Ion Sorting by m/z Using Quadrupole RF Electric Field Arrays
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Solution Overview
Problem
Mass spectrometers face a low duty cycle due to the loss of ions with mass-to-charge ratios outside the isolation window, and existing ion sorting methods, such as those relying on ion mobility, do not achieve a 100% duty cycle and are dependent on specific ion properties.
Innovation Solution
A system and method for sorting ions by mass-to-charge ratio using two arrays of evenly spaced, parallel electrodes with a radio frequency and direct current voltage gradient, creating an array of quadrupole electric fields to trap ions based on their m/z values, allowing for 100% duty cycle and sorting into multiple m/z ranges without relying on ion mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If quadrupole filters are used for ion isolation, then targeted ions can be selected, but ions with m/z values outside the isolation window are lost resulting in low duty cycle
Solution Approach 1:
The device segments the ion beam into multiple spatial channels based on m/z values using a quadrupole field with gradient. Different m/z ranges are directed to different spatial locations, allowing simultaneous analysis of multiple ion populations without loss, thereby resolving the contradiction between precise ion selection and maintaining high duty cycle.
2Productivity
If ion traps are used for mass selective extraction, then duty cycle can be improved, but extraction time for each precursor ion is not negligible causing considerable duty cycle decrease for ion trap mass analyzer
Solution Approach 1:
The device enables continuous ion analysis by eliminating the sequential extraction process. All precursor ions across different m/z ranges are trapped and analyzed simultaneously in parallel spatial channels, removing the time loss associated with sequential extraction and achieving near 100% duty cycle.
3Productivity
If multiple mass analyzers are used to improve duty cycle, then more precursor ions can be analyzed, but ions must be multiplexed or sorted into multiple mass analyzers increasing device complexity
Solution Approach 1:
The device merges the functions of multiple mass analyzers into a single instrument by using a quadrupole field with gradient to create multiple spatial analysis channels. This allows one mass analyzer to simultaneously analyze multiple precursor ions across different m/z ranges that would traditionally require multiple separate analyzers, reducing device complexity while maintaining high duty cycle.
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
The system effectively increases the duty cycle of mass spectrometers to nearly 100% by sorting ions based on m/z values, enabling efficient multiplexing and trapping of ions across multiple m/z ranges, improving the efficiency of mass analysis.
Implementation Method 1
an array of N-1 different quadrupole RF electric fields. When ions of an ion beam of a mass spectrometer are introduced in the uniform gap near a quadrupole RF electric field with a lower RF voltage amplitude, the DC electric field causes the ions to drift toward quadrupole RF electric fields with increasing RF voltage amplitudes where the ions are trapped according to their m/z values
Implementation Method 2
The applied DC field gradients and beneficial pressures enable ion mobility physics to apply to the ion transport (e.g., in a time frame of less than about 200 μsec) and separation of the ions, resulting in the movement of ions from the first axial channel to one or more adjacent axial channels
Data Source
AI summary
An RF voltage is applied across each electrode of a first array of evenly spaced, parallel, and coplanar electrodes and its corresponding electrode of a second array of evenly spaced, parallel, and coplanar electrodes. The RF voltage varies in amplitude according to an RF voltage amplitude gradient. The RF voltage produces an array of different quadrupole RF electric fields in a uniform gap between the first array and the second array. A DC voltage is superimposed on each electrode of the first array and its corresponding electrode of the second array. The DC voltage varies according to a DC voltage gradient in order to produce a DC electric field in the uniform gap. When ions are introduced in the uniform gap, the DC electric field causes the ions to drift toward quadrupole RF electric fields with increasing RF voltage amplitudes where the ions are trapped according to their m/z.