Transformation of Fluorotelomer Carboxylic Acids and the Development of Methods to Analyze Total Fluorine in Complex Environmental Matrices
Bibliographic record
Abstract
Per- and polyfluoroalkyl substances (PFAS) represent a class of synthetic compounds widely utilized in consumer products and prevalent across various environmental matrices. They are typically analyzed individually or comprehensively as a chemical family, primarily identified by their abundant fluorine content. Over the last two decades, there has been a notable trend towards utilizing partially fluorinated PFAS, which emulate the characteristics of fully fluorinated terminal PFAS but are subject to less stringent regulatory oversight. To provide context for experimental work, Chapter 1 introduces the dissertation’s objectives and overarching research questions, while Chapter 2 presents a comprehensive review of PFAS and fluorine analysis techniques. This review highlights current methodological strengths, limitations, and key parameters, laying the groundwork for the two primary research projects. The first project, described in Chapter 3, investigates the ambient transformation of PFAS precursors. It begins by exploring an elimination pathway under controlled laboratory conditions using a base, establishing a baseline understanding of the reaction. A similar experiment is then conducted using a consumer-grade cleaning agent, demonstrating that comparable transformation is possible in indoor environments. Using both targeted and non-targeted analysis, the study reveals challenges in accurately assessing PFAS composition and species abundance due to the transformation of precursors to terminal PFAS. The second project, detailed in Chapter 4, focuses on developing analytical methods for total fluorine (TF) detection using Particle-Induced Gamma-ray Emission (PIGE) spectrometry, a relatively novel technique in PFAS analysis that lacks standardized protocols for this chemical class. Despite this, PIGE demonstrated promising results comparable to those of established analytical instruments. Successful TF analysis methods were applied to various matrices relevant to PFAS treatment, including granular activated carbon, Ottawa sand, and brass. Finally, Chapter 5 synthesizes the dissertation’s findings, discusses broader implications, and identifies opportunities for future PFAS research.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".