Ion Mobility Spectrometry Dynamic Range Extension
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Solution Overview
Problem
Conventional ion-mobility spectrometry (IMS) and IMS-mass spectrometry (IMS-MS) instruments have a limited dynamic range, which restricts their ability to analyze various ion concentrations simultaneously due to electronic, chemical, or digitization noise, and saturation issues, limiting the detection of both low and high ion abundances.
Innovation Solution
The method involves accumulating ions over different time intervals and combining the data points from these intervals to create an accumulation frame, using an ion source, ion trap, detector, and processor to extend the dynamic range by capturing ions within the useful detection range, thereby enhancing the instrument's ability to analyze a broader range of ion concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional ion detection is used with fixed accumulation time, then the instrument structure remains simple, but the dynamic range is limited due to saturation at high ion concentrations and noise at low ion concentrations
Solution Approach 1:
The accumulation time is divided into multiple discrete time intervals (first time interval, second time interval, etc.), with each interval optimized for different ion concentration ranges. Low concentration ions are accumulated over longer periods while high concentration ions are captured in shorter intervals, allowing the system to detect across a broader dynamic range without requiring complex hardware modifications.
Solution Approach 2:
The accumulation time is made dynamic rather than fixed, allowing the system to adjust the accumulation duration based on the ion concentration being measured. The processor selectively combines data from multiple accumulation intervals with different time lengths, enabling the instrument to adapt to varying ion abundances and extend the effective dynamic range.
2Measurement precision
If longer accumulation time is used to detect low ion concentrations, then detection sensitivity improves, but high ion concentrations cause saturation and lose linearity
Solution Approach 1:
The measurement process is segmented into multiple accumulation intervals of different durations. Short accumulation intervals are used for high ion concentrations to prevent saturation and maintain linearity, while long accumulation intervals are used for low ion concentrations to enhance detection sensitivity. The processor selectively combines results from these segmented measurements.
Solution Approach 2:
The accumulation time parameter is changed across multiple measurement intervals rather than remaining constant. By varying the accumulation time parameter to match the ion concentration level, the system achieves both high sensitivity for low concentrations and high linearity for high concentrations, then combines these measurements to extend the overall dynamic range.
3Reliability
If shorter accumulation time is used to maintain linearity for high ion concentrations, then saturation is avoided, but detection sensitivity for low ion concentrations decreases
Solution Approach 1:
The detection process is segmented into multiple time intervals, with short intervals dedicated to capturing high ion concentrations while maintaining linearity, and long intervals dedicated to detecting low ion concentrations with high sensitivity. The processor combines these segmented measurements to achieve both linearity and sensitivity across the full dynamic range.
Solution Approach 2:
The accumulation time is dynamically adjusted based on the ion concentration being measured. The system uses short accumulation times when high ion concentrations are present to maintain linearity, and switches to long accumulation times when low ion concentrations are detected to improve sensitivity, with the processor selectively combining these dynamic measurements.
4Quantity of substance
If multiple accumulation intervals with different time lengths are used, then dynamic range is extended, but data processing complexity increases
Solution Approach 1:
The processor implements a feedback mechanism that selectively combines data from multiple accumulation intervals based on ion concentration levels. The system analyzes the detected ion signals and determines which accumulation interval data to combine, using feedback control to optimize the combination process and manage data processing complexity while extending the dynamic range.
Solution Approach 2:
The processor changes the data combination parameter based on the ion concentration range detected in each accumulation interval. By adjusting which intervals to combine and how to weight their contributions, the system manages data processing complexity while achieving extended dynamic range coverage.
Data Source
AI summary
A method is provided increasing the useful dynamic range of an ion mobility spectrometry (IMS) or an IMS-mass spectrometry (IMS-MS) device. The method includes accumulating a first sample of ions over a first time interval; providing the first sample of ions to an ion detector to provide a first frame, accumulating a second sample of ions over a second time interval, where the second time interval is different than the first time interval, and providing the second sample of ions to the ion detector to provide a second frame. First data points of the first frame are selectively combined with second data points of the second frame to provide an accumulation frame of the first and second samples of ions.