved, but resolution is lost due to timescale discrepancies
Solution Approach 1:
The patent divides the ion mobility analysis into two distinct segments: a low-field ion mobility spectrometer for rapid separation and a high-field ion mobility spectrometer for detailed characterization. The low-field instrument performs quick initial separations, while the high-field instrument provides high-resolution analysis of selected ion populations, thereby maintaining both versatility and resolution through functional segmentation.
Solution Approach 2:
The low-field ion mobility spectrometer performs preliminary separation of ion populations before they enter the high-field instrument. This preliminary action filters and pre-sorts the ions, allowing the high-field instrument to focus on detailed analysis of specific mobility-selected populations, thus preserving resolution while maintaining separation capability.
2Measurement precision
If high-field ion mobility spectrometry is used, then separation based on size-to-charge ratio is improved, but analysis time increases
Solution Approach 1:
The analysis process is segmented into two stages: rapid low-field separation that quickly identifies ion populations of interest, followed by slower but more precise high-field analysis. This segmentation allows the system to minimize overall analysis time by performing only necessary high-resolution measurements on pre-selected ions, rather than analyzing all ions at high resolution.
Solution Approach 2:
The low-field instrument performs a partial separation that is sufficient to identify and select specific ion populations, without completing the full high-resolution separation. This partial action reduces the time spent in the slower high-field instrument, optimizing the balance between separation precision and analysis time.
3Quantity of substance
If multiple low-field IMS scans are performed, then data collection on low-abundance analytes is improved, but instrument coupling complexity increases
Solution Approach 1:
The patent introduces an ion trap as an intermediary component between the low-field and high-field instruments. The ion trap accumulates ions from multiple low-field scans and transfers them to the high-field instrument for analysis. This intermediary simplifies the coupling by providing a buffer that decouples the timing and operational cycles of the two instruments, reducing overall system complexity while enabling detection of low-abundance analytes through accumulated signals.
4Quantity of substance
If ion populations are accumulated in an ion trap, then sensitivity for low-abundance analytes is improved, but analysis time increases
Solution Approach 1:
The ion trap performs preliminary accumulation of ions from multiple low-field scans before transferring them to the high-field instrument for analysis. This preliminary accumulation increases the quantity of ions available for detection, improving sensitivity for low-abundance analytes. The accumulation time is optimized by only collecting ions that have been pre-selected by the low-field instrument, reducing unnecessary waiting time.
Solution Approach 2:
The system performs partial accumulation by selecting and accumulating only specific ion populations identified by the low-field instrument, rather than accumulating all ions. This partial accumulation reduces the total accumulation time needed while still achieving sufficient sensitivity for the analytes of interest, optimizing the balance between detection capability and analysis time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the effective mating of fast and slow analytical methods, enhancing resolution and allowing for the collection of MSn data on low-abundance analytes, improving the ability to distinguish isomeric species and provide conformational information for biomolecules.
Implementation Method 1
IMS separates gas phase ions based upon their differential migration through a weak homogeneous electric field
Implementation Method 2
the ions are separated on their interaction in a rapidly switched high and low electric field. In high-field IMS, the ions are pneumatically moved through a switching electric field which is orthogonal to the pneumatic flow
Implementation Method 3
analyzing the accumulated mobility-selected ions by mass spectrometry
Data Source
AI summary
Particular aspects provide novel methods for analysis of ion populations, the methods comprising filtering and selecting an ion population using a low-field dual-gate ion mobility spectrometer comprising a drift tube, the spectrometer operating at a pressure of at least 100 Torr, to provide mobility-selected ions. Certain aspects comprise: (i) subsequently accumulating the low-field selected ions in an ion trap (e.g., an MS ion trap) and mass spectrometry analysis; (ii) introducing the low-field selected ions into a high-field ion mobility spectrometer for separating thereby (optionally followed by mass spectrometry); and (iii) introducing the low-field selected ions into an ion trap mass spectrometer, and subsequently into a second low-field ion mobility spectrometer (e.g., a non-dual gate spectrometer operating at less than about 100 Torr). Additional aspects provide novel apparatus and combination thereof for performing the disclosed methods.