Combining JMS-S3000 "SpiralTOF™-plus3.0" and size exclusion chromatography to analyze the end groups of high dispersity synthetic polymers and visualizing changes in the end groups
Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) can detect singly charged ions over a wide mass range, making it a powerful tool for structural analysis of polymers, such as confirmation of molecular weight distribution and estimation of end group compositions. However, in the analysis of polymers with high polydispersity, "mass discrimination" is an issue, in which the ion intensity in the high molecular weight range decreases due to various factors. On the other hand, size exclusion chromatography (SEC) can separate polymers by molecular weight, but it is challenging to identify end groups. Therefore, it is known that fractionating polymers with high polydispersity according to their molecular weight distribution by SEC, reducing the polydispersity, and then characterizing each fraction by MALDI-TOFMS are effective. In this report, we performed an end-group analysis of polymer samples with a high polydispersity and molecular weight of less than 50,000 by combining SEC and high-performance MALDI-TOFMS. In particular, we report on (i) improvement of the efficiency of fractionation by SEC and pretreatment for MALDI-TOFMS measurement, (ii) improvement of visualization of end group changes in mass spectra of SEC fractionated samples with reduced polydispersity, (iii) End group analysis in the high molecular weight region (molecular weight 10,000 to 20,000).