Atmospheric Pressure Ionisation Source for Capillary Priming
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Solution Overview
Problem
Capillaries used in atmospheric solids analysis probes are susceptible to contamination, leading to inaccurate sample analysis due to contaminants deposited on the corona discharge device during high concentration sample analysis, affecting the performance of the ionisation source.
Innovation Solution
An atmospheric pressure ionisation source with a control system that operates in both analytical and capillary priming modes, utilizing different temperature and current ranges for the desolvation heater and corona discharge device to clean the capillary tip and mitigate contaminant deposition on the corona discharge device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the desolvation heater outputs a hot stream of gas onto the capillary during capillary priming, then contaminants on the capillary surface are volatilised and removed, but contaminants may be deposited on the corona discharge device affecting its performance
Solution Approach 1:
The system performs a capillary priming operation before actual sample analysis to pre-clean the capillary surface. The desolvation heater heats the capillary to volatilise and remove contaminants before they can interfere with subsequent analyses, preventing contaminant deposition on the corona discharge device.
Solution Approach 2:
The control system dynamically adjusts the temperature of the desolvation heater between different operating modes: a first temperature for capillary priming/cleaning and a second temperature for normal sample analysis. This dynamic temperature adjustment optimizes cleaning effectiveness while preventing excessive contaminant deposition during analysis.
2Manufacturing precision
If the heating element is heated to a high temperature to clean the capillary, then contaminants are effectively removed, but chemicals may be deposited on the corona discharge device
Solution Approach 1:
The system performs capillary priming at elevated temperatures before actual sample introduction. This preliminary high-temperature treatment removes contaminants from the capillary surface, and the control system ensures this occurs before sample analysis to prevent subsequent deposition issues.
Solution Approach 2:
The control system implements periodic capillary priming operations at scheduled intervals or before specific analyses. This periodic high-temperature cleaning maintains capillary cleanliness while allowing normal lower-temperature operation during routine sample analysis, reducing overall chemical deposition.
3Reliability
If a control system selectively operates in analytical and capillary priming modes with different temperature ranges, then capillary cleaning is improved, but device complexity increases
Solution Approach 1:
The control system is designed to perform multiple functions: it controls both the capillary priming operation and the normal sample analysis operation using a single integrated controller. The system selectively operates in different modes (priming mode with higher temperature, analytical mode with lower temperature) based on operational requirements, managing complexity through multi-functionality.
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
Effectively cleans the capillary tip and reduces contaminant deposition on the corona discharge device, ensuring accurate and reliable sample analysis by volatilising and ionising samples without interference.
Implementation Method 1
the distal end of a capillary (on which sample is to be received) may be heated to a sufficient temperature so as to volatilise and substantially remove the majority of any contaminant(s) of appropriate volatility
Implementation Method 2
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 inlet for receiving at least the distal end of a capillary into the ionisation chamber in use; a desolvation heater including a heating element, for directing a stream of heated gas onto the distal end of the capillary in use; a corona discharge device arranged in the ionisation chamber; and a control system configured to operate the source in a selected one of: an analytical mode, in which the heating element is heated to a first temperature within a first temperature range, and in which a first current within a first current range is supplied to the corona discharge device; and a capillary priming mode, in which the heating element is heated to a second temperature within a second temperature range, and in which a second current within a second current range is supplied to the corona discharge device, wherein the lower limit of the second temperature range is higher than the lower limit of the first temperature range, and the second current range is higher than the first current range.