Comprehensive profiling and quantification of antifogging additives based on fatty acid composition by GC-MS and its application in different matrices

As polymer additives, antifogging additives are used for, among other things, food packaging or in agricultural films. Here, they prevent the formation of water droplets on the inside of the film. Since they contain a hydrophilic structural moiety, they can be leached out of the polymer by interacting with water. Therefore, methods are required to study the fate of the (leached) additives. Since additives on the market comprise diverse structures, and also contain a range of compounds, a method was developed to determine the hydrophobic fatty acid moiety of antifogging additives which is based on gas chromatography coupled with mass spectrometry (GC-MS). Different extraction and derivatization protocols were tested to optimize the method and determine the best recoveries (between 106 and 117 %), resulting in rapid and low effort sample preparation. Limits of detection varied between 0.01 pg and 12.15 ng on column. The method presented can not only be used to detect the additive fatty acids, but is also suitable for detecting leached antifogging additives in matrices such as plant leaves and soil. In summary, three different commercially available antifogging additives were analyzed with the method. All showed a structural diversity beyond the fatty acids specified by the manufacturer. Using this fatty acid approach, it was observed that all three additives adhered to leaves when foliarly applied. It was also shown that significantly increased amounts of fatty acids were detectable even after washing the leaves with hexane or water, indicating a fatty acid residue on the treated leaves. However, a negligible effect of the adherent antifogging additives on plant physiological parameters as well as on selected metabolites was observed within the short experimental period.