Trapping Ion Mobility Analyzer with Non-Constant Field Gradient

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Solution Overview

Problem

Current ion mobility spectrometers face challenges in achieving high mobility resolution while maintaining a compact size, as they require long drift regions and high electric field strengths, leading to ion losses and limited utilization rates, especially when analyzing complex samples in bottom-up proteomics.

Innovation Solution

An ion mobility analyzer with a non-constant electric field gradient along the rising or falling edge, where the slope of the electric field strength is adjusted to trap ions effectively, combined with a radially confining RF field and controlled gas flow, allows for increased accumulation time and reduced ion losses, enhancing the duty cycle and mobility resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If long drift regions and high electric field strengths are used to achieve high mobility resolution, then mobility resolution is improved, but device length and ion losses increase

Engineering Contradiction:
Improvemobility resolutionVSAvoiddrift region length
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent applies a dynamic, non-constant electric field gradient along the drift region where the field strength varies continuously rather than being uniform. This dynamic field configuration allows ions to be accelerated and decelerated strategically, achieving high mobility resolution in a compact drift region while minimizing ion losses that would occur in traditional long uniform field configurations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the electric field parameter from a constant value to a spatially varying gradient. By optimizing the field strength distribution along the drift path, the system achieves enhanced mobility separation efficiency per unit length, thereby reducing the required drift region length while maintaining or improving mobility resolution

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If long drift regions are used to achieve high mobility resolution, then mobility resolution is improved, but ion losses increase

Engineering Contradiction:
Improvemobility resolutionVSAvoidion losses
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The dynamic electric field gradient allows for strategic acceleration and deceleration of ions throughout the drift region. Ions are accelerated in regions where separation is needed and decelerated where separation is complete, preventing excessive ion losses that would occur in long uniform field configurations while achieving the required mobility resolution

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The optimized electric field gradient enables ions to be rapidly separated in critical regions and then quickly transmitted through the remaining drift path with minimal interaction time, reducing the opportunity for diffusion and ion losses while achieving high mobility resolution

Inventive Principle:
Principle #21Skipping (Rushing through)

3Measurement precision

If high electric field strengths are applied to improve mobility resolution, then mobility resolution is improved, but ion losses and limited utilization rates increase

Engineering Contradiction:
Improvemobility resolutionVSAvoidion losses
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent optimizes the electric field strength distribution by implementing a spatial gradient rather than using uniformly high field strengths. This allows high field regions to be concentrated where maximum separation power is needed while using lower field strengths in other regions, thereby achieving high mobility resolution with reduced overall ion losses and improved ion utilization rates

Inventive Principle:
Principle #35Parameter changes

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 utilization rate of ions from the ion source, allowing for higher mobility resolutions and efficient analysis of complex samples, particularly in bottom-up proteomics, by minimizing radial ion losses and optimizing ion trapping and detection.

Implementation Method 1

an RF field for radially confining ions along an axis

Methodology Applied
Scientific EffectRF field confinement: Electromagnetic Induction

Implementation Method 2

a region with an axial electric DC field and a gas flow along the axis counteracting the electric DC field

Methodology Applied
Scientific EffectGas flow transport: Convection

Implementation Method 3

the slope of the electric field strength along the axis is not constant at a substantial portion of the edge... allowing for increased accumulation time and reduced ion losses

Methodology Applied
Scientific EffectElectric field trapping: Electric Field

Implementation Method 4

The mobility of ions can be measured via their drift velocities in a gas under the influence of an electric field... separate their ions according to their different mobilities

Methodology Applied
Scientific EffectIon mobility separation: Electrophoresis

Data Source

PatentEP3054475B1High duty cycle trapping ion mobility spectrometer
Publication Date: 2020.03.04 BRUKER DALTONIK GMBH
  • EP3054475B1 patent drawingFigure 1
  • EP3054475B1 patent drawingFigure 2
  • EP3054475B1 patent drawingFigure 3~4

AI summary

The invention provides a trapping ion mobility analyzer and methods for operating the ion mobility analyzer. The trapping ion mobility analyzer comprises an RF field for radially confining ions along an axis, a region with an axial electric DC field and a gas flow along the axis counteracting the electric DC field in the region, wherein the region either comprises a rising edge with an increasing axial electric DC field or a falling edge with a decreasing axial electric DC field and wherein the slope of the electric field strength along the axis is not constant at a substantial portion of the edge.