Presentation Profile
True Internal Calibration Models for EPA Method 1633A and Method 533
Currently Scheduled: 10/14/2026 - 1:00 PM - 2:00 PM
Room: Exhibit Hall Entrance
Main Author
Xiangqiu Liang - City of Houston
Abstract:
Linear regression fitting in PFAS internal calibration is challenging due to the complexity of PFAS chemistry, matrix effects, and the need for high precision at trace levels. We have been working with CIL to improve stable isotope labeled standards (SIL) and have added additional SIL to EPA 1633 and EPA 533 methods. The methods contain little guidance for the true internal standard calibration. This presentation attempts to clarify the process. The internal standard calibration involves adding isotope labeled standards (EIS/NIS, EPA1633A; IPS/IDS, EPA533) to native compounds. Comparing how the detector responds to the native compound relative to the labeled standard.
