Toward Comprehensive Sediment Nontarget Screening: A Multilayer Solid-Phase Extraction Workflow for Broader Chemical...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Mass Spectrometry

Background:

• Conventional sample preparation methods for nontarget screening (NTS) in environmental analysis often exhibit physicochemical selectivity.
• This selectivity limits the detectable chemical space, particularly in complex matrices like sediments, prior to high-resolution mass spectrometry (HRMS).
• Single-layer solid-phase extraction (SPE) cartridges show distinct, property-dependent applicability windows, highlighting the need for improved extraction strategies.

Purpose of the Study:

• To develop and validate a multilayer solid-phase extraction (MLSPE) workflow for broad-spectrum extraction of emerging contaminants (ECs) in sediments.
• To reduce extraction-induced selectivity inherent in conventional methods.
• To enable a more comprehensive mapping of the sedimentary exposome for ecological risk assessment.

Main Methods:

• Systematic evaluation of single-layer SPE cartridges (HLB, PWAX/PWCX, C18, PS).
• Development of an optimized MLSPE workflow integrating complementary retention mechanisms.
• Coupling MLSPE with complementary ionization (ESI/APCI) and hybrid acquisition (DDA/DIA) techniques for HRMS analysis.
• Validation using standard reference material (NIST SRM 1936) and application to field sediments.

Main Results:

• The optimized MLSPE workflow achieved balanced extraction across an expansive physicochemical range (log Kow: -2.67 to 17.17; pKa: -1.81 to 12.27).
• Significantly increased recovery (>65%) for structurally diverse validation standards within the 60%-120% range.
• High sensitivity (method detection limits <1 ng/g d.w. for 80% of compounds) and robust precision (RSDs < 20% for 83% of analytes).
• Accurate quantification confirmed by PFOS concentration agreement with certified values.
• Over 500 confident annotations obtained from SRM 1936 and field sediments.
• Revealed elevated concentrations of frequently overlooked QACs and plasticizers in urban-impacted sediments.

Conclusions:

• The developed MLSPE workflow effectively reduces preanalytical selection bias in sediment analysis.
• This coverage-oriented approach provides a comprehensive data foundation for holistic, mixture-based ecological risk assessments.
• The method enables a more authentic mapping of the sedimentary exposome, including previously under-detected contaminants.