Atmospheric Pressure Ionization Source with Perpendicular Capillary and Nozzle Axes
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Solution Overview
Problem
Existing atmospheric pressure ionization sources face challenges in ensuring consistent and efficient volatilization and ionization of samples due to capillary fragility and contamination, leading to incomplete heating and extended analysis times, especially with high boiling point compounds, which results in undesirable background in mass spectra.
Innovation Solution
The design includes a specific arrangement of an ionization chamber with a capillary aperture, a desolvation heater nozzle, a corona discharge device, and a mass spectrometer inlet cone, where the capillary axis is perpendicular to the nozzle axis, and the corona axis is coaxial with the cone axis, optimizing the distances and alignment for effective heating and ionization, ensuring the sample is efficiently vaporized and ionized before entering the mass spectrometer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the capillary is made fragile and susceptible to contamination to ensure reliable and accurate analysis, then the measurement precision is improved, but the reliability of the device deteriorates
Solution Approach 1:
The capillary system is segmented into a replaceable capillary component and a permanent source housing. The capillary can be easily removed and replaced without damaging the expensive source housing, thus maintaining measurement precision while improving overall system reliability through component replacement rather than entire system replacement.
Solution Approach 2:
The capillary is designed as a disposable or easily replaceable component that can become contaminated during use. Instead of requiring the entire source to be replaced, only the inexpensive capillary needs replacement, maintaining analysis accuracy while improving device reliability.
2Device complexity
If the sample is not adequately heated by the nozzle, then the device complexity is reduced, but the productivity deteriorates due to extended analysis times
Solution Approach 1:
The heating system parameters (temperature, gas flow rate, nozzle-to-capillary distance) are optimized to achieve complete volatilization of high boiling point compounds in a short time. By adjusting these parameters, the system achieves high productivity without adding complex heating mechanisms.
Solution Approach 2:
The system applies excessive heating action by directing a focused stream of heated gas directly onto the capillary tip, ensuring complete volatilization of even high boiling point compounds. This partial concentration of heating energy achieves rapid and complete sample vaporization, improving analysis speed without requiring complex heating systems.
3Manufacturing precision
If the sample is not adequately heated by the nozzle, then the manufacturing precision requirements are reduced, but the loss of time increases due to extended analysis times
Solution Approach 1:
The system optimizes operational parameters (heated gas temperature, flow rate, nozzle-to-capillary distance) to compensate for variations in manufacturing precision. This allows the system to achieve complete volatilization and rapid analysis even with moderate alignment precision, reducing both manufacturing requirements and 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 configuration ensures reliable and accurate analysis by ensuring complete volatilization and ionization of samples, reducing analysis time and minimizing background noise in mass spectra, thereby improving the overall performance of the atmospheric pressure ionization source.
Implementation Method 1
the sample is volatilised into the gas phase using a heated gas, such as nitrogen, exiting a desolvation heater
Implementation Method 2
the sample is volatilised into the gas phase
Implementation Method 3
the sample is then ionised using a corona discharge pin
Data Source
AI summary
An atmospheric pressure ionisation source comprising: an ionisation chamber, comprising an aperture for receiving at least the distal end of a capillary into the ionisation chamber in use, the aperture having a capillary axis; a desolvation heater having a nozzle, for directing a stream of heated gas onto the distal end of the capillary in use, the nozzle having a nozzle axis; a corona discharge device including a corona pin having a corona axis, the corona pin for ionizing a sample in the ionisation chamber in use; and an inlet cone of a mass spectrometer arranged in the ionisation chamber, the inlet cone defining a cone entrance having a cone axis, wherein the cone axis is substantially coaxial with the corona axis and the capillary axis is substantially perpendicular to and intersects with the nozzle axis.