Emerging Analytical and Forensics Tools

ZCATS – Testing for a broad range of PFAS on non-porous surfaces

ZCATS is a state-of-the-art surface wipe test for a broad range of Per and Polyfluoroalkyl Substances (PFAS) on non-porous surfaces. Developed in collaboration with Dr. Ian Ross, ZCATS uses the best available technology to detect additional zwitterionic, cationic, and anionic PFAS on surfaces and containers which previously contained Aqueous Film-Forming Foam (AFFF). Learn more here

Advanced Analytical and Forensic Tools: TOF, TOP Assay, Branched/Linear Isomers, and Non-Target Analysis

Current analytical methodologies measure a discrete list of 40 PFAS compounds on average. Many additional PFAS are not determined as discrete compounds by existing commercial methods, therefore we may be underestimating the PFAS mass present in the environment. As the investigation and treatment of sites contaminated with PFAS matures, there is a growing interest in determining the contributions of different sources to the overall contamination and understanding the true mass of PFAS present.

Eurofins has implemented several tools that illuminate additional pieces of the PFAS puzzle.

AFFF impacted samples analyzed by the TOP Assay have been shown to reveal an additional mass of PFAS compounds that can comprise of up to 70% of the fluorinated organics in the sample. The combination of the TOP analysis and the standard suite of PFAS compounds can give a more complete characterization of the PFAS contamination present.

Total Oxidizable Precursors (TOP) Assay

Water, soil, and sediment are treated with persulfate, hydroxide and heat to create a hydroxyl radical oxidation. An initial aliquot of each sample is analyzed for a suite of targeted PFAS compounds. Then a second portion of the sample is oxidized. When the oxidation is complete, the oxidized portion is extracted in the normal fashion for the same suite of PFAS compounds and then compared to the initial analysis. Increases in the concentrations in the Perfluorocarboxylic Acids (PFCAs) indicate the presence of oxidizable precursors which constitutes a portion of the hidden mass. Achievable detection limits are in the part per trillion (ppt) range.

Total Organofluorine (TOF)/(AOF)/(EOF)

The determination of total organic fluorine approaches quantitation of the unknown mass of PFAS from the angle of the fluorine content of a sample. With the use of combustion ion chromatography (CIC) a wide range of matrices are analyzed for Total Organic Fluorine (TOF), Total Adsorbable Organofluorine (AOF) in water, or Extractable Organic Fluorine (EOF) in solids. Achievable detection limits are in the part per billion (ppb) range.

Extensive Compound List

As AFFF and other PFAS sources have changed vendors and formulations over the years, the concentration and composition of PFAS in those products has also changed. As the number of targeted compounds increases, the likelihood of a unique identification increases. This is not to say that increasing from a list of 30 PFAS to a list of 70 PFAS will elucidate a point source, only increase the potential for additional and unique positive identifications. Achievable detection limits are in the part per trillion (ppt) range.

Branched/Linear/Total (BLT) PFAS Isomers

Separate results of the linear isomer and the sum of branched PFAS isomers for PFOA, PFOS, PFHxS, MeFOSAA, and EtFOSAA are possible. There are two main processes in which PFAS are created: Electrochemical and Telomerization. The electrochemical process produces both linear and branched isomers, but all are saturated, meaning that every carbon in the backbone is only bonded to another carbon and fluorine. The telomerization process results in mixed saturation but linear isomers only. These data reported separately can yield more information than a single value would.

Forensic PFOA

While BLT PFAS are nothing new for predominant PFAS researchers and laboratories alike, Eurofins is pleased to support a more refined BLT approach for PFOA. The characterization of PFOA in the environment has been under increased scrutiny and this advanced BLT analysis is designed specifically to support forensic investigations. The differentiator in this approach includes monitoring of additional ions of PFOA that delve into the speciation of branched PFOA isomers while unique calibration strategies facilitate the precise quantitation of linear to branched ratios of PFOA. Interested in learning more about Forensic PFOA? Click here.

Non-Target Analysis (NTA) by QTOF

While a long compound list and the ability to differentiate linear and branched isomers are powerful tools, there are estimated to be thousands of PFAS in-use or with legacy usage. As there are only analytical standards for a fraction of these compounds, additional instrumentation is needed to identify PFAS without commercially available standards. This task is best suited for Quadrupole-Time-Of-Flight Mass Spectrometry (QTOF-MS). This data results in exact mass, capable of matching identified compounds to a library of exact mass spectra (unique fragments of the original compound). Eurofins will utilize the NIST list for suspect screening or can compare results to a different list if provided. This allows for unknown compounds to be identified with chemical formula, name, and CAS number.