ICR Mass Spectrometer Filling Level Control via Reference Analyzer

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Solution Overview

Problem

Ion cyclotron resonance mass spectrometers face frequency shifts due to space charge variations and peak coalescence, leading to incorrect mass measurements, especially when dealing with high ion densities and mixtures of ions with similar masses.

Innovation Solution

Operating an ICR mass analyzer in parallel with a reference mass analyzer, using the reference mass spectra to control the filling process of the ICR mass analyzer by regulating the ion mixture based on parameters such as the maximum of a sliding average of the ion current, which accounts for the distribution of ion masses and reduces interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the ion supply parameters are adjusted to maintain constant total ion charge, then the overall signal level is stabilized, but frequency shifts still occur due to variations in ion composition and mass distribution

Engineering Contradiction:

Improvetotal ion charge stabilityVSAvoidfrequency measurement reproducibility

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent extends control from single parameter (total charge) to multiple parameters including ion density, mass distribution, and composition. By monitoring and controlling these additional parameters through reference mass spectrometry or advanced detection, the system maintains not only constant total charge but also stable mass distribution, preventing frequency shifts caused by compositional variations

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If a reference mass spectrometer is added to monitor ion composition for improved filling control, then mass distribution control is improved, but device complexity increases

Engineering Contradiction:

Improveion composition controlVSAvoiddual mass spectrometer system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the reference mass spectrometer serve dual functions: (1) monitoring ion composition and mass distribution for feedback control, and (2) providing reference mass spectra for analytical purposes. This multi-functionality justifies the additional instrument by extracting maximum utility from it, reducing the effective complexity burden

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the reference mass spectrometry function with the analytical measurement function in an integrated system. Both functions share common infrastructure (vacuum system, ion source, data processing), and the reference measurements are used to optimize the analytical measurements, creating a synergistic system where the whole is greater than the sum of parts

Inventive Principle:

Principle #5Merging (Combining)

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 stabilizes the filling level, minimizing frequency shifts and peak coalescence, thereby improving mass resolution and accuracy by ensuring optimal ion distribution within the measuring cell.

Implementation Method 1

a reference mass analyzer (202) are operated in parallel, wherein a fraction each of the same mixtures of ions (104) obtained from the same flow of substance mixtures by the same ionization methods are supplied to both mass analyzers

Methodology Applied

Scientific EffectMass spectrometry:

Implementation Method 2

Electrospray ionization is nowadays the most widely used ionization method for the ICR mass spectrometry of biomolecules

Methodology Applied

Scientific EffectElectrospray ionization:

Implementation Method 3

Ionization by laser desorption (LDI) has for a long time been used successfully to transfer large organic molecules from a solid surface into the gaseous phase, and thereby to ionize them

Methodology Applied

Scientific EffectLaser desorption: Laser Ablation

Implementation Method 4

the ions are excited into cyclotron movement under ultrahigh vacuum conditions in a very intense magnetic field and the frequency of these circulating movements of the ions is measured

Methodology Applied

Scientific EffectIon cyclotron resonance: Cyclotron Radiation

Implementation Method 5

a very intense magnetic field of seven, nine, twelve or even fifteen Tesla, generated by superconducting coils held at the temperature of liquid helium

Methodology Applied

Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentUS7495209B2Control of the filling level in ion cyclotron resonance mass spectrometers

Publication Date: 2009.02.24 BRUKER DALTONIK GMBH & CO KG

AI summary

The invention relates to methods and devices for regulating the filling level in measuring cells of ion cyclotron resonance mass spectrometers so that it is optimal for mass resolution and mass accuracy. The invention consists in supplying a fraction of the samples to a second reference mass spectrometer operated in parallel, and employing the mass spectra obtained from this reference mass spectrometer to regulate the filling level in the ion cyclotron resonance mass spectrometer.