Examining chemical space coverage of solid phase extraction methods in environmental water for use with LC-MS...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Mass Spectrometry

Background:

• Non-targeted analysis (NTA) in environmental monitoring requires robust sample preparation to capture a wide range of chemical compounds.
• Interpreting complex chemical mixtures from NTA is challenging due to the vast chemical space captured.
• Solid phase extraction (SPE) is a crucial technique for concentrating and purifying analytes prior to instrumental analysis.

Purpose of the Study:

• To explore and optimize multiple solid phase extraction (SPE) methods for enhanced chemical space characterization in non-targeted analysis (NTA).
• To evaluate the extraction efficiency of various SPE chemistries for a diverse range of surrogate chemicals.
• To develop and describe optimized SPE methods suitable for future NTA of environmental water samples.

Main Methods:

• Investigated multiple SPE cartridge chemistries (HLB, WAX, MCX, GCB, WCX) and combinations.
• Evaluated extraction efficiencies using 231 surrogate standards in spiked laboratory and environmental surface water.
• Employed liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) for chemical feature detection and analysis.

Main Results:

• Four optimized SPE methods (HLB, HLB-WAX, HLB-MCX, HLB-WAX-MCX) demonstrated effective retention of diverse chemical classes.
• The HLB-WAX-MCX method retained the highest number of surrogate chemicals (222 out of 231).
• Analysis revealed significant chemical features captured, with benefits observed for MCX-containing methods in retaining polar cations.

Conclusions:

• Optimized SPE methods provide improved chemical space coverage and aid in the interpretation of NTA results.
• The developed methods offer varying chemical retention capabilities, catering to different NTA objectives.
• These optimized SPE protocols serve as valuable tools for future environmental water NTA efforts.