Ion Trap RF Scan Segmentation for High-Mass Ion Detection

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Solution Overview

Problem

Current ion trap systems in mass spectrometry face limitations in mass range and suffer from ion discrimination, particularly in high Thompson value ranges, leading to reduced detection rates of ions.

Innovation Solution

A multi-directional segmented scan approach is employed, where the ion trap performs a first scan by increasing the main RF voltage and a second scan by decreasing it, allowing for extended mass range analysis without compromising lower range mass/charge efficiency and reducing mass discrimination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a continuous scan is performed across a wide Thompson value range, then the mass range coverage is improved, but ion discrimination increases and detection rate of high Thompson value ions decreases

Engineering Contradiction:
Improvemass range coverageVSAvoidion detection rate
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The continuous mass scan is divided into multiple discrete scan steps across different Thompson value ranges. Each scan step targets a specific mass range with optimized ejection parameters, allowing the system to cover a wide overall mass range while maintaining high detection rates for ions in each segment without the discrimination problems of a single continuous scan.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the mass range of the ion trap is extended to high Thompson values, then high mass analysis capability is improved, but lower range mass/charge efficiency is compromised

Engineering Contradiction:
Improvehigh mass analysis capabilityVSAvoidlower range mass/charge efficiency
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

Different ejection parameters are applied to different mass ranges. For each scan step targeting a specific Thompson value range, the ejection parameters are locally optimized to match that range's characteristics. This allows high mass ions to be analyzed with appropriate parameters while lower mass ions in other scan steps receive optimized parameters for their specific range, preventing the efficiency loss that would occur with a single set of parameters for the entire mass range.

Inventive Principle:
Principle #3Local quality

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 method enhances the detection of ion species across a wide range of Thompson values, improving the mass range of ion trap performance and reducing discrimination against high Thompson value species.

Implementation Method 1

Ion traps are devices that use electromagnetic fields to store charged particles, typically ions, in a vacuum chamber.

Methodology Applied
Scientific EffectRF trapping: Electromagnetic Induction

Implementation Method 2

Ion traps operate by applying radio frequency (RF) voltages to electrodes, creating time-varying electric fields that confine ions through the Mathieu equations.

Methodology Applied
Scientific EffectElectromagnetic field interaction: Lorentz Force

Implementation Method 3

The system performs frequency scans by varying the RF voltage frequency to match the secular frequency of ions with different mass-to-charge ratios, causing resonant heating and ejection of ions from the trap.

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4328954A1Two frequency ion trap AGC scanning for improved high mass range performance
Publication Date: 2024.02.28 THERMO FINNIGAN LLC
  • EP4328954A1 patent drawingFigure 1A~1B
  • EP4328954A1 patent drawingFigure 2
  • EP4328954A1 patent drawingFigure 3

AI summary

This system and method disclosed herein are configured to improve high mass range ion trap performance by use of a multi-directional segmented scan approach. In some embodiments of the system and method disclosed herein, the mass range of conventional ion trap technology may be extended/increased without changing the hardware or compromising lower range mass/charge efficiency. Specifically, the system and methods disclosed herein use a segmented, bi-directional scan that increases the mass range of an ion trap mass spectrometer and circumvents the problem of mass discrimination during mass analysis in the high Thompson value range.