1633 Draft No More! 

With the successful completion of the multi-laboratory validation, EPA 1633 method, developed by SGS, has reached its final stage. This is a significant milestone not only for SGS as the leading experts in PFAS analysis but also for the entire environmental testing industry.  

Following rigorous multi-laboratory validation, EPA 1633 now stands as the comprehensive reference method for PFAS in non-potable aqueous, solid, and tissue samples. This success shows that the method is robust and has been successfully performed at multiple laboratories.   

What does this mean for you? 

  1. Finalized Specifications: The method specifications for solids and tissues have been solidified, complementing the previously finalized specifications for aqueous samples in Draft 4. This ensures consistency and clarity in testing protocols, providing confidence in the accuracy of results.
  2. Accreditation Updates: While the final version of EPA 1633 supersedes all other versions, updating accreditations to align with this standard will take some time. At SGS, we’re already ahead of the curve, with our Orlando and SGS AXYS Sidney, BC laboratories leading the charge in updating accreditations to EPA 1633, with the Dayton laboratory set to follow suit in the next quarter. Major data users, including the US Department of Defense, have shown flexibility in accreditation transitions, recognizing the minor differences and providing ample time for compliance.
  3. Streamlined Processes: For NPDES permitting purposes, the requirement for laboratory duplicates has been eliminated, simplifying the testing process without compromising accuracy. Similarly, as typical with isotope dilution 1600 series methods, MS/MSDs are no longer required, further streamlining operations.

After the Update 

There have been some minor changes in procedure, criteria and increased performance-based flexibility after the update.   

  • Procedures to allow for aqueous samples with higher than 50 mg solids. The method provides flexibility based on prior approval to centrifuging the sample, decanting the aqueous phase and reporting as two separate samples. The method provides for either a visual examination OR a TSS and either is acceptable.   
  • Procedures to allow for the use of carbon cartridges for extract cleanup building on earlier draft versions. 
  • A floor of 5% has been set for EIS recovery, below which data is reported as an estimated value.   
  • Instrument sensitivity checks are now required at the beginning of each analytical sequence. 
  • Holding time for tissues if frozen within 48 hours of collection now begins only when processing starts and not at time of collection.   
  • Dilutions of high-level samples. The method now includes an explicit dilution factor (DF) in the calculations and specifies that dilutions can be performed only for the analytes exceeding the range. The requirement not to exceed a 10X dilution has been removed as long as EIS recoveries meet all signal and retention time requirements. 
To find out how we can best help you with your PFAS analysis, call +1 800 329 0204 or email PFAS.Expert@sgs.com. We look forward to hearing from you soon.