Ion Accumulation Region Switching for Sharper Mobility Separation
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Solution Overview
Problem
Current ion mobility spectrometry (IMS) and mass spectrometry (MS) systems face limitations in ion resolution and sensitivity due to space charge effects and broad peaks resulting from traveling wave separation, particularly over long distances, which restrict the number of ions that can be accumulated and analyzed.
Innovation Solution
The implementation of an apparatus with distinct regions for ion accumulation, featuring a drive potential and electric fields that switch between trap and release states, allowing ions to be trapped, accumulated, and then separated based on mobility using traveling waves and DC potentials, thereby overcoming space charge limitations and enhancing resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traveling wave separation is used for ion mobility separation, then ions can be separated based on mobility, but broad peaks are produced particularly over long distances
Solution Approach 1:
The device is divided into distinct functional regions: a first region for ion accumulation and a second region for ion mobility separation. This segmentation allows the accumulation region to collect ions without the broadening effects that occur in continuous separation, while the separation region maintains high resolution. The spatial division resolves the contradiction by decoupling the accumulation function from the separation function.
Solution Approach 2:
Ions are accumulated in the first region before being introduced into the separation region. This preliminary accumulation action ensures that sufficient ions are collected to achieve good signal-to-noise ratios, while the subsequent separation in the second region maintains sharp peaks. The preliminary accumulation prevents the need for long continuous separation paths that would otherwise cause peak broadening.
2Quantity of substance
If ion traps are used to accumulate ions, then the number of ions can be increased, but space charge effects limit the accumulation capacity
Solution Approach 1:
The harmful space charge effects are extracted and isolated to the first accumulation region, which is physically separated from the second separation region. By taking out the accumulation function into a dedicated region, the harmful effects of high ion density are confined to that region and do not propagate into the separation region, maintaining separation quality while enabling high ion accumulation.
Solution Approach 2:
The first region acts as an intermediary between the ion source and the separation region. It serves as a buffer that accumulates ions and manages space charge effects, then releases them in a controlled manner into the second region for separation. This intermediary region mediates between the need for high ion accumulation and the need to avoid space charge degradation.
3Quantity of substance
If the path length is increased to address space charge limitations, then more ions can be accumulated, but the device becomes larger and more complex
Solution Approach 1:
Instead of increasing path length in one dimension to achieve more accumulation, the invention uses a two-dimensional functional arrangement with distinct first and second regions. This dimensional reorganization allows high ion capacity in the accumulation region while keeping the separation region compact, avoiding the need for long continuous paths that would increase overall device complexity.
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 significantly increases the resolution and sensitivity of IMS and MS systems by effectively managing ion accumulation and separation, allowing for a higher number of ions to be analyzed without space charge issues, leading to sharper peaks and improved signal-to-noise ratios.
Implementation Method 1
generate a first drive potential configured to guide the ions across the first region in a first direction
Implementation Method 2
IMS is a technique for separating and identifying ions in the gaseous phase based on their mobilities
Implementation Method 3
generate a first electric field when in the first state... The first electric field is configured to prevent the ions from moving in the first direction
Implementation Method 4
generate a second electric field when in the second state... the second electric field is configured to guide the ions in the first direction toward a third region
Implementation Method 5
An ion having a larger mobility (or smaller collision cross section [CCS]) moves faster under the influence of the electric field
Implementation Method 6
SLIM devices can use traveling wave separation as one technique to separate ions of different mobilities
Implementation Method 7
IMS can be employed to separate structural isomers and macromolecules that have different mobilities
Data Source
AI summary
Methods and apparatus for ion accumulation are disclosed. An apparatus for ion accumulation includes multiple regions. A first region receives and transfers ions to a second region using a first drive potential. The second region is switchable between a first state where it generates a first electric field preventing ions from further movement and entering a third region, and a second state where it generates a second electric field that guides the ions toward the third region. When in the first state, the ions are prevented from further movement by the first electric field, which causes the ions to accumulate in the second region. When in the second state, the ions are moved from the second region to the third region by the second electric field. A method of accumulating ions involves switching an electric field applied to a region between a trap state and a release state.