Interfacing liquid chromatography (LC) with electrospray ionization (ESI) to enable on-line MS detection had been initially implemented using reversed phase LC, which in the past three decades remained the default type of chromatography used for LC/MS and LC/MS/MS studies of protein structure. In contrast, the advantages of other types of LC as front-ends for ESI MS, particularly those that allow biopolymer higher order structure to be preserved throughout the separation process, enjoyed relatively little appreciation until recently. However, the past few years witnessed a dramatic surge of interest in the so-called "native" (with "non-denaturing" being perhaps a more appropriate adjective) LC/MS and LC/MS/MS analyses within the bioanalytical and biophysical communities. This review focuses on recent advances in this field, with an emphasis on size exclusion and ion exchange chromatography as front-end platforms for protein characterization by LC/MS. Also discussed are the benefits provided by the integration of chemical reactions in the native LC/MS analyses, including both ion chemistry in the gas phase (e.g., limited charge reduction for characterization of highly heterogeneous biopolymers) and solution-phase reactions (using the recently introduced technique cross-path reactive chromatography).

中文翻译：

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全蛋白质水平的 LC/MS：使用天然 LC/MS、交叉路径反应色谱 (XP-RC) MS 研究生物分子结构和相互作用

将液相色谱 (LC) 与电喷雾电离 (ESI) 连接起来以实现在线 MS 检测最初是使用反相 LC 实现的，在过去的三十年中，反相 LC 仍然是用于 LC/MS 和 LC/MS/的默认色谱类型蛋白质结构的 MS 研究。相比之下，其他类型的液相色谱作为 ESI MS 前端的优势，尤其是那些允许在整个分离过程中保留生物聚合物高阶结构的优势，直到最近才受到相对较少的重视。然而，过去几年见证了生物分析和生物物理界对所谓的“原生”（“非变性”可能是更合适的形容词）LC/MS 和 LC/MS/MS 分析的兴趣急剧增加. 本综述重点关注该领域的最新进展，重点是体积排阻和离子交换色谱作为 LC/MS 蛋白质表征的前端平台。还讨论了在天然 LC/MS 分析中集成化学反应所带来的好处，包括气相中的离子化学（例如，用于表征高度异质生物聚合物的有限电荷减少）和溶液相反应（使用最近的引入技术交叉路径反应色谱）。