Conforming to EPA Methods 533/537, CE Instruments were tasked with tackling one of the forefront environmental contaminants now being targeted around the world. Poly(per-)-fluoroalkyl substances (PFAS), also known as 'forever chemicals', are suspected to cause diseases such as cancer and infertility in humans. PFAS are in are our food packaging, in our drinking water, and in our frying pans; it is almost impossible these days to avoid ingesting them. Whilst the UK has yet to adopt it's own official methodology, the EPA Methods 533/537 are being taken up almost ubiquitously, including in the UK. Further research is being undertaken to obtain their true health risks, countries are beginning to analyse and regulate their concentration in our drinking water. EPA Method 533 stipulates that we must be able to detect 18 PFAS molecules, which have a range of concentration reporting levels. The lowest of which is 1.6 ng/L.
Mandatory for this method is the use of a triple quadrupole mass spectrometer to detect the eluents from a HPLC. One such system is an Agilent 1200 LC paired with an Agilent Ultivo Mass Spectrometer (G6465A). This system also requires pure nitrogen gas; the most efficient supply being from a generator rather than a bottle due to the high flow rates required. Sample preparation is rigorous and requires solid phase extraction using a vacuum chamber. CE Instruments have sourced and prepared these hardware for a key customer, and images of them can be seen below.


The method is now in the final stages of development, where suitable limits of detection and quantification have been reached. The robustness of this method must now be tested to ensure long-term repeatability. A brief outline of our methodology can be found below:
Sample Collection, Preservation, and Storage: Proper techniques must be followed to collect and preserve water samples to prevent contamination and degradation .
Reagent Preparation: Preparation of necessary reagents and standards is crucial for the analysis. This includes ensuring that all reagents meet the required specifications .
Initial Demonstration of Capability (IDC): Laboratories must demonstrate their ability to perform the method accurately in reagent water before analysing field samples. This includes assessing precision and accuracy .
Calibration and Standardization: Calibration of the mass spectrometry (MS) system and initial analyte calibration must be performed before conducting the IDC and analysing samples. This ensures that the instrument is functioning correctly .
Sample Extraction: The method involves an anion exchange solid phase extraction process to isolate the target analytes from the water samples .
Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS): The extracted samples are then analysed using LC-MS/MS, which allows for the detection and quantification of per- and polyfluoroalkyl substances .
Data Analysis and Calculations: After analysis, the data must be processed and calculated to determine the concentration of the analytes in the samples .
Quality Control: Ongoing quality control measures must be implemented to ensure the reliability of the results throughout the analysis process .
Contact CE Instruments for similar hardware and method support today. We are a smaller company that has the time to work closely with you, our valued customers.
Appendix: Below are some additional images from the LCMS setup process.


Authored by James Dobie MSc, Applications Engineer at CE Instruments
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