Biopolymer Ion Selection via Target Spectrum Transformation
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Solution Overview
Problem
Current methods for selecting the most suitable ion species for fragmentation from complex biopolymer mass spectra are inefficient, often requiring extensive computation time and failing to accurately identify proteins with overlapping isotopic distributions, especially in mixtures with proteins of varying retention times and high molecular masses.
Innovation Solution
A rapid method for selecting the most favorable ion species for fragmentation by transforming the mass spectrum into a target spectrum, multiplying M/z values by integers representing charge numbers, and summing intensities within defined ranges to identify prominent biopolymer signals, allowing for real-time selection and optimal mass filter settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods are used to select ion species for fragmentation, then identification accuracy can be maintained, but computation time becomes excessively long and productivity decreases
Solution Approach 1:
The patent segments the complex mass spectrum into multiple charge state ranges (e.g., z=2-10, z=11-20, etc.). For each charge state range, a separate target spectrum is generated by multiplying M/z values by integers representing charge numbers and summing intensities. This segmentation allows the system to process different charge state regions independently and efficiently, reducing overall computation time while maintaining identification accuracy through comprehensive coverage of all charge states.
Solution Approach 2:
The patent performs preliminary generation of target spectra by multiplying M/z values by charge numbers and summing intensities before the actual ion species selection process. This preliminary action pre-processes the complex mass spectrum data, organizing it into target spectra that highlight prominent biopolymer signals. By doing this preparation work in advance, the system avoids repeated complex calculations during the selection phase, significantly reducing computation time while preserving identification accuracy.
2Measurement precision
If comprehensive analysis of all ion species is performed, then identification accuracy improves, but the complexity of the analysis process increases
Solution Approach 1:
The patent divides the analysis process into distinct segments: generating target spectra for different charge state ranges, identifying prominent signals in each target spectrum, and selecting ion species based on these prominent signals. This segmentation simplifies the overall complex analysis by breaking it into manageable steps, each with clear input and output, making the process easier to implement and control while maintaining comprehensive analysis coverage.
Solution Approach 2:
The patent introduces target spectra as an intermediary representation between the raw complex mass spectrum and the final ion species selection. The target spectrum serves as a mediator that transforms the complex overlapping isotopic distributions into a simplified form where prominent biopolymer signals are highlighted. This intermediary step reduces analysis complexity by providing a clearer pathway from raw data to identification while preserving all necessary information for accurate identification.
3Productivity
If ion species selection is performed rapidly, then productivity increases, but the ability to handle overlapping isotopic distributions deteriorates
Solution Approach 1:
The patent performs preliminary generation of target spectra by multiplying M/z values by charge numbers and summing intensities across different charge states. This preliminary action pre-processes overlapping isotopic distributions into a form where prominent signals are enhanced and more easily distinguishable. By doing this preparation in advance, the system can rapidly identify ion species without sacrificing the ability to resolve overlapping distributions, as the overlap resolution work has already been done in the target spectrum generation phase.
Solution Approach 2:
The patent creates target spectra as simplified copies or representations of the complex mass spectrum, where the essential information about prominent biopolymer signals is preserved but the complexity of overlapping isotopic distributions is reduced. These target spectra serve as easier-to-analyze copies that maintain the critical information needed for accurate identification while enabling faster processing. The system works with these simplified copies rather than the full complex spectrum during the selection phase.
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
Enables rapid and accurate selection of ion species for fragmentation, reducing computation time to milliseconds and improving the identification of biopolymers in complex mixtures, even when proteins have overlapping isotopic distributions, by focusing on the most intense signals and minimizing overlap.
Implementation Method 1
The ionization is usually carried out by electrospraying (ESI). For each protein, the mass spectrum contains regular patterns of multiply charged ions with a broad, usually relatively smooth distribution of the intensities for the ions with different charge numbers z
Implementation Method 2
The isolation of the selected ion species and its fragmentation are usually carried out in quadrupole mass filters
Implementation Method 3
The mass spectrometric analysis is usually carried out in time-of-flight mass spectrometers with orthogonal ion injection (OTOF)
Implementation Method 4
The multiply charged protein molecules are usually fragmented by transferring electrons from suitable, negatively charged donor molecule ions (ETD=electron transfer dissociation)
Data Source
AI summary
The invention relates to the selection of the most favorable ion species for the acquisition of fragment ion mass spectra when the ionization creates biopolymers in different charge states. The invention proposes a particularly fast method of selecting the most favorable parent ions for fragmentation of the different biopolymers from mass spectra, where the ionization is by electrospray ionization (ESI) or other ionization methods which produce similarly diverse charge states and which, for each biopolymer, contain many signal patterns of ions of the different charge states and different isotopic compositions. The selection is carried out in such a way that it does not measure more than one ion species from one biopolymer. Moreover, the most favorable filter pass-band width for isolating an ion species for fragmentation can be stated in each case.