Establishing the Updated US EPA 537.1 for PFAS Reliably in a Lab by Automated Sample Preparation with the Combination of XANA and D-EVA

Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Prepared by A. Koepf, T. Kerkemeier, S. Wierer, F. Wuppermann
LCTech GmbH, Daimlerstr. 4, Obertaufkirchen, Bavaria, 84419, Germany


Contact Information: [email protected]; 016090667020


ABSTRACT

The US EPA tightened in the revised Method 537.1, the requirements for PFAS analysis in drinking water with lower limits and new analytes. After enriching and extracting on an offline solid phase extraction (SPE) the sample is concentrated to dryness and resolved for LC-MS/MS analysis. For the validation of this method a list of acceptance and quality control criteria have to be fulfilled, which in a manual procedure requires a very reliable and precise work, as well as an adapted choice of materials applied. One challenge of the application is to keep the background levels of the analytes as low as possible. The successful validation of automated SPE purification on a FREESTYLE XANA PFAS instrument according to US EPA 537.1, has been shown in a previous presentation. Now the focus lays on the advantages of an automated and dedicated unit for the subsequent concentration to dryness as afterburning lead to possible loss of neutral PFAS and handling advantages save time and errors.
Easy handling starts by the vacuum centrifugation directly in the EPA-compliant elution tube from the FREESTYLE-XANA, which avoids already a first transfer step. High recoveries with great precision during the evaporation step to dryness are easily achievable due to the use of IR light, gentle pressure reduction and the technique to Stop at dryness by a specially developed sensor. Even samples with high residual water content, as is common with this method, can be concentrated to dryness unattended and due to the centrifugal force, the final volume remains in the tip of the vessel and can be transferred directly into the GC vial without rinsing steps. Due to the cold trap, no solvent vapours are emitted into the laboratory, no fume cupboard necessary. Tests have shown that neither blank values nor cross-contamination occurs in the D-EVA and the values reached show high selectivity and correctness.