Abstract
Fluorine free analogues of three commercially available rigid contact lens materials were prepared by replacing the fluorinated component, hexafluoroisopropyl methacrylate (HFPM), with the widely used, non-fluorinated monomers methyl methacrylate (MMA) and 3-methacryloxypropyltris-(trimethylsiloxy)silane (TRIS). The properties of the commercial materials and analogues were measured and compared. The oxygen permeabilities of the MMA analogues were found to be significantly lower than those of the commercial materials, decreasing by 87 % on average, while the TRIS analogues lacked sufficient hardness, dimensional stability and lipid deposit resistance to be viable for use in rigid contact lenses. Analogues prepared using a 1:1 mixture of MMA and TRIS had the best overall combination of properties, but were still on average 47 % less permeable to oxygen and also significantly less resistant to lipid deposition. The analogues prepared in this study did not adequately replicate the performance of marketed, fluorine containing rigid contact lens materials. These observations give an indication of the challenges that would face contact lens material manufacturers in preparing rigid lens polymers without the use of fluorinated species. A reduction in effectiveness would be almost inevitable, and would be expected to have a negative impact on the safety and eye health of rigid contact lens patients.
Acknowledgements
The authors thank Dr Matthew Rowland for providing the lipid deposition methodology.
-
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
-
Research funding: None declared.
-
Conflict of interest statement: The authors declare that they have no conflicts of interest regarding this article.
References
1. Downie, L. E., Lindsay, R. G. Contact lens management of keratoconus. Clin. Exp. Optom. 2015, 98, 299–311; https://doi.org/10.1111/cxo.12300.Search in Google Scholar PubMed
2. Manchester University, NHS Foundation, Trust. Contact Lenses for Keratoconus. Information for Patients, REH 210 TIG 135/14, Reviewed 2019. https://mft.nhs.uk/app/uploads/sites/2/2018/04/REH-210.pdf (accessed Jul 20, 2022).Search in Google Scholar
3. Leung, K. K. Y. RGP fitting philosophies for keratoconus. Clin. Exp. Optom. 1999, 82, 230–235; https://doi.org/10.1111/j.1444-0938.1999.tb06653.x.Search in Google Scholar PubMed
4. Rathi, V. M., Mandathara, P. S., Dumpati, S. Contact lens in keratoconus. Indian J. Ophthalmol. 2013, 61, 410–415; https://doi.org/10.4103%2F0301-4738.116066.10.4103/0301-4738.116066Search in Google Scholar PubMed PubMed Central
5. Barnett, M., Courey, C., Fadel, D., Lee, K., Michaud, L., Montani, G., van der Worp, E., Vincent, S. J., Walker, M., Bilkhu, P., Morgan, P. B. BCLA CLEAR – Scleral lenses. Contact Lens Anterior Eye 2021, 44, 240–269; https://doi.org/10.1016/j.clae.2021.02.003.Search in Google Scholar PubMed
6. Asghari, B., Brocks, D., Carrasquillo, K. G., Crowley, E. OSDI outcomes based on patient demographic and wear patterns in prosthetic replacement of the ocular surface ecosystem. Clin. Optom. 2022, 14, 1–12; https://doi.org/10.2147/OPTO.S337920.Search in Google Scholar PubMed PubMed Central
7. Sarver, M. D., Polse, K. A., Harris, M. G. Patient responses to gas-permeable hard (Polycon) contact lenses. Am. J. Optom. Physiol. Opt. 1977, 54, 195–200; https://doi.org/10.1097/00006324-197704000-00001.Search in Google Scholar PubMed
8. Michaud, L., van der Worp, E., Brazeau, D., Warde, R., Giasson, C. J. Predicting estimates of oxygen transmissibility for scleral lenses. Contact Lens Anterior Eye 2012, 35, 266–271; https://doi.org/10.1016/j.clae.2012.07.004.Search in Google Scholar PubMed
