Electrostatic Trap Ion Injection to Reduce Peak Coalescence

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Solution Overview

Problem

Electrostatic trap mass spectrometers face challenges in achieving optimal ion cloud stability and mass spectral resolution due to ion-ion interactions, particularly peak coalescence, which affects the accuracy of mass analysis.

Innovation Solution

The method involves exploiting ion optical lens aberrations to spatially disperse ion packets upon entry into the electrostatic trap, reducing charge density and ion-ion interactions by altering the field strength of transfer lenses and applying asymmetric voltages or shifting the focal point, thereby reducing peak coalescence without compromising other mass spectral characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ions are focused into a tight packet upon entry into the electrostatic trap, then injection efficiency is improved, but ion-ion interactions increase causing peak coalescence and reduced mass spectral resolution

Engineering Contradiction:

Improveinjection efficiencyVSAvoidmass spectral resolution

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies asymmetry by intentionally introducing optical aberrations through asymmetric voltage application to transfer lenses. This creates an asymmetric ion packet distribution upon entry into the electrostatic trap, where ions are spatially dispersed rather than tightly focused. The asymmetric field configuration reduces ion-ion interactions while maintaining adequate injection efficiency, thereby resolving the contradiction between injection efficiency and mass spectral resolution.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the electrical parameters of the transfer lenses by applying asymmetric voltages that differ from the nominal symmetric operating conditions. This parameter change introduces controlled optical aberrations that spatially disperse the ion packet, reducing charge density and ion-ion interactions. The parameter modification allows the system to achieve both acceptable injection efficiency and improved mass spectral resolution by preventing peak coalescence.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If symmetric voltages are applied to transfer lenses for optimal focusing, then ion beam focus is improved, but peak coalescence occurs due to increased ion-ion interactions

Engineering Contradiction:

Improveion beam focusVSAvoidmass spectral resolution

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent applies the inversion principle by deliberately deviating from the conventional symmetric voltage application to transfer lenses. Instead of maintaining symmetric voltages for optimal focusing, the patent applies asymmetric voltages that introduce controlled optical aberrations. This inverted approach sacrifices perfect ion beam focus in exchange for spatial dispersion of ions, reducing ion-ion interactions and preventing peak coalescence, thereby improving mass spectral resolution.

Inventive Principle:

Principle #13The other way round (Inversion)

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 enhances space-charge tolerance and improves mass spectral resolution by reducing peak coalescence, maintaining isotope ratio fidelity and overall resolving power.

Implementation Method 1

transferring the first stored packet of ions into an electrostatic trap mass analyzer through a set of electrostatic lenses

Methodology Applied

Scientific EffectElectrostatic field: Electric Field

Implementation Method 2

transferring the first stored packet of ions into an electrostatic trap mass analyzer through a set of electrostatic lenses

Methodology Applied

Scientific EffectElectrostatic lens: Electrostatic Lens

Implementation Method 3

Electrostatic traps are a class of ion optical devices where moving ions experience multiple reflections or deflections in substantially electrostatic fields

Methodology Applied

Scientific EffectElectrostatic field: Electric Field

Implementation Method 4

trapping in electrostatic traps is possible only for moving ions

Methodology Applied

Scientific EffectElectrostatic trapping: Electrostatic Induction

Implementation Method 5

ions are compelled to undergo collective oscillatory motion within the analyzer that induces a correspondingly oscillatory image charge in neighboring detection electrodes

Methodology Applied

Scientific EffectElectrostatic induction: Electrostatic Induction

Data Source

PatentUS11810773B2Apparatus and methods for injecting ions into an electrostatic trap

Publication Date: 2023.11.07 THERMO FINNIGAN LLC

AI summary

A mass spectrometry method comprises: introducing a first packet of ions into an electrostatic trap mass analyzer through a set of electrostatic lenses, wherein, during the introducing of the first packet, either the lenses are operated in a first mode of operation or an injection voltage of a first pre-determined magnitude is applied to an electrode of the mass analyzer; mass analyzing the first ion packet using the mass analyzer; introducing a second packet of ions into the mass analyzer through the set of lenses, wherein, during the introducing of the second packet, either the lenses are operated in a second mode of operation or an injection voltage of a second pre-determined magnitude is applied to the electrode of the mass analyzer; and mass analyzing the second packet of ions using the electrostatic trap mass analyzer.