Comparative evaluation of pre-column derivatization strategies for PFAS analysis in paper-based food contact material using GC-MS

The analysis of paper-based food contact materials (FCM) has gained increasing attention due to the widespread use of per- and polyfluoroalkyl substances (PFAS) and their known toxic effects and environmental persistence. As regulatory frameworks for PFAS in FCM remain limited, sensitive and reliable analytical methods are necessary to ensure food safety. While PFAS analysis is predominantly performed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), a systematic development of gas chromatography coupled to mass spectrometry (GC-MS)-based methods for multiple PFAS classes remains limited. In this study, two pre-column derivatization techniques were optimized and evaluated for GC-MS determination of perfluoroalkyl carboxylic acids (PFCA), fluorotelomer alcohols (FTOH), and fluorotelomer carboxylic acids (FTCA). Both derivatization methods enabled qualification and quantification of the targeted PFAS with comparable limits of detection in the low ng/mL range. N,N-Dimethylformamide dimethyl acetal (DMFDMA) derivatization proved to be more sensitive with a limit of detection down to 0.85 ng/mL. In addition, this derivatization approach was successfully automated within the GC-MS workflow, resulting in sample preparation times comparable to those of LC-MS-based methods. The application of this optimized method to paper-based FCM demonstrated its suitability for real world FCM analysis. Results of PFAS content per targeted PFAS of 26.6 to 261.4 ng/g highlight the potential of GC-MS analysis, particularly when combined with automated derivatization, as a viable alternative or complement to LC-MS for PFAS analysis in FCM.