The agreement between FTIR and EELS data now demonstrates the potential of STEM-vibEELS for mapping site-specific nonnative functional groups in biomolecules that can be introduced to selectively label proteins in a minimally invasive ('zero-size') manner using diverse methods to generate functional yet precisely observable systems in an essentially artefact-free manner . In particular, this technique therefore offers future promise for advancing our understanding of biomolecular structure and dynamics using chemically edited labels on a timescale and at a (nanometer) resolution in contextual biology in ways that are not yet tractable by other zero-size methods. We note that whilst here we have focused on utilization of Tfm as a zero-size analogue of Met, such repurposing of a common radical in biologythe methyl group (from -CH3→-CF3)can be envisaged not only in other protein residues but also in other diverse biomolecule classes. These include, for example, repurposing of lipidic methyl end groups (to measure chain terminus positioning higher order assemblies) or of 6-deoxy or acetamido glycans (to probe the dynamics and organization of vital glycoconjugates and polysaccharidic interfaces).