Ion Trap Mass Analyzer Quantitative Analysis Method

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Solution Overview

Problem

Conventional ion trap mass spectrometry methods introduce inaccuracies due to ionization process fluctuations, leading to higher relative standard deviation and uncertainty in quantitative mass analysis when analyte and internal standard ions are injected and analyzed in separate events.

Innovation Solution

The method involves concurrently isolating and fragmenting precursor ions with different mass-to-charge ratios in an ion trap mass analyzer, using resonance ejection at varying q-values to selectively eject and detect product ions, allowing for simultaneous analysis of analyte and internal standard ions from a single ion injection event, thereby minimizing ionization-related errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If analyte and internal standard ions are injected and analyzed from two time-separated ion injection events, then the ion trap mass analyzer can perform sequential analysis, but ionization process fluctuations occur between events introducing inaccuracy and increasing relative standard deviation

Engineering Contradiction:
Improvequantitative mass analysis accuracyVSAvoidmeasurement stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines the injection of analyte ions and internal standard ions into a single ion injection event, allowing both to be analyzed simultaneously in the ion trap mass analyzer. This merging eliminates the time-separated injection approach and prevents ionization process fluctuations from occurring between separate events, thereby improving measurement accuracy and reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the analysis process by using distinct isolation and fragmentation steps for analyte and internal standard ions within the same injection event. By isolating ions based on their mass-to-charge ratios and fragmenting them separately, the method maintains quantitative accuracy while preventing ionization fluctuations from affecting the comparison between analyte and internal standard.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple precursor ions with different m/z ratios are analyzed in a single ion injection event, then ionization process fluctuations are minimized, but ion isolation and fragmentation becomes more complex

Engineering Contradiction:
Improvequantitative mass analysis accuracyVSAvoidion isolation and fragmentation process
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by isolating different precursor ion species based on their mass-to-charge ratios into separate groups before fragmentation. This allows the complex mixture of ions to be processed in organized segments, reducing the complexity of the overall process while maintaining the benefit of simultaneous analysis from a single injection event.

Inventive Principle:
Principle #1Segmentation

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 the accuracy and precision of quantitative mass analysis by reducing fluctuations and improving measurement reliability, enabling efficient analysis of multiple precursor ions with different charge states in a single injection event.

Implementation Method 1

performing a first scan (alternately referred to as a first scan window) at a first value of a resonance ejection q (the value of the Mathieu parameter q at which resonance ejection occurs) to mass-selectively eject to a detector first product ions

Methodology Applied
Scientific EffectResonance ejection: Resonance

Implementation Method 2

a first value of a resonance ejection q (the value of the Mathieu parameter q at which resonance ejection occurs)

Methodology Applied
Scientific EffectMathieu parameter:

Implementation Method 3

fragmenting (dissociating) the first precursor ions, but not the second precursor ions, to generate first product ions

Methodology Applied
Scientific EffectCollision-induced dissociation:

Data Source

PatentEP3379559B1Methods and systems for quantitative mass analysis
Publication Date: 2022.01.05 THERMO FINNIGAN LLC
  • EP3379559B1 patent drawingFigure 1
  • EP3379559B1 patent drawingFigure 2
  • EP3379559B1 patent drawingFigure 3

AI summary

A method of quantitative mass analysis of precursor ion species of different mass-to-charge (m/z) ratios from the same or common ion injection event is disclosed. A plurality of precursor ion species with different respective m/z ratios are introduced into an ion trap mass analyzer at the same time. The precursor ion species are isolated. A first subset of the isolated precursor ions, which are multiply charged and have a first m/z ratio range, is fragmented and scanned by dividing the scan into at least two separate scan windows. A first mass spectrum is generated for the fragment ions of the first subset of precursor ions. A second subset of the isolated precursor ions having a second m/z ratio is fragmented and scanned, and a second mass spectrum is generated for the fragment ions of the second subset of precursor ions.