Mass Spectrometer MRM Transition Optimization
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Solution Overview
Problem
Simultaneous multicomponent analysis using GC-MS or LC-MS often faces challenges in achieving high-sensitivity measurements for trace compounds while avoiding signal saturation for high-concentration compounds, especially when target compounds vary significantly in concentration and signal intensity, leading to inefficient sample usage and increased measurement time and cost.
Innovation Solution
The method involves selecting specific mass-to-charge ratios and collision energies for each target compound to optimize signal detection, using lower signal intensity transitions and reduced collision energies for high-concentration compounds and higher signal intensity transitions and energies for low-concentration compounds, along with adjusting mass-resolving power and detector gain to prevent signal saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement conditions are optimized for high detection sensitivity (maximum signal intensity) for each compound, then trace compounds can be detected with high sensitivity, but high-concentration compounds will experience signal saturation in the detector
Solution Approach 1:
The patent applies local quality by assigning different MRM transitions and collision energy levels to different compounds based on their individual signal intensity characteristics. For compounds with high signal intensity, alternative MRM transitions with lower intensity are selected, while for compounds with low signal intensity, the most sensitive transitions are used. This compound-specific optimization resolves the contradiction between achieving high detection sensitivity for trace compounds and preventing signal saturation for high-concentration compounds.
2Reliability
If measurement conditions are optimized for high-concentration compounds to avoid signal saturation, then signal saturation is prevented, but detection sensitivity for trace compounds decreases
Solution Approach 1:
The patent employs parameter changes by systematically varying MRM transition selections and collision energy levels across different compounds. The system selects from multiple available MRM transitions for each compound, choosing transitions with appropriate signal intensity characteristics. Collision energy parameters are also adjusted to optimize the balance between detection sensitivity and signal saturation prevention, enabling simultaneous accurate measurement of both trace and high-concentration compounds.
3Measurement precision
If automatic search for optimum MRM transition and collision energy is performed for each compound, then measurement conditions can be optimized for each compound, but the complexity of the analysis process increases
Solution Approach 1:
The patent applies preliminary action by pre-determining and storing multiple candidate MRM transitions and their corresponding signal intensity characteristics for each target compound before the actual analysis. The system maintains a database of compound-specific parameters including multiple MRM transitions, retention times, and signal intensity rankings. During analysis, the system simply retrieves and applies the appropriate pre-optimized parameters based on the compound being measured, avoiding the need for real-time optimization while maintaining high measurement precision.
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 approach enables high-sensitivity detection of trace compounds while preventing signal saturation for high-concentration compounds, reducing sample consumption and measurement time, and lowering operational costs by optimizing measurement conditions for each compound.
Implementation Method 1
a mass-to-charge ratio to be monitored in the SIM measurement or an MRM transition to be monitored in the MRM measurement
Implementation Method 2
in which the precursor ion is fragmented by collision induced dissociation within a collision cell
Data Source
AI summary
In a simultaneous multicomponent analysis for a number of target compounds, an MRM transition which does not give the highest signal intensity but gives a lower signal intensity is selected for a compound having a high measurement sensitivity or a compound having a high measurement target concentration. If the signal intensity is still high, the level of collision energy (CE) is changed from an optimum level. The MRM transition, CE level and other measurement conditions determined for each compound in this manner are stored in a compound-related information storage 41. In the process of preparing a control sequence for the simultaneous multicomponent analysis, the measurement conditions stored in the storage section 41 are used. The use of those conditions prevents the saturation of the signal for a high-concentration compound while ensuring a sufficiently high level of sensitivity for a low-concentration compound.