9. Compañ, V., Oliveira, C., Aguilella-Arzo, M., Mollá, S., Peixoto-de-Matos, S. C., González-Méijome, J. M. Oxygen diffusion and edema with modern scleral rigid gas permeable contact lenses. Investig. Ophthalmol. Vis. Sci. 2014, 55, 6421–6429; https://doi.org/10.1167/iovs.14-14038.Search in Google Scholar PubMed
10. Dhallu, S. K., Huarte, S. T., Bilkhu, P. S., Boychev, N., Wolffsohn, J. S. Effect of scleral lens oxygen permeability on corneal physiology. Optom. Vis. Sci. 2020, 97, 669–675; https://doi.org/10.1097/opx.0000000000001557.Search in Google Scholar
11. Lin, M. C., Graham, A. D., Fusaro, R. E., Polse, K. A. Impact of rigid gas-permeable contact lens extended wear on corneal epithelial barrier function. Investig. Ophthalmol. Vis. Sci. 2002, 43, 1019–1024.Search in Google Scholar
12. Harvitt, D. M., Bonanno, J. A. Re-evaluation of the oxygen diffusion model for predicting minimum contact lens Dk/t values needed to avoid corneal anoxia. Optom. Vis. Sci. 1999, 76, 712–719; https://doi.org/10.1097/00006324-199910000-00023.Search in Google Scholar PubMed
13. Wolffsohn, J. S., Calossi, A., Cho, P., Gifford, K., Jones, L., Li, M., Lipener, C., Logan, N. S., Malet, F., Matos, S., González-Méijome, J. M., Nichols, J. J., Orr, J. B., Santodomingo-Rubido, J., Schaefer, T., Thite, N., van der Worp, E., Zvirgzdina, M. Global trends in myopia management attitudes and strategies in clinical practice. Contact Lens Anterior Eye 2016, 39, 106–116; https://doi.org/10.1016/j.clae.2016.02.005.Search in Google Scholar PubMed
14. Holden, B. A., Fricke, T. R., Wilson, D. A., Jong, M., Naidoo, K. S., Sankaridurg, P., Wong, T. Y., Naduvilath, T. J., Resnikoff, S. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmology 2016, 123, 1036–1042; https://doi.org/10.1016/j.ophtha.2016.01.006.Search in Google Scholar PubMed
15. World Health Organisation. The Impact of Myopia and High Myopia, 2015. https://myopiainstitute.org/wp-content/uploads/2020/10/Myopia_report_020517.pdf (accessed Jul 20, 2022).Search in Google Scholar
16. Modjtahedi, B. S., Ferris, F. L., Hunter, D. G., Fong, D. S. Public health burden and potential interventions for myopia. Ophthalmology 2018, 125, 628–630; https://doi.org/10.1016/j.ophtha.2018.01.033.Search in Google Scholar PubMed
17. Flitcroft, D. I. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog. Retin. Eye Res. 2012, 31, 622–660; https://doi.org/10.1016/j.preteyeres.2012.06.004.Search in Google Scholar PubMed
18. Jensen, H. Myopia in teenagers. Acta Ophthalmol. Scand. 2009, 73, 389–393; https://doi.org/10.1111/j.1600-0420.1995.tb00294.x.Search in Google Scholar PubMed
19. Saw, S. M., Gazzard, G., Shih-Yen, E. C., Chua, W. H. Myopia and associated pathological complications. Ophthalmic Physiol. Opt. 2005, 25, 381–391; https://doi.org/10.1111/j.1475-1313.2005.00298.x.Search in Google Scholar PubMed
20. Bullimore, M. A., Johnson, L. A. Overnight orthokeratology. Contact Lens Anterior Eye 2020, 43, 322–332; https://doi.org/10.1016/j.clae.2020.03.018.Search in Google Scholar PubMed
21. Vincent, S. J., Cho, P., Chan, K. Y., Fadel, D., Ghorbani-Mojarrad, N., González-Méijome, J. M., Johnson, L., Kang, P., Michaud, L., Simard, P., Jones, L. BCLA CLEAR – orthokeratology. Contact Lens Anterior Eye 2021, 44, 240–269; https://doi.org/10.1016/j.clae.2021.02.003.Search in Google Scholar PubMed
22. Walline, J. J., Jones, L. A., Sinnott, L. T. Corneal reshaping and myopia progression. Br. J. Ophthalmol. 2009, 93, 1181–1185; https://doi.org/10.1136/bjo.2008.151365.Search in Google Scholar PubMed
23. Chen, C., Cheung, S. W., Cho, P. Myopia control using toric orthokeratology (TO-SEE Study). Invest. Opthalmol. Vis. Sci. 2013, 54, 6510–6517; https://doi.org/10.1167/iovs.13-12527.Search in Google Scholar PubMed
