Non-extractable PFAS in functional textiles - characterization by complementary methods: oxidation, hydrolysis, and...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Per- and polyfluoroalkyl substances (PFAS) are crucial for water-repellent textile finishes.
• Existing PFAS extraction methods struggle to detect non-extractable side-chain fluorinated polymers (SFPs).
• SFPs are polymers with fluorinated side-chains, imparting desired material properties.

Purpose of the Study:

• To compare the analytical performance of various techniques for SFP detection in textiles.
• To evaluate methods including oxidation (dTOP, PhotoTOP), hydrolysis (THP), standard extraction, extractable organic fluorine (EOF), and total fluorine (TF).
• To assess the accuracy and efficiency of direct textile analysis versus extract-based methods.

Main Methods:

• Applied dTOP and PhotoTOP oxidation assays directly to textile samples.
• Utilized THP hydrolysis assay on textile samples.
• Compared results with standard extraction, EOF, and TF analyses on textile extracts.

Main Results:

• Direct oxidation (dTOP, PhotoTOP) and hydrolysis (THP) captured significantly higher fractions of total fluorine (TF) compared to extract-based methods (EOF, target analysis).
• Extract-based methods detected 25-50 times lower TF fractions than direct analysis.
• Detected perfluoroalkyl carboxylic acids (PFCAs) and fluorotelomer alcohols (FTOHs) indicated the continued use of long-chain SFPs in textiles.

Conclusions:

• Direct analysis methods (oxidation, hydrolysis) are superior for quantifying SFPs in textiles.
• Traditional extraction methods underestimate the presence of fluorinated polymers in fabrics.
• The study highlights the prevalence of long-chain SFPs, necessitating improved analytical strategies.