The US EPA has developed a draft Method 1633, which is a comprehensive and validated method for detecting 40 different PFAS compounds across various matrices, including wastewater. This method is particularly robust and standardized, ensuring reliable PFAS monitoring in non-potable water, which is crucial for protecting public health.
Here are the key aspects of EPA Method 1633:
1. Aqueous samples are spiked with isotopically labeled standards, extracted using solid-phase extraction (SPE) cartridges, and cleaned up using carbon before analysis.
2. Sample extracts are analyzed using Liquid Chromatography coupled with Tandem Mass Spectrometry (LC/MS/MS) in multiple reaction monitoring (MRM) mode.
3. Concentrations are determined by isotope dilution or extracted internal standard quantification, using isotopically labeled compounds added to the samples before extraction.
4. The use of isotope dilution and extracted internal standard quantification helps correct for any losses during sample extraction, cleanup, and concentration.
5. Isotopically labeled compound recoveries are compared to non-extracted internal standards to ensure analytical quality and address matrix effects that could otherwise cause measurement bias.
By following this method, you can ensure comprehensive and accurate PFAS testing in wastewater, providing reliable data essential for environmental monitoring and public health protection.