Evaluation of a liquid electron ionization liquid chromatography-mass spectrometry interface

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Chromatography

Background:

• Liquid chromatography-mass spectrometry (LC-MS) is a vital analytical technique.
• Accessing electron ionization (EI) spectra from LC-MS has been challenging.
• Existing LC-MS interfaces often suffer from matrix effects impacting quantification.

Purpose of the Study:

• To evaluate and optimize the Liquid Electron Ionization (LEI) interface for LC-MS.
• To understand the fundamental mechanisms of the LEI interfacing process.
• To improve the robustness and sensitivity of LEI for untargeted analysis.

Main Methods:

• Development and installation of specialized hardware to manage eluent and prevent analyte degradation.
• Optimization of interface parameters including capillary dimensions, temperature, and flow rates.
• Selection and analysis of test compounds (environmental pesticides) based on physicochemical properties.

Main Results:

• Achieved low-picogram detection limits for pesticides in a soil matrix using MRM.
• Obtained high-quality EI mass spectra for pesticide mixtures.
• Demonstrated negligible matrix effects, enabling accurate quantitative analysis.
• Successfully improved interface robustness and sensitivity through hardware and parameter optimization.

Conclusions:

• Liquid Electron Ionization (LEI) effectively bridges liquid chromatography with electron ionization mass spectrometry.
• LEI provides access to extensive EI spectral libraries for untargeted LC-MS analyses.
• The optimized LEI interface offers a robust and sensitive platform for accurate environmental pesticide quantification.