Abstract State-of-the-art liquid interaction chromatography (IC) allows separation of macromolecules according to chemical composition (CC), functionality or molecular topology in contrast to size-based approaches such as size exclusion chromatography (SEC), which has its limitations in distinguishing chemical structures. Yet, for macromolecules with multivariate molecular distributions, online identification and characterization of distinct components in bulk samples is a considerable challenge. A useful approach to narrow down the complexity of a given sample is preparative molar mass fractionation (pMMF) that provides fractions in mg or g scale, which can be subjected to further advanced analysis to elucidate the physical and structural properties of the sample. In this study, novel chain-walking polyethylenes (CWPE), which differ substantially in macromolecular architecture, are fractionated using pMMF. Using IC in temperature and solvent gradient modes (TGIC, SGIC), the pMMF fractions are separated according to branching topology. Quadruple-detector high temperature SEC is carried out to determine the physical properties and study the MM-dependent structural transformation of CWPE. A detailed branching analysis was carried out by means of nuclear magnetic resonance. Two-dimensional liquid chromatography (LC) hyphenating IC and SEC provides comprehensive bivariate correlations between MM and molecular topology.

中文翻译：

---

链步法聚乙烯的分馏和支化、构象和摩尔质量分布的阐明

摘要 最先进的液体相互作用色谱 (IC) 允许根据化学组成 (CC)、功能或分子拓扑结构分离大分子，这与基于尺寸的方法（如尺寸排阻色谱 (SEC)）相比有其局限性在区分化学结构方面。然而，对于具有多元分子分布的大分子，批量样品中不同成分的在线识别和表征是一个相当大的挑战。一种缩小给定样品复杂性的有用方法是制备摩尔质量分馏 (pMMF)，它提供 mg 或 g 级的馏分，可以对其进行进一步的高级分析，以阐明样品的物理和结构特性。在这项研究中，新型链行走聚乙烯（CWPE），它们在大分子结构上有很大差异，使用 pMMF 进行分级。在温度和溶剂梯度模式（TGIC、SGIC）下使用 IC，根据分支拓扑分离 pMMF 级分。进行四检测器高温 SEC 以确定物理性质并研究 CWPE 的 MM 依赖性结构转变。通过核磁共振进行详细的支化分析。二维液相色谱 (LC) 联用 IC 和 SEC 提供了 MM 和分子拓扑结构之间的全面双变量相关性。进行四检测器高温 SEC 以确定物理性质并研究 CWPE 的 MM 依赖性结构转变。通过核磁共振进行详细的支化分析。二维液相色谱 (LC) 联用 IC 和 SEC 提供 MM 和分子拓扑结构之间的全面双变量相关性。进行四检测器高温 SEC 以确定物理性质并研究 CWPE 的 MM 依赖性结构转变。通过核磁共振进行详细的支化分析。二维液相色谱 (LC) 联用 IC 和 SEC 提供了 MM 和分子拓扑结构之间的全面双变量相关性。