Determination of Copolymer Block-Length Distributions Using Fragmentation Data Obtained from Tandem Mass Spectrometry.

The block-length distribution (BLD) of polyamide and polyurethane copolymers was determined from mass spectrometry (MS) data. While nuclear magnetic resonance (NMR) traditionally determines the number-average block length, this work demonstrates that MS/MS is a viable option for the characterization of the distribution. An algorithm was implemented and modified to accurately determine copolymer BLDs from fragmentation data. The algorithm incorporates preferences in bond fragmentation. Evaluation of the algorithm encompassed the use of polyamide and polyurethane model systems. In both scenarios, the algorithm successfully derived BLDs, that corresponded well with the average block lengths obtained with 13C NMR. The newly developed algorithm enabled the characterization of BLDs based on MS/MS data. Typical trends in BLDs corresponding to distinct synthesis methods were discernible. These BLDs offer uniquely detailed insights into copolymer chemistry, potentially elucidating variations in functional properties of copolymers despite overall identical compositions.