Optimized hidden target screening for very polar molecules in surface waters including a compound database inquiry

Area of Science:

• Environmental Chemistry
• Analytical Chemistry

Background:

• Highly polar trace organic compounds, persistent, mobile, and toxic (PMT) or very persistent and very mobile (vPvM), pose risks to water supplies.
• Existing analytical methods, like liquid chromatography-mass spectrometry, have limitations in detecting these very polar chemicals.

Purpose of the Study:

• To develop an analytical method for detecting a broad polarity range of organic compounds in water.
• To establish a workflow for identifying very polar molecules using nontarget screening (NTS) and a compound database.

Main Methods:

• Coupling reversed-phase liquid chromatography (RPLC) with hydrophilic interaction liquid chromatography (HILIC) and high-resolution mass spectrometry (HRMS).
• Optimizing data processing for NTS data, including feature extraction and filtering.
• Utilizing the STOFF-IDENT database and FOR-IDENT NTS platform for compound identification based on accurate mass and physicochemical properties.

Main Results:

• The polarity-extended chromatography successfully separated and detected very polar compounds from surface water samples.
• A workflow was developed to process NTS data, leading to the identification of 64 candidate compounds from 33 river water samples.
• Three PMT candidates (guanylurea, melamine, 1,3-dimethylimidazolidin-2-one) were validated using reference standards.

Conclusions:

• Polarity-extended chromatography is effective for the reproducible separation and detection of very polar compounds in surface waters.
• A transparent and robust data processing workflow for NTS is available for identifying emerging very polar contaminants in the aquatic environment.