Tilted RF Multipole Ion Guide for Mass Spectrometry Noise Reduction

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Solution Overview

Problem

Existing mass spectrometry systems face challenges in efficiently transporting ions through multiple vacuum pumping stages while minimizing background particle noise, which affects signal-to-noise ratio and ion transmission efficiency due to collisions with background gas molecules and contamination from ion sources and collision cells.

Innovation Solution

A continuous RF multipole ion guide is configured with a tilted or curved axis to prevent line-of-sight between high-pressure regions and the mass analyzer detector, reducing collisions and background noise by guiding ions through vacuum partitions with minimal gas flow restriction, ensuring efficient ion transport and noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional axial ion guide is used to transport ions through vacuum stages, then ion transmission is maintained, but background particles from high-pressure regions can reach the detector creating noise

Engineering Contradiction:

Improvebackground noiseVSAvoidion guide configuration

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The ion guide is tilted at an angle relative to the mass analyzer axis, introducing a spatial dimension change that prevents background particles from traveling along straight-line paths from high-pressure regions to the detector, while still allowing ion transport through the vacuum stages

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The ion guide is divided into multiple sections with different orientations - a first section at an angle to the mass analyzer axis for preventing background particle access, and a second section that aligns ions properly for entry into the mass analyzer, segmenting the transport path to address different functional requirements

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If the ion guide is tilted to prevent background particle access, then background noise is reduced, but ion transmission efficiency may be compromised

Engineering Contradiction:

Improvebackground particle accessVSAvoidion transmission efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Electrostatic deflectors are used to dynamically steer and focus ion beams through the tilted ion guide configuration, adjusting ion trajectories in real-time to maintain high transmission efficiency despite the angled path that prevents background particle access

Inventive Principle:

Principle #15Dynamics

3Reliability

If multiple vacuum pumping stages are used to isolate the mass analyzer, then vacuum pressure is maintained, but background gas flow into the mass analyzer region occurs

Engineering Contradiction:

Improvevacuum pressure maintenanceVSAvoidbackground gas flow

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The ion guide acts as an intermediary structure that extends through the vacuum partition between pumping stages, providing a controlled pathway for ion transport while the vacuum stages maintain pressure differentials to restrict background gas flow into the mass analyzer region

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration significantly improves ion transmission efficiency and reduces background noise by preventing particles from reaching the detector, enhancing signal quality and reducing complexity and cost compared to prior art.

Implementation Method 1

A continuous RF multipole ion guide is configured with a tilted or curved axis to prevent line-of-sight between high-pressure regions and the mass analyzer detector

Methodology Applied

Scientific EffectRF electric field guidance: Electric Field

Data Source

PatentUS8723107B2Multipole ion guide interface for reduced background noise in mass spectrometry

Publication Date: 2014.05.13 PERKINELMER U S LLC

AI summary

Ions that are transported from an ion source to a mass spectrometer for mass analysis are often accompanied by background particles such as photons, neutral species, and cluster or aerosol ions which originate in the ion source. Background particles are also produced by scattering and neutralization of ions during collisions with background gas molecules in higher pressure regions with line-of-sight to the mass spectrometer detector. In either case, such background particles produce noise in mass spectra. Apparatus and methods are provided in which a multipole ion guide is configured to efficiently transport ions through multiple vacuum stages, while preventing background particles, produced both in the ion source and along the ion transport pathway, from reaching the detector, thereby improving signal-to-noise in mass spectra.