# Evaluation and Comparison of Three Common Methods for PFAS Extraction from Soybean Tissues

## TL;DR

This study compares three methods for extracting PFAS from soybean tissues and finds that the EPA method 1633 is most effective at low PFAS levels.

## Contribution

The study provides a comparative evaluation of PFAS extraction methods in soybean tissues, identifying EPA method 1633 as the most reliable for low-level PFAS detection.

## Key findings

- EPA method 1633 showed highest and most reproducible recoveries at low PFAS levels in soybean tissues.
- At higher PFAS concentrations, EPA method 1633 remained consistently reliable and never significantly outperformed by other methods.
- A cost comparison supports the preference for EPA method 1633 and MTBE-NaOH for plant-tissue analyses.

## Abstract

This study evaluated three methods, methyl tert-butyl ether-sodium hydroxide (MTBE-NaOH) method, EPA method 1633,
and U.S. Food and Drug Administration (FDA) chemical analytical manual
(CAM) method C-010.03, for their effectiveness in extracting PFAS
from soybean tissues. EPA method 1633 consistently delivered the highest
and most reproducible EIS recoveries when plant tissues contained
PFAS at low levels. Regarding target PFAS extraction efficiency, EPA
method 1633 also demonstrated superior performance at environmentally
relevant low concentrations. At higher PFAS concentrations in plant
tissues, no single method clearly dominated; however, EPA method 1633
remained consistently reliable and was never significantly outperformed
by the other two methods. Overall, EPA method 1633 is recommended
as the default method for routine analyses at typical environmental
PFAS levels, with MTBE-NaOH method preferred when accurate isotopic
correction based on EIS recovery is critical in highly contaminated
plant samples. A cost comparison of these three methods further supports
the preference for EPA Method 1633 and MTBE-NaOH method for plant-tissue
analyses. These findings contribute to PFAS risk assessment in agricultural
and food safety contexts by enhancing the understanding of PFAS interactions
with edible crops.