24. Cho, P., Cheung, S. W. Retardation of myopia in orthokeratology (ROMIO) study: a 2-year randomized clinical trial. Invest. Opthalmol. Vis. Sci. 2012, 53, 7077–7085; https://doi.org/10.1167/iovs.12-10565.Search in Google Scholar PubMed
25. Santodomingo-Rubido, J., Villa-Collar, C., Gilmartin, B., Gutiérrez-Ortega, R., Sugimoto, K. Long-term efficacy of orthokeratology contact lens wear in controlling the progression of childhood myopia. Curr. Eye Res. 2016, 42, 713–720; https://doi.org/10.1080/02713683.2016.1221979.Search in Google Scholar PubMed
26. Caroline, P. J., Norman, C. W. History of contact lenses – the story of plastic and PMMA. Contact Lens Spectrum. https://www.clspectrum.com/issues/2022/april-2022/history-of-contact-lenses (accessed Jul 20, 2022).Search in Google Scholar
27. Sweeney, D. F. Corneal exhaustion syndrome with long-term wear of contact lenses. Optom. Vis. Sci. 1992, 69, 601–608; https://doi.org/10.1097/00006324-199208000-00002.Search in Google Scholar PubMed
28. Zimmerman, A. B. Contemporary CL complications. Contact Lens Spectrum. https://www.clspectrum.com/issues/2018/december-2018/contemporary-cl-complications (accessed Jul 20, 2022).Search in Google Scholar
29. McMahon, T. T., Polse, K. A., McNamara, N., Viana, M. A. Recovery from induced corneal edema and endothelial morphology after long-term PMMA contact lens wear. Optom. Vis. Sci. 1996, 73, 184–188; https://doi.org/10.1097/00006324-199603000-00010.Search in Google Scholar PubMed
30. Bruce, A. S., Brennan, N. A., Lindsay, R. G. Diagnosis and management of ocular changes during contact lens wear, Part II. Clin. Signs Ophthalmol. 1996, 17, 2–11.Search in Google Scholar
31. Giedd, B. Understanding the nuances of contact lens materials. Contact Lens Spectrum. https://www.clspectrum.com/issues/1999/july-1999/understanding-the-nuances-of-contact-lens-material (accessed Jul 20, 2022).Search in Google Scholar
32. Phillips, A. J., Speedwell, L., Eds. Contact Lenses; Butterworth-Heinemann: Oxford, UK, 1997, 4th ed., pp. 323–327.Search in Google Scholar
33. Ehlers, W., Suchecki, J., Steinemann, T. L., Donshik, P. Contact lens related complications. In Ophthalmology; Yanoff, M., Duker, J. S., Eds., 4th ed.; Elsevier Health Sciences: Edinburgh, London, New York, Oxford, Philadelphia, St Louis, Sydney, 2013; p. 280.Search in Google Scholar
34. European Council of Optometry and Optics. Position Paper – Contact Lenses are Safe: Don’t Misuse Them; Guidance on contact lens safety for wearers and professionals, 2020. https://www.ecoo.info/wp-content/uploads/2020/06/ECOO-Position-Paper-Contact-Lens-safety.pdf (accessed Jul 20, 2022).Search in Google Scholar
35. Koguchi, R., Jankova, K., Tanaka, M. Fluorine-containing bio-inert polymers: roles of intermediate water. Acta Biomater. 2022, 138, 34–56; https://doi.org/10.1016/j.actbio.2021.10.027.Search in Google Scholar PubMed
36. Trager, R. Efforts Underway in Europe to Ban PFAS Compounds; Chemistry World, 2021. https://www.chemistryworld.com/news/efforts-underway-in-europe-to-ban-pfas-compounds/4014038.article (accessed Jul 20, 2022).Search in Google Scholar
37. Buck, R. C., Franklin, J., Berger, U., Conder, J. M., Cousins, I. T., de Voogt, P., Jensen, A. A., Kannan, K., Mabury, S. A., van Leeuwen, S. P. J. Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classification, and origins. Integrated Environ. Assess. Manag. 2011, 7, 513–541; https://doi.org/10.1002/ieam.258.Search in Google Scholar PubMed PubMed Central
