This study from Issue 15 of the Analytix Reporter utilized method EPA 533 for sample collection and sample preparation, employing Supelclean™ ENVI-WAX™ SPE cartridges for the subsequent LC-MS analysis on a dedicated Ascentis® Express PFAS HPLC column.
Per- and polyfluoroalkyl substances (PFAS) have been in use since the 1940s. Consisting of over 4700 different compounds, PFAS substances are used in almost every facet of modern life. The utility of these compounds resulted in their rapid adoption in consumer goods manufacturing. PFAS compounds can now be found in food packaging, cookware, cosmetics, stain and water repellants, firefighting foams, and are commonly used in many manufacturing processes. While incredibly useful, these compounds also carry a risk to health that we have only recently started to understand clearly.
Multiple regulatory methods, such as EPA 537 and 533, detail the extraction of PFAS analytes from drinking water using SPE cartridges followed by LC-MS/MS analysis. For EPA method 533, weak anion exchange (WAX) cartridges are specified and should contain 500 mg of the mixed-mode polymeric adsorbent. Supelclean™ ENVI-WAX™ SPE cartridges are direct equivalent to the specified SPE in EPA method 533. This application note demonstrates the extraction of 25 analytes from water using Supelclean™ ENVI-WAX™ SPE.
The procedure from EPA method 533 was followed for sample collection and sample preparation. Supelclean™ ENVI-WAX™ SPE 500 mg/6 mL cartridges were used with a Visiprep™ vacuum manifold for processing the samples. The samples were analyzed using an Agilent 6495C LC-MS/MS instrument. An Ascentis® Express PFAS HPLC Column, 2.7 µm, 15 cm x 2.1 mm was used as an analytical column. In addition, an Ascentis® Express PFAS Delay Column, 2.7 µm, 5 cm x 3.0 mm was used.
For full experimental and chromatography conditions, please refer to the full article.
RESULTS AND DISCUSSION
The background evaluation of the method using all SPE consumables and accessories resulted in excellent low background values (see Table 3 in the full article). The result for screening all compounds in the UHPLC-MS solvent was at or below the lower limit of detection (LLOD) of the LC-MS/MS instrument.
The workflow for EPA method 533 is presented in this article. All 25 compounds were recovered with acceptable accuracy and precision using Supelclean™ ENVI-WAX™ SPE cartridges, Visiprep™ vacuum manifold, Ascentis® Express PFAS columns and UHPLC-MS grade solvents. The background from all consumables and the LC system was low and acceptable for detecting low levels of PFAS analytes.
Find more information on PFAS testing at SigmaAldrich.com/PFAS
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