Background Correction in Tandem Mass Spectrometry Quantitation
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Solution Overview
Problem
Tandem mass spectrometry based quantitation using isobaric labels faces challenges due to non-deterministic signal-to-noise ratios and background molecule interference, where an unknown amount of analyte signal is attributed to nearly isobaric background molecules, complicating the determination of relative concentrations.
Innovation Solution
The method involves obtaining additional tandem mass spectrometry information at different elution times to separate reporter ion signal contributions from background noise, using linear equations to calculate corrected reporter ion intensities by assuming invariant background signal across reporter ion channels, and subtracting background noise from measured reporter ion signals to obtain accurate quantitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If isobaric labels are used for MS/MS based quantitation, then multiplexing capability and relative concentration determination are improved, but background molecule interference and signal-to-noise ratio become problematic
Solution Approach 1:
The patent segments the total reporter ion signal into two distinct components: analyte signal and background signal. By performing MS/MS at multiple elution times, the method separates the time-dependent analyte signal from the relatively constant background signal, allowing independent measurement and subsequent subtraction of background contributions from each reporter ion channel.
Solution Approach 2:
The patent introduces an intermediary measurement approach by using additional MS/MS acquisitions at different elution times as a mediator to characterize the background signal. This intermediary data enables the calculation of background contributions without directly measuring them during the primary quantitation acquisition, thereby preserving the integrity of the main analyte signal measurement.
2Measurement precision
If additional tandem mass spectrometry information is collected at different elution times, then background noise separation is improved, but measurement time and data processing complexity increase
Solution Approach 1:
The patent applies partial action by performing MS/MS acquisitions at a limited number of strategically selected elution times rather than continuous monitoring. The method uses just enough additional measurements (typically 2-3 time points) to adequately characterize the background signal and enable correction, avoiding the time cost of exhaustive continuous measurement while achieving sufficient background separation.
Solution Approach 2:
The patent performs preliminary MS/MS acquisitions at additional elution times to pre-characterize the background signal before final quantitation calculation. By obtaining background information in advance through these preliminary measurements, the method enables efficient background subtraction during data analysis without requiring time-consuming iterative measurements during the quantitation process.
Data Source
AI summary
A corrected reporter ion intensity is calculated in tandem mass spectrometry based quantitation using isobaric labels. An analyte in each of two or more samples of a mixture of samples is labeled with a different isobaric label. The analyte is eluted from the mixture of samples and intensities of the eluting analyte are measured. An analyte intensity is selected at each of at least two times from the measured intensities. Tandem mass spectrometry is performed on the eluting analyte at each of the at least two times. A plurality of reporter ion intensities is produced. A system of linear equations is created expressing each reporter ion intensity of the plurality of reporter ion intensities as a sum of a background noise intensity and the product of a fragmentation efficiency and an analyte intensity. A corrected reporter ion intensity is calculated from a solution of the system of linear equations.