38. Organisation for Economic Co-operation and Development, (OECD). Reconciling Terminology of the Universe of Per‐ and Polyfluoroalkyl Substances: Recommendations and Practical Guidance; OECD Series on Risk Management, No. 61; OECD Publishing: Paris, 2021. https://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=ENV/CBC/MONO(2021)25&docLanguage=En (accessed Jul 20, 2022).Search in Google Scholar
39. Glüge, J., Scheringer, M., Cousins, I. T., DeWitt, J. C., Goldenman, G., Herzke, D., Lohmann, R., Ng, C. A., Trier, X., Wang, Z. An overview of the uses of per- and polyfluoroalkyl substances (PFAS). Environmental Science: Processes & Impacts 2020, 22, 2345–2373; https://doi.org/10.1039/d0em00291g.Search in Google Scholar PubMed PubMed Central
40. Cousins, I. T., Goldenman, G., Herzke, D., Lohmann, R., Miller, M., Ng, C. A., Patton, S., Scheringer, M., Trier, X., Vierke, L., Wang, Z., DeWitt, J. C. The concept of essential use for determining when uses of PFASs can be phased out. Environmental Science: Processes and Impacts 2019, 21, 1803–1815; https://doi.org/10.1039/c9em00163h.Search in Google Scholar PubMed PubMed Central
41. Glüge, J., London, R., Cousins, I. T., DeWitt, J., Goldenman, G., Herzke, D., Lohmann, R., Miller, M., Ng, C. A., Patton, S., Trier, X., Wang, Z., Scheringer, M. Information requirements under the essential-use concept: PFAS case studies. Environ. Sci. Technol. 2022, 56, 6232–6242; https://doi.org/10.1021/acs.est.1c03732.Search in Google Scholar PubMed PubMed Central
42. Ankley, G. T., Cureton, P., Hoke, R. A., Houde, M., Kumar, A., Kurias, J., Lanno, R., McCarthy, C., Newsted, J., Salice, C. J., Sample, B. E., Sepúlveda, M. S., Steevens, J., Valsecchi, S. Assessing the ecological risks of per- and polyfluoroalkyl substances: current state-of-the science and a proposed path forward. Environ. Toxicol. Chem. 2021, 40, 564–605; https://doi.org/10.1002/etc.4869.Search in Google Scholar PubMed PubMed Central
43. Royal Society of Chemistry. Risk-Based Regulation for Per- and Poly-Fluoroalkyl Substances (PFAS); Policy position, December 2021. https://www.rsc.org/globalassets/22-new-perspectives/sustainability/a-chemicals-strategy-for-a-sustainable-chemicals-revolution/pfas-policy-position-dec-2021.pdf (accessed Jul 20, 2022).Search in Google Scholar
44. Mulkiewicz, E., Jastorff, B., Składanowski, A. C., Kleszczyński, K., Stepnowski, P. Evaluation of the acute toxicity of perfluorinated carboxylic acids using eukaryotic cell lines, bacteria and enzymatic assays. Environ. Toxicol. Pharmacol. 2007, 23, 279–285; https://doi.org/10.1016/j.etap.2006.11.002.Search in Google Scholar PubMed
45. Bijland, S., Rensen, P. C. N., Pieterman, E. J., Maas, A. C. E., van der Hoorn, J. W., van Erk, M. J., Havekes, L. M., van Dijk, K. W., Chang, S.-C., Ehresman, D. J., Butenhoff, J. L., Princen, H. M. G. Perfluoroalkyl sulfonates cause alkyl chain length-dependent hepatic steatosis and hypolipidemia mainly by impairing lipoprotein production in APOE*3-Leiden CETP mice. Toxicol. Sci. 2011, 123, 290–303; https://doi.org/10.1093/toxsci/kfr142.Search in Google Scholar PubMed
46. Fenton, S. E., Ducatman, A., Boobis, A., DeWitt, J. C., Lau, C., Ng, C., Smith, J. S., Roberts, S. M. Per‐ and polyfluoroalkyl substance toxicity and human health review: current state of knowledge and strategies for informing future research. Environ. Toxicol. Chem. 2021, 40, 606–630; https://doi.org/10.1002/etc.4890.Search in Google Scholar PubMed PubMed Central
47. Solomon, K., Velders, G., Wilson, S., Madronich, S., Longstreth, J., Aucamp, P., Bornman, J. Sources, fates, toxicity, and risks of trifluoroacetic acid and its salts: relevance to substances regulated under the Montreal and Kyoto protocols. J. Toxicol. Environ. Health, Part B 2016, 19, 289–304; https://doi.org/10.1080/10937404.2016.1175981.Search in Google Scholar PubMed
