Non-targeted screening
The analysis of PFAS compounds typically requires the use of LC-MS/MS systems. However, as more PFAS compounds are discovered and more complex matrices are tested, both regulated and unregulated analytical methods will need to adapt. The non- targeted analysis allows the discovery of novel PFAS in the environment. EPA published Method 1621 in January 2024, which is a new screening for the Determination of Adsorbable Organic Fluorine (AOF) in Aqueous Matrices by Combustion Ion Chromatography (CIC) . This method provides an accumulative measurement of chemical substances that contain C-F bonds. The method measures organofluorine compounds f rom PFAS and non-PFAS fluorinated compounds that can be retained on at least 80 mg of granular activated carbon (GAC). The result is reported as the concentration of fluoride (F-) in the sample. EPA advises that this method may be used to estimate the aggregate contributions of the organofluorine compounds present in the sample. It advises that the numerical results generated by this method are not expected to be as accurate or precise as those from targeted methods for PFAS. [20, 21] In addition, Extractable Organic Fluorine (EOF) can be used. In both the cases of AOF and EOF, the inorganic fluorine must be removed.
1 1
Made with FlippingBook. PDF to flipbook with ease