An Automated Sample Extraction and Cleanup Workflow Prior to LC-MS/MS for Analysis of PFAS in Solids and Fish Tissues

Per- and Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Prepared by K. Organtini1, B. Liu2, A. Stell2, I. Wan3
1 - Waters Corporation, 34 Maple St, Milford, MA, 01757, United States
2 - CEM Corporation, 3100 Smith Farm Rd, Matthews, NC, 28104, United States
3 - Promochrom Technologies, 13351 Commerce Parkway, Unit 1103, Richmond, BC, V6V 2X7, Canada


Contact Information: [email protected]; 508-482-3242

ABSTRACT

US EPA Method 1633 has become the foundational method for analysis of PFAS in non-potable water matrices, soils, biosolids and tissues in the United States. The method is quite complex for solid and tissue samples requiring a lengthy extraction followed by sample clean up. With this method becoming in demand, laboratory throughput and efficiency must be considered for maximum laboratory success. Automation and instrument sensitivity are investigated as avenues to increasing laboratory efficiency via higher sample throughput.

An automated workflow was utilized to extract, clean up and analyze soil, biosolids and fish tissue samples. An automated solvent extraction system was used for the extraction of samples using the recommended extraction solvents from EPA method 1633. Sample clean-up was then fully automated using an automated SPE system and SPE cartridges containing both WAX and GCB sorbents. Targeted LC-MS/MS analysis of 40 PFAS compounds was performed using a highly sensitive mass spectrometer.

Equivalency of the automated workflow was demonstrated using the quality control criteria of EPA 1633. Additionally, certified reference materials for biosolids, soil and fish tissue were all processed and analyzed using this workflow with all results falling within the acceptance criteria of each reference material.

The automated solvent extraction system was able to reduce sample extraction times to approximately 6 minutes each. Manual extraction steps for soil samples require 95 minutes or more and over 16 hours for tissue samples. This significantly reduces the time spent on extraction of samples. Additionally, the automated SPE system processes a batch of samples (each ~50 mL) in approximately one hour. Finally, LC-MS/MS sample analysis was performed using an 11 minute method. The reduction of time spent prepping samples allows the full extraction to analysis workflow to be possible in a typical 8 hour shift while maintaining precision, accuracy and confidence in final results.