title: Carbon-13 labeling for quantitative analysis of molecular movement in heterogeneous organic materials using secondary ion mass spectrometry.
abstract: Secondary ion mass spectrometry (SIMS) is used to probe the movement of macromolecules in heterogeneous organic systems. Using 13C tracer labeling and two model systems, polystyrene/poly(2-vinylpyridine) (PS/P2VP) and polystyrene/poly(4-bromostyrene) (PS/P4BrS), the diffusion of 13C-labeled PS has been investigated near the respective heterogeneous interfaces using a CAMECA-IMS-6F magnetic sector mass spectrometer. 13C labeling has been shown to greatly minimize matrix effects (i.e., changes in secondary ion yields due to changing chemical environment) in heterogeneous systems. P2VP is a nitrogen-rich polymer (C7H7N monomer composition), making it an excellent model polymer for exploration of this technique for potential future use in biological applications, and probing the PS/P4BrS interface demonstrates the versatility of this technique for analysis of various heteroatom-containing materials. Results confirm that the 13C-labeling method does indeed allow for quantitative analysis of molecular movement in heterogeneous organic systems containing matrix-enhancing heteroatoms such as nitrogen. Therefore, extension of this method to more complicated biological systems involving multiple heteroatoms (oxygen, nitrogen, etc.), layers, and heterogeneous interfaces, as well as two- and three-dimensional profiling and imaging using SIMS, can be envisaged.
authors.affiliation: Department of Materials Science & Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA. sh2536@columbia.edu
authors.forename: Shane E
authors.initials: SE
authors.lastname: Harton
authors.forename: Zhengmao
authors.initials: Z
authors.lastname: Zhu
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Stevie
authors.forename: Yoko
authors.initials: Y
authors.lastname: Aoyama
authors.forename: Harald
authors.initials: H
authors.lastname: Ade