Multimode Ion Source Combining ESI and APCI for Universal Analysis
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Solution Overview
Problem
Current mass spectrometry techniques lack a universal ionization source capable of efficiently ionizing a broad range of samples with minimal instrumental adjustments, limiting rapid analysis of diverse samples.
Innovation Solution
A multimode ionization source combining electrospray ionization and atmospheric pressure chemical ionization sources, with an assist gas inlet adjacent to a corona needle, enhances ionization efficiency by facilitating ionization of charged aerosols through a corona discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single ionization technique is used, then the instrument is simple to operate, but it cannot efficiently ionize a broad range of diverse samples
Solution Approach 1:
The patent combines electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) sources into a single multimode ion source. The ESI source provides charged aerosol for polar and large molecules, while the APCI source with corona needle provides gas-phase ionization for nonpolar and thermally stable molecules. This merging allows the instrument to analyze diverse samples including polar, nonpolar, large, and small molecules without requiring separate ionization systems.
Solution Approach 2:
The multimode ion source is designed to perform multiple ionization functions within a single device. It can switch between ESI and APCI modes depending on the sample type, providing universal ionization capability for various compound classes including polar, nonpolar, large biomolecules, and small molecules, eliminating the need for multiple specialized ionization systems.
2Productivity
If assist gas is added to facilitate ionization, then ionization efficiency improves, but device complexity increases
Solution Approach 1:
An assist gas inlet is introduced as an intermediary component to deliver assist gas to the corona needle discharge region. The assist gas facilitates ionization by enhancing the corona discharge process and improving ion formation efficiency. This simple addition of a gas delivery system achieves significant improvement in ionization efficiency without substantially increasing overall device complexity.
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 improves ionization coverage, allowing for the analysis of a wider variety of samples with increased efficiency and sensitivity, approaching the goal of a universal ionization source.
Implementation Method 1
The LC eluent is sprayed (nebulized) into a chamber at atmospheric pressure in the presence of a strong electrostatic field and heated drying gas. The electrostatic field charges the LC eluent and the analyte molecules.
Implementation Method 2
The heated drying gas causes the solvent in the droplets to evaporate. As the droplets shrink, the charge concentration in the droplets increases.
Implementation Method 3
an atmospheric pressure chemical ionization (APCI) source including a corona needle having an end positioned downstream from the electrospray ionization source for producing a discharge that further ionizes the charged aerosol
Implementation Method 4
The solvent ions then transfer the charge to the analyte molecules through chemical reactions (chemical ionization).
Data Source
AI summary
A multimode ionization source with improved ionization characteristics that comprises an electrospray ionization source for providing a charged aerosol, an atmospheric pressure chemical ionization (APCI) source including a corona needle having an end positioned downstream from the electrospray ionization source for producing a discharge that further ionizes the charged aerosol, an assist gas inlet positioned adjacent to the corona needle for providing assist gas, the assist gas facilitating ionization of the charged aerosol by the corona discharge, and a conduit having an orifice for receiving ions from the charged aerosol.