48. Emmen, H. H., Hoogendijk, E. M., Klöpping-Ketelaars, W. A., Muijser, H., Duistermaat, E., Ravensberg, J. C., Alexander, D. C., Borkhataria, D., Rusch, G. M., Schmit, B. Human safety and pharmacokinetics of the CFC alternative propellants HFC 134a (1,1,1,2-tetrafluoroethane) and HFC 227 (1,1,1,2,3,3, 3-heptafluoropropane) following whole-body exposure. Regul. Toxicol. Pharmacol. 2000, 32, 22–35; https://doi.org/10.1006/rtph.2000.1402.Search in Google Scholar PubMed
49. European FluoroCarbons Technical Committee (EFCTC). HFCs, HFOs & HCFOs – Toxicology and Safety; Online report. https://www.fluorocarbons.org/toxicology-and-safety/ (accessed Jul 20, 2022).Search in Google Scholar
50. Shah, P., Westwell, A. D. The role of fluorine in medicinal chemistry. J. Enzyme Inhib. Med. Chem. 2007, 22, 527–540; https://doi.org/10.1080/14756360701425014.Search in Google Scholar PubMed
51. Hammel, E., Webster, T. F., Gurney, R., Heiger-Bernays, W. Implications of PFAS definitions using fluorinated pharmaceuticals. iScience 2022, 25, 104020; https://doi.org/10.1016/j.isci.2022.104020.Search in Google Scholar PubMed PubMed Central
52. European Federation of Pharmaceutical Industries and Associations (EFPIA) and Animal Health, Europe. Use and Risk of “Per- and Polyfluorinated Alkyl Substances” (PFAS) in Europe; Position paper, January 2022. https://www.efpia.eu/media/636866/pfas-position-_-efpia-and-animalhealtheurope-january-2022.pdf (accessed Jul 20, 2022).Search in Google Scholar
53. European FluoroCarbons Technical Committee (EFCTC). Metered Dose Inhalers. Online report. https://www.fluorocarbons.org/applications/metered-dose-inhalers/ (accessed Jul 20, 2022).Search in Google Scholar
54. Holden, B., Stretton, S., Lazon de la Jara, P., Ehrmann, K., LaHood, D. The future of contact lenses: Dk really matters. Contact Lens Spectrum. https://www.clspectrum.com/supplements/2006/february-2006/protecting-your-patient-s-eye-health/the-future-of-contact-lenses-dk-really-matters (accessed Jul 20, 2022).Search in Google Scholar
55. Dillehay, S. M. Does the level of available oxygen impact comfort in contact lens wear?: a review of the literature. Eye Contact Lens Sci. Clin. Pract. 2007, 33, 148–155; https://doi.org/10.1097/01.icl.0000245572.66698.b1.Search in Google Scholar PubMed
56. Bourcier, T., Thomas, F., Borderie, V., Chaumeil, C., Laroche, L. Bacterial keratitis: predisposing factors, clinical and microbiological review of 300 cases. Br. J. Ophthalmol. 2003, 87, 834–838; https://doi.org/10.1136/bjo.87.7.834.Search in Google Scholar PubMed PubMed Central
57. Nilsson, S. E. G. Bacterial keratitis and inflammatory corneal reactions: possible relations to contact lens oxygen transmissibility: the Harold A. Stein Lectureship 2001. CLAO J. 2002, 28, 62–65.Search in Google Scholar
58. Zaidi, T., Mowrey-McKee, M., Pier, G. B. Hypoxia increases corneal cell expression of CFTR leading to increased Pseudomonas aeruginosa binding, internalization, and initiation of inflammation. Investig. Ophthalmol. Vis. Sci. 2004, 45, 4066–4074; https://doi.org/10.1167/iovs.04-0627.Search in Google Scholar PubMed PubMed Central
59. Cheng, H. C., Liang, J. B., Lin, W. P., Wu, R. Effectiveness and safety of overnight orthokeratology with Boston XO2 high-permeability lens material: a 24 week follow-up study. Contact Lens Anterior Eye 2015, 39, 67–71; https://doi.org/10.1016/j.clae.2015.07.002.Search in Google Scholar PubMed
60. Lum, E., Swarbrick, H. A. Lens Dk/t influences the clinical response in overnight orthokeratology. Optom. Vis. Sci. 2011, 88, 469–475; https://doi.org/10.1097/opx.0b013e31820bb0db.Search in Google Scholar
