ASTM D8421-24 PDF
1.1This test method covers the determination of per- and polyfluoroalkyl substances (PFASs) in aqueous matrices using liquid chromatography (LC) and detection with tandem mass spectrometry (MS/MS). These analytes are co-solvated by a 1+1 ratio of sample and methanol then qualitatively and quantitatively determined by this test method. Quantitation is by selected reaction monitoring (SRM) or sometimes referred to as multiple reaction monitoring (MRM).
1.2The method detection limit (MDL) (see Note 1) and reporting range (see Note 2) for the target analytes are listed in Table 1. The target concentration for the reporting limit for this test method is an integer value that is calculated from the concentration from the lowest standard from the final volume of the prepared sample. This value may be lower than the calculated MDL due to sporadic PFAS hits due to PFAS contamination in consumables/collection tools used during sample collection and preparation. All samples should be taken at a minimal as duplicates in order to compare the precision between the two prepared samples to help ensure the concentration/positive result is reliable.
Note 1:The MDL is determined following the Code of Federal Regulations (CFR), 40 CFR Part 136, Appendix B utilizing dilution and filtration. A detailed process determining the MDL is explained in the reference and is beyond the scope of this test method.
Note 2:Injection volume variations, and sensitivity of the instrument used will change the reporting limit and ranges.
1.2.1Recognizing continual advancements in the sensitivity of instrumentation, advancements in column chromatography and other processes not recognized here, the reporting limit may be lowered assuming the minimum performance requirements of this test method at the lower concentrations are met.
1.2.2Depending on data usage, you may modify this test method but limit to modifications that improve performance while still meeting or exceeding the method quality acceptance criteria. Modifications to the solvents, ratio of solvent to sample, or shortening the chromatographic run simply to save time are not allowed. Use Practice E2935 or similar statistical tests to confirm that modifications produce equivalent results on non-interfering samples. In addition, use Guide E2857 or equivalent statistics to re-validate the modified test.
1.2.3Analyte detections between the method detection limit and the reporting limit are estimated concentrations. The reporting limit is based upon the concentration of the Level 1 calibration standard as shown in Table 5.
1.3The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
