Mass Spectrometer Noise Subtraction via Segmented Acquisition
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Solution Overview
Problem
High repetition rates of solid-state lasers and increasing clock speeds in TOF mass spectrometers introduce challenges in generating precise delays, stabilizing power supplies, and reducing noise in mass spectrum data, particularly in MALDI TOF mass spectrometers.
Innovation Solution
A method is implemented to acquire noise mass spectrum data by modifying the ion detector's acquisition cycles to exclude ions from the ion source, allowing for the subtraction of noise from signal data, thereby reducing systematic noise and improving the signal-to-noise ratio. This involves similar cycles to signal acquisition but with no ion detection, using high voltage pulses and operating electronics to represent noise, which is then subtracted from the signal data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high repetition rates of solid-state lasers are used in TOF mass spectrometers, then productivity is improved, but measurement precision deteriorates due to increased noise in mass spectrum data
Solution Approach 1:
The acquisition cycle is segmented into two distinct modes: signal acquisition cycles where ions are detected, and noise acquisition cycles where ions are blocked. This segmentation allows separate measurement and subtraction of noise components, enabling high repetition rates while maintaining measurement precision through mathematical removal of systematic noise.
Solution Approach 2:
The noise component is extracted from the mass spectrum data through dedicated noise acquisition cycles. By using the ion gate to block ions during noise acquisition cycles, the system isolates and captures only the noise signal, which is then subtracted from the total signal to improve the signal-to-noise ratio.
2Measurement precision
If high speed digital and analogue electronics are used to accurately measure ion time of flight, then measurement precision is improved, but object-generated harmful factors worsen due to increased electronic noise
Solution Approach 1:
The electronic noise generated by high-speed digital and analogue electronics is converted from a harmful factor into a measurable and removable component. By acquiring noise data through dedicated noise acquisition cycles and subtracting it from the signal data, the system transforms the previously harmful electronic noise into a correctable artifact, thereby maintaining measurement precision while using high-speed electronics.
3Measurement precision
If high voltage pulses are used to accelerate and gate ions, then measurement precision is improved, but object-generated harmful factors worsen due to radiated electrical noise
Solution Approach 1:
The ion gate serves as an intermediary component that can be independently controlled to block ions during noise acquisition cycles. By using the ion gate as a mediator, the system can acquire noise data without ions reaching the detector, thereby capturing the radiated electrical noise from high voltage pulses separately from the ion signal for subsequent subtraction.
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 method significantly reduces systematic noise in mass spectrum data, enhancing the signal-to-noise ratio and improving the accuracy of mass/charge ratio measurements by isolating and subtracting noise, thus stabilizing the power supplies and reducing electronic noise manifestations.
Implementation Method 1
a laser for ionising sample material by firing light at the sample material
Implementation Method 2
measuring their time of flight to an ion detector... ions of different mass/charge ratios are separated by their different speeds and so are detected by the ion detector at different times
Data Source
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AI summary
The present invention is concerned with methods and apparatuses for generating mass spectrum data using a mass spectrometer by subtracting noise mass spectrum data representative of noise in the mass spectrometer from signal mass spectrum data representative of the mass/charge ratio of ions in a sample material. This produces a modified signal mass spectrum data representative of the mass/charge ratio of ions in the sample material. The method includes acquiring and subtracting noise mass spectrum data representative of noise in the mass spectrometer or alternatively subtracting noise mass spectrum data from a previously acquired or pre- stored noise spectrum data. Embodiments demonstrate reduced noise and in particular reduced systematic noise compared with the originally acquired signal mass spectrum data.