61. Butrus, S. I., Klotz, S. A. Contact lens surface deposits increase the adhesion of Pseudomonas aeruginosa. Curr. Eye Res. 1990, 9, 717–724; https://doi.org/10.3109/02713689008999566.Search in Google Scholar PubMed
62. Bullimore, M. A., Mirsayafov, D. S., Khurai, A. R., Kononov, L. B., Asatrian, S. P., Shmakov, A. N., Richdale, K., Gorev, V. V. Pediatric microbial keratitis with overnight orthokeratology in Russia. Eye Contact Lens 2021, 47, 420–425; https://doi.org/10.1097/icl.0000000000000801.Search in Google Scholar
63. Huang, H. H., Chen, Y. Y., Wu, R., Lin, W. P. Effectiveness and safety of overnight orthokeratology with roflufocon E high-permeability lens material: a 36 weeks follow-up study. Biomedical Journal of Scientific & Technical Research 2020, 32, 24736–24741; https://doi.org/10.26717/BJSTR.2020.32.005204.Search in Google Scholar
64. Haque, S., Fonn, D., Simpson, T., Jones, L. Corneal refractive therapy with different lens materials, part 1: corneal, stromal, and epithelial thickness changes. Optom. Vis. Sci. 2007, 84, 343–348; https://doi.org/10.1097/opx.0b013e318042af1d.Search in Google Scholar PubMed
65. Eiden, S. B. The balance of properties – what’s important for ortho-K lens materials? Contact Lens Spectrum. https://www.clspectrum.com/newsletters/orthokeratology-in-practice/the-balance-of-properties-whats-important-for-o (accessed Jul 20, 2022).Search in Google Scholar
66. Guo, B., Cho, P., Efron, N. Microcystic corneal oedema associated with over-wear of decentred orthokeratology lenses during COVID-19 lockdown. Clin. Exp. Optom. 2021, 104, 736–740; https://doi.org/10.1080/08164622.2021.1896944.Search in Google Scholar PubMed
67. Swarbrick, H. A., Jayakumar, J., Co, W., He, D., Siu, C., Yau, B. Overnight corneal edema can modulate the short–term clinical response to orthokeratology lens wear. Investig. Ophthalmol. Vis. Sci. 2005, 46, 2056.Search in Google Scholar
68. Musgrave, C. S. A., Fang, F. Lens materials: a materials science perspective. Materials 2019, 12, 261; https://doi.org/10.3390/ma12020261.Search in Google Scholar PubMed PubMed Central
69. Chatterjee, S., Upadhyay, P., Mishra, M., Srividya, M., Akshara, M. R., Kamali, N., Zaidi, Z. S., Iqbal, S. F., Misra, S. K. Advances in chemistry and composition of soft materials for drug releasing contact lenses. RSC Adv. 2020, 10, 36751–36777; https://doi.org/10.1039/D0RA06681H.Search in Google Scholar
70. Nilsson, H., Kärrman, A., Rotander, A., Bavel, B., Lindström, G., Westberg, H. Biotransformation of fluorotelomer compound to perfluorocarboxylates in humans. Environ. Int. 2013, 51, 8–12; https://doi.org/10.1016/j.envint.2012.09.001.Search in Google Scholar PubMed
71. Ellis, D. A., Martin, J. W., De Silva, A. O., Mabury, S. A., Hurley, M. D., Sulbaek Andersen, M. P., Wallington, T. J. Degradation of fluorotelomer alcohols: a likely atmospheric source of perfluorinated carboxylic acids. Environ. Sci. Technol. 2004, 38, 3316–3321; https://doi.org/10.1021/es049860w.Search in Google Scholar PubMed
72. Kjølholt, J., Jensen, A. A., Warming, M. Short-chain polyfluoroalkyl substances (PFAS); Environmental project No. 1707, Published by the Danish Environmental Protection Agency, 2015. https://www2.mst.dk/Udgiv/publications/2015/05/978-87-93352-15-5.pdf (accessed Jul 20, 2022).Search in Google Scholar
73. ECHA. Trifluoroacetic Acid – Toxicological Summary; Registration Dossier, ECHA website. https://echa.europa.eu/registration-dossier/-/registered-dossier/5203/7/1# (accessed Jul 20, 2022).Search in Google Scholar
74. ECHA. Trifluoroacetic Acid – PBT Assessment; Registration Dossier, ECHA website. https://echa.europa.eu/registration-dossier/-/registered-dossier/5203/2/3# (accessed Jul 20, 2022).Search in Google Scholar
© 2023 Walter de Gruyter GmbH, Berlin/Boston
