Ming-Gao Xu,Hao Ma,Xiang Deng,Huiting Bian,Long Zhao,Alexander K. Lemmens,Nureshan Dias,Musahid Ahmed,Anthony K. Rappé,Eric M. Kennedy,Michael Stockenhuber,John A. Lucas,Jens Blotevogel,Wenchao Lu
TFA and DFA decompose via HF loss starting from 200 °C. • Alumina surfaces enhance the thermal mineralization of TFA. • Alumina surfaces promote CF 2 recombination to C 2 F 4 and perfluorocyclopropane as PIDs. • Hydrogenation of TFA reduces persistent intermediates formation. • Perfluorocyclopropane may serve as an indicator of surface-mediated PIDs. While thermal destruction remains one of the most effective treatments for ultrashort-chain per- and polyfluoroalkyl substances (PFAS) such as trifluoroacetic acid (TFA) at full scale, their evolution during incineration processes remains poorly understood, particularly those promoted by material surfaces in contact with the PFAS stream. Here we resolve the intrinsic and surface-mediated mechanisms of the pyrolysis of TFA and its non-PFAS analogue difluoroacetic acid (DFA) using synchrotron vacuum-ultraviolet photoionization mass spectrometry. Both compounds decompose primarily via HF elimination followed by decarboxylation or decarbonylation. Surprisingly, alumina surfaces facilitate the elimination of HF from TFA, but promote the formation of tetrafluoroethylene and perfluorocyclopropane as products of incomplete destruction (PIDs) from a bottom-up growth of CF 2 . These findings suggest that perfluorocyclopropane may serve as a promising indicator of surface-catalyzed recombination reactions during full-scale incineration. In contrast, DFA generates hydrogen-containing intermediates that undergo rapid secondary reactions, suppressing the formation of PIDs and enhancing overall incinerability. Our findings provide benchmark mechanistic insight into ultrashort-chain PFAS decomposition and call for systematic evaluation of surface effects that promote PID formation. Download: Download high-res image (116KB) Download: Download full-size image
Trifluoroacetic acid (TFA) is considered a per- and polyfluoroalkyl substance (PFAS) by the European Chemicals Agency, yet its potential reproductive toxicity remains poorly understood. Here, we investigated the testicular effects and underlying mechanisms of TFA exposure in adolescent male mice. Based on environmental and potential dietary exposure levels, available toxicological and risk-assessment information, and the findings of our preliminary experiment, mice were orally administered TFA at 0.0042, 0.042, 0.42, or 4.2 mg/kg/day for 21 days, followed by a 7-day recovery period. Residual TFA remained detectable in the serum and testes after the recovery period, and doses ≥ 0.042 mg/kg/day induced Leydig cell and spermatogenic cell damage, accompanied by reduced testosterone levels. TFA exposure also increased testicular oxidative stress (OS) and activated the ribotoxic stress response (RSR) and NLRC5-PANoptosome-related signaling. These cellular stress responses were associated with activation of PANoptosis-related pathways, involving pyroptosis, apoptosis, and necroptosis, and ultimately contributed to testicular tissue injury and impaired testicular function. Collectively, our findings demonstrate that TFA exposure at environmentally and risk-assessment-relevant levels induces testicular injury in adolescent male mice and identify a potential mechanistic link between OS, RSR, NLRC5-PANoptosome-related signaling, and PANoptosis. These findings provide new insights into the reproductive toxicity of TFA and highlight the need for further evaluation of its potential health risks.
Shuyi Li,Qian Wu,Fangfang Yin,Zhenzhou Zhu,Jingren He,Francisco J. Barba
Over the last years, inulin, a fructan mixture consisting of oligosaccharides and polysaccharides, has attracted more and more attention from both food industry and researchers, due to its unique functional properties as a natural resource. Therefore, there is an increased interest in the extraction and quantification of inulin for its valorization from inulin rich plants, wastes and by-products. In this work, ultrasonic treatment was applied for inulin extraction, observing a great impact of extraction temperature and ultrasonic power on the inulin content in the obtained extracts. A combined process including trifluoroacetic acid (TFA)-assisted hydrolysis and analysis with high performance liquid chromatography equipped with evaporative light scattering detector (HPLC-ELSD) was developed to quantify inulin content. The effect of hydrolysis parameters was investigated, obtaining the optimal conditions after using TFA at a concentration of 1 mg/mL, hydrolysis temperature of 90 °C, and hydrolysis duration of 60 min. The good linearity (>0.995), precision, recovery (100.27%), and stability obtained during the validation process showed that this developed method allows the quantification of total inulin content in the samples analyzed. This combined method may also contribute to the investigation of the functional properties of inulin (e.g., as prebiotic).
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