Dual Ionization Source Voltage Adjustment for Mass Spectrometry
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Solution Overview
Problem
The dual ionization source in mass spectrometers, which combines ESI and APCI sources, faces challenges in achieving sufficient ionization efficiency for components with varying polarities, leading to suboptimal detection intensity for quantitative analysis.
Innovation Solution
A mass spectrometer and method that involve an ionization source with adjustable ESI and APCI voltages, allowing multiple ionization conditions to be set and tested, with a selector to choose results with optimal detection intensity for each component, ensuring high sensitivity and accuracy in mass spectrometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If average ESI and APCI voltages are applied in a dual ionization source, then both high-polarity and low-polarity components can be ionized, but the ionization efficiency for some components becomes too low to produce sufficient detection intensity
Solution Approach 1:
The patent implements dynamic switching between ESI and APCI ionization modes based on the polarity characteristics of the analyte. The system automatically selects the appropriate ionization mode and adjusts voltage parameters in real-time according to the sample type, transforming the static average-voltage approach into a dynamic adaptive system that optimizes ionization efficiency for each specific component
Solution Approach 2:
The patent changes the ionization parameters (voltage values, gas flow rates, temperature) according to the specific polarity characteristics of the analyte. By adjusting these parameters dynamically rather than using fixed average values, the system achieves optimal ionization efficiency for both high-polarity and low-polarity components, resolving the contradiction between versatility and measurement precision
2Measurement precision
If multiple ionization conditions are tested for each component, then optimal detection intensity can be achieved, but the analysis time increases
Solution Approach 1:
The patent performs preliminary classification of analytes based on their polarity characteristics before full analysis. By pre-establishing which ionization mode (ESI or APCI) is suitable for each type of component, the system avoids time-consuming trial-and-error testing of multiple conditions during actual analysis, thus reducing analysis time while maintaining optimal detection sensitivity
Solution Approach 2:
The system incorporates feedback mechanisms that use preliminary test results to automatically determine the optimal ionization conditions for subsequent analysis. Based on initial detection data, the system adjusts ionization parameters and selects the most effective mode, eliminating the need to manually test all possible conditions and significantly reducing overall analysis time
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 the production of ions with sufficient intensity for each component, regardless of polarity, resulting in highly sensitive and accurate mass spectrometry results.
Implementation Method 1
an electrospray ionization (ESI) source... The liquid sample and mobile phase which have been separated into components in the liquid chromatograph and introduced into the ESI probe are discharged from this probe in the form of droplets which are electrically charged due to the ESI voltage applied to the ESI probe
Implementation Method 2
a needle (corona needle), located near the exit port of the ESI probe, for inducing a corona discharge by supplying high voltage... low-polarity components contained in the sample are not ionized at this stage; they are ionized by exchanging electric charges with the mobile phase which is ionized by the corona discharge at the corona needle
Data Source
AI summary
A mass spectrometer including an ionization source including an ESI probe (201), an ESI power source (24), a corona needle (202) and an APCI power source (24); an ionization condition storage section (41) for storing a plurality of ionization conditions related to the liquid sample, set by an analysis operator, with the ionization conditions differing from each other in the value of the ESI voltage or/and the value of the APCI voltage; a mass spectrometry executer (43) for conducting a mass spectrometry for an ion generated from the liquid sample using each of the plurality of ionization conditions; and a mass spectrometry result selector (44) for selecting, for each of the one or plurality of components, a mass spectrometry result in which the ion is detected with a suitable level of intensity for an analysis, from the mass spectrometry results respectively obtained for the plurality of ionization conditions.