Mass Spectrometry Ion Peak Correction for Accurate Ion Counting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mass spectrometers do not systematically correct for the mass and charge dependence of ion areas, leading to inaccuracies in estimating the number of ions, particularly in time-of-flight mass analyzers, where ions with varying masses and charges are detected.
Innovation Solution
A correction function is developed to describe the relationship between average single ion areas and ion mass, mass-to-charge ratio, and charge, allowing for systematic correction of ion area dependencies across the operational range of mass analyzers, enabling precise estimation of ion numbers and improved quantification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ion peak area is used to estimate ion number without correction, then the method is simple and fast, but the measurement precision deteriorates due to mass and charge dependence
Solution Approach 1:
A correction function is pre-calculated and stored in a lookup table format, allowing the system to apply corrections by simple table lookup rather than complex real-time calculations. The correction function accounts for mass and charge dependence of ion detection efficiency, enabling accurate ion number estimation while maintaining fast processing speeds.
Solution Approach 2:
The patent transforms the complex mass and charge dependence relationship into a simplified correction function that varies parameters systematically. By expressing the correction factor as a function of mass-to-charge ratio and applying predetermined correction values, the system achieves high measurement precision without requiring complex real-time computations.
2Measurement precision
If mass and charge dependent correction is applied to all ion peaks, then the measurement precision improves, but the loss of time increases due to additional calculation steps
Solution Approach 1:
The correction function is pre-calculated and stored in a lookup table during system initialization or calibration phase. During actual data processing, the system retrieves correction factors from this pre-computed table based on ion mass-to-charge ratios, avoiding time-consuming real-time calculations while maintaining high quantification accuracy.
Solution Approach 2:
The patent creates a simplified representation of the complex mass and charge dependence relationship in the form of a correction lookup table. This copy of the correction data allows rapid retrieval and application during analysis without requiring access to the full complexity of the underlying physical relationships.
3Reliability
If automatic gain control is implemented without mass and charge correction, then the operation is simpler, but the reliability deteriorates due to inaccurate ion number estimation
Solution Approach 1:
The automatic gain control system uses a pre-calculated correction function that accounts for mass and charge dependence. During gain control operations, the system retrieves appropriate correction factors from this pre-prepared data structure, enabling reliable ion number estimation across different mass ranges without requiring complex real-time adjustments.
Solution Approach 2:
The patent implements a correction mechanism that systematically adjusts for mass and charge parameters in the automatic gain control algorithm. By incorporating predetermined correction factors that vary with ion mass-to-charge ratio, the system achieves reliable quantification across different mass ranges while maintaining relatively simple control logic.
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 solution provides accurate and straightforward correction of ion area dependencies, enhancing the accuracy of ion number estimation and quantification in mass spectrometry, particularly for time-of-flight mass analyzers, and improves automatic gain control methods by accounting for mass and charge variations.
Implementation Method 1
Time-of-flight (ToF) mass analysers utilise the property that the travelling time of an ion in an electrostatic field is proportional to the square root of the ion's mass-to-charge ratio (m/z)
Implementation Method 2
Time-of-flight (ToF) mass analysers utilise the property that the travelling time of an ion in an electrostatic field is proportional to the square root of the ion's mass-to-charge ratio (m/z)
Implementation Method 3
Ions are ejected from an ion source, accelerated to a desired energy, and impinge upon an ion detector after traveling a specified distance. The signal generated by the detector is recorded
Data Source
AI summary
A method of analysing a signal generated by a mass analyser comprises receiving a signal generated by the mass analyser, determining the area of a first ion peak of one or more ion peaks in the signal, and estimating the number of ions that contributed to the first ion peak. The number of ions that contributed to the first ion peak is estimated by determining a correction to be applied to the area of the first ion peak from a correction function, and applying the correction to the area of the first ion peak. The correction function describes a relationship between average single ion area and ion mass, mass-to-charge ratio and/or charge for the mass analyser.