Thermal desorption – gas chromatography – mass spectrometry (TD-GC-MS) analysis of PFAS used in food contact materials

Food Additives & Contaminants Part A, Journal Year: 2024, Volume and Issue: 41(9), P. 1099 - 1117

Published: July 10, 2024

Per- and polyfluoroalkyl substances (PFAS) are used in food contact materials (FCMs), e.g. as production aids the fabrication of PTFE based coatings for kitchenware or additives paper board. Growing concerns about environment health related to PFAS have led an increasing interest monitoring levels FCMs well their migration into food. In this study, method development analysis by thermal desorption – gas chromatography mass spectrometry (TD-GC-MS) was done. addition fluorotelomer alcohols (FTOHs), which only commonly analysed GC-MS, it proven that perfluorocarboxylic acids (PFCAs) per- polyfluoroether carboxylic (PFECAs) thermolysis products, perfluoroethers (PFEs) perfluoroalkenes, can be GC-MS without prior derivatization. Screening PFCAs FTOHs possible electron impact ionization (EI) using group specific SIM fragments. Confirmation identity has been done EI scans chemical (CI) measurements. LODs (limits detection) PFCAs, PFECAs TD-GC-MS instrument were low pg range. Thermal degradation during measurement investigated.

Language: Английский

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Headgroup Dependence and Kinetic Bottlenecks of Gas-Phase Thermal PFAS Destruction

ACS ES&T Engineering, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 2, 2025

Recent studies of thermal PFAS destruction have reported seemingly incoherent temperatures and products, often because decomposition pathways are highly dependent on the respective experimental system. Here, we applied accurate DLPNO–CCSD(T) coupled cluster calculations to isolate identify major processes during in gas phase, with relevance incineration, oxidation, other treatment technologies which their volatile products desorb into phase. All investigated perfluoroalkyl acids decompose via unimolecular headgroup loss, either through HF elimination or homolytic bond cleavage as a function type. In contrast, all fluorotelomers undergo initial hydrogen abstraction from characteristic C2H4 moiety by hydroxyl radicals under representative incineration conditions, followed radical decomposition. Subsequent formation perfluoroalkanes, including CF4, can then be prevented supplying sufficient donors such hydrocarbon fuel water well scavenging released fluorine. This leads generation stable 1H-perfluoroalkanes. While parent proceeds at gas-phase ≤700 °C, carbon–carbon 1H-perfluoroalkanes requires up ∼950 °C 2 s residence time, making this step kinetic bottleneck way complete mineralization.

Language: Английский

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Accurate Enthalpies of Formation for PFAS from First-Principles: Combining Different Levels of Theory in a Generalized Thermochemical Hierarchy

ACS Physical Chemistry Au, Journal Year: 2024, Volume and Issue: 4(3), P. 247 - 258

Published: Feb. 27, 2024

The enthalpies of formation are computed for a large number per- and poly fluoroalkyl substances (PFAS) using connectivity-based hierarchy (CBH) approach. A combination different electronic structure methods used to provide the reference data in hierarchical manner. ANL0 method, conjunction with active thermochemical tables, provides smaller species subchemical accuracy. Coupled-cluster theory explicit correlations compute intermediate species, based upon results. For largest PFAS, including perfluorooctanoic acid (PFOA) heptafluoropropylene oxide dimer (GenX), coupled-cluster local is used. sequence homodesmotic reactions proposed by CBH determined automatically new open-source code, AutoCBH. results first reported majority species. convergence analysis global uncertainty quantification confirm that at 0 K should be accurate within ±5 kJ/mol. This approach not limited but can applied many chemical systems.

Language: Английский

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Thermal Transformations of Perfluorooctanoic Acid (PFOA): Mechanisms, Volatile Organofluorine Emissions, and Implications to Thermal Regeneration of Granular Activated Carbon

Journal of Hazardous Materials, Journal Year: 2024, Volume and Issue: 479, P. 135737 - 135737

Published: Sept. 3, 2024

Language: Английский

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Review of per- and poly-fluoroalkyl treatment in combustion-based thermal waste systems in the United States

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 932, P. 172658 - 172658

Published: April 22, 2024

Language: Английский

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Formation of Products of Incomplete Destruction (PID) from the Thermal Oxidative Decomposition of Perfluorooctanoic Acid (PFOA): Measurement, Modeling, and Reaction Pathways

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(27), P. 5362 - 5373

Published: June 27, 2024

The thermal decomposition of perfluorooctanoic acid (PFOA) under oxidative conditions was investigated using air (O2) and N2O as oxidants over temperatures ranging from 400 to 1000 °C in an α-alumina reactor. In the presence air, PFOA found decompose into perfluorohept-1-ene (C7F14) perfluoroheptanoyl fluoride (C7F14O) addition HF, CO, CO2. At above 800 °C, both C7F14 C7F14O were no longer detected. A comprehensive analysis reaction mechanisms through quantum chemical kinetic modeling combination with experimental observations utilized identify key pathways. Quantum led conclusion that oxygen atoms are crucial decomposing perfluoroalk-1-enes, especially stable (C7F14). Under conditions, it significant quantities C2F6 CF4 formed. Further suggests O facilitate formation volatile fluorinated compounds (VFCs) such tetrafluoromethane (CF4) hexafluoroethane (C2F6), particularly at higher temperatures. By elucidating these reactions, improved understanding potential products incomplete combustion (PICs) or destruction (PIDs) is made.

Language: Английский

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Predicting The Thermal Decomposition Behaviour of Perfluorooctane Sulfonamidoacetic Acid (FOSAA): An Emerging Heteroatomic PFAS

Journal of environmental chemical engineering, Journal Year: 2025, Volume and Issue: unknown, P. 115640 - 115640

Published: Jan. 1, 2025

Language: Английский

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Direct measurement of fluorocarbon radicals in the thermal destruction of perfluorohexanoic acid using photoionization mass spectrometry

Science Advances, Journal Year: 2025, Volume and Issue: 11(9)

Published: Feb. 28, 2025

Thermal destruction is a critical cornerstone of addressing the rampant contamination natural resources with per- and polyfluoroalkyl substances (PFAS). However, grave concerns associated stack emissions from incineration exist because mechanistic studies have thus far relied on ex situ analyses end products theoretical calculations. Here, we used synchrotron-based vacuum ultraviolet photoionization mass spectrometry to study pyrolysis representative PFAS—perfluorohexanoic acid—and provide direct evidence fluorocarbon radicals intermediates. A key reaction pathway perfluorocarboxylic acids ketenes via acyl fluorides proposed. We furthermore propose CF 2 /CF 3 radical–centered mechanisms explain their roles in formation other that may form full-scale incinerators. These results not only unveiled role intermediates thermal PFAS decomposition recombination but also unique insight into improving safety viability industrial incineration.

Language: Английский

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Thermal Decomposition of Atrazine and its Toxic Products

Environmental Science Processes & Impacts, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

At temperatures above 400 °C, the thermal decomposition of ATZ produces highly toxic chemicals including hydrogen cyanide (HCN), thus posing environmental and health risks.

Language: Английский

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Unraveling Hidden Infrared Spectral Signatures in PFAS Thermal Degradation with Two-Dimensional Correlation Spectroscopy

Environmental Science & Technology Letters, Journal Year: 2025, Volume and Issue: unknown

Published: April 4, 2025

Language: Английский

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