Synthesis of n-isomers: Native and deuterium-labelled short-chain perfluoroalkane sulfonamide derivatives

Abstract

Perfluorooctane sulfonamide derivatives have been extensively used by industry for their surfactant properties and as building blocks for other perfluoroalkyl substances (PFAS). Due to their environmental impact and their potential degradation to other harmful PFAS, short-chain sulfonamide derivatives alternatives were introduced. However, these are now also suspected to be present in different environmental matrices and there is a lack of labelled and unlabelled reference standards to perform analyses. To address this gap, 40 native and deuterium labelled short-chain perfluoroalkane sulfonamide derivatives were synthesized, utilizing commercial perfluoroalkane sulfonyl fluoride as starting materials. All products were synthesized and then purified to obtain linear n-isomer reference standards. NMR, GC-FID-MS and LC-MS techniques were used for product identification and purity assessment. Recrystallization method was developed to selectively isolate the n-isomer from the isomer mixtures, thereby providing valuable reference and internal standards for environmental and toxicological investigations.