Source Fingerprinting of PFOA via Full- and Intramolecular Stable Isotope Ratios of Carbon Using Orbitrap-IRMS
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Remediation approaches for reducing environmental loading of perfluoroalkyl and polyfluoroalkyl substances (PFAS) require the ability to track PFAS origin sources. One common source attribution method for environmental contaminants is stable isotope analysis, with magnetic sector isotope ratio mass spectrometry (IRMS) being the workhorse for making these measurements. However, relatively large sample requirements and the requisite deconstruction of analytes to simple gases (e.g., CO 2 ) inhibit the application of IRMS to PFAS in environmental contexts, where even trace PFAS concentrations can exhibit toxicological effects, and decomposition of PFAS yields instrument-degrading HF. To circumvent these limitations, we developed an electrospray ionization Orbitrap-IRMS method to determine stable carbon isotope ( 13 C) ratios of PFAS with reduced sample quantities, without producing HF, and with the additional capability of performing intramolecular isotope ratio measurements for increased sample discrimination potential. We demonstrate this approach using perfluorooctanoic acid (PFOA) as a model compound. We collected twenty-three samples of neat, commercially available PFOA with different lot numbers from 15 different suppliers and determined that the full molecule stable carbon isotope ratios span ∼25‰ with a measurement precision of 0.7‰. The stable isotope ratios of the decarboxylated fragment of PFOA span ∼28‰ with a measurement precision of 0.2‰. Of the 253 possible pairwise comparisons between the samples, 230 are significantly different based on the combined full and intramolecular isotopic signatures. The isotopic analyses suggest a correlation with the PFOA synthesis method. Our results highlight the potential of Orbitrap-IRMS as a forensic tool for the source attribution of PFAS contaminants.
Source: Analytical Chemistry
Institution: Michigan State University
Language: English
Subfield: Environmental Chemistry
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: G4067550966, PURPOSE:THE PURPOSE OF THE GRANT IS TO TEST LC-HIGH RESOLUTION MASS SPECTROMETRY FOR ISOTOPIC PROFILING OF CARBON AND SULFUR ISOTOPES AS PART OF PER AND POLYFLUORINATED ALKYL SUBSTANCES (PFAS). THIS INFORMATION MAY BE USEFUL FOR PERFORMING SOURCE APPORTIONMENT OF PFAS CONTAMINATION. TO ACCOMPLISH THIS TASK, THE INVESTIGATORS ARE SEEKING FUNDS TO PURCHASE A THERMO EXPLORIS 240 ORBITRAP. THE INVESTIGATORS ARE ALSO SEEKING A SMALL SALARY, SUPPLY AND TRAVEL BUDGET TO SUPPORT THE INSTRUMENT PURCHASE AND EXECUTION OF THE PROJECT.ACTIVITIES TO BE PERFORMED:THE MAIN ACTIVITY TO BE PERFORMED ONCE THE INSTRUMENT IS PURCHASED IS TO MEASURE CARBON AND SULFUR ISOTOPES OF PFAS IN STANDARD MIXTURES USING THE ORBITRAP AS A PROOF OF CONCEPT.EXPECTED OUTCOMES:IF SUCCESSFUL, THE APPROACH COULD BE VALUABLE TO UNDERSTANDING CONTAMINATION SOURCES OF PFAS IN THE ENVIRONMENT. ORBITRAP INSTRUMENTS ARE BECOMING MORE COMMON IN LABORATORIES, HENCE THE APPROACH MAY HAVE WIDER APPEAL DUE INSTRUMENT AVAILABILITY.INTENDED BENEFICIARIES:PFAS IN THE ENVIRONMENT CAN ORIGINATE FROM DIFFERENT SOURCES WHERE THE SOURCES MAY BE DIFFERENT MANUFACTURERS. SORTING OUT HOW MUCH EACH SOURCE IS ATTRIBUTABLE TO WHICH MANUFACTURER IS HIGHLY VALUABLE FOR ASSIGNING RESPONSIBILITY. THERE ARE OTHER APPLICATIONS OF THE ISOTOPIC PROFILING TECHNIQUE TO SUCH AREAS AS EVALUATING PFAS SOURCES IN THE INDOOR ENVIRONMENT, FOOD CONTAMINATION AND DRINKING WATER.SUBRECIPIENT ACTIVITIES:THE RECIPIENT DOES NOT INTEND TO SUBAWARD FUNDS., G82352454
OpenAlex ID: W4417305118