Agilent Technologies R&D and Marketing GmbH & Co KG, Hewlett-Packard-Str. 8, Waldbronn, 76337, Germany.
Gustavus Adolphus College, 800 West College Avenue, St. Peter, MN 56082, United States.
J Chromatogr A. 2021 Feb 22;1639:461880. doi: 10.1016/j.chroma.2021.461880. Epub 2021 Jan 14.
The use of two-dimensional liquid chromatography (2D-LC) continues to grow as the advantages over 1D-LC become increasingly clear in specific application areas, and the number of experienced 2D-LC users increases. As with any technique, however, there is always room for innovation that could improve the performance of 2D-LC. In recent years the technical aspects and potential benefits of a volume-based mode of operation were studied in detail for 1D-LC. The salient features of this approach that are immediately interesting for use in 2D-LC are two-fold. First, the ability to maintain a nominally constant pressure in the second dimension by dynamically adjusting the flow rate to compensate for changes in the viscosity of the fluid in the D flow path provides a means to more fully utilize the pressure capability of the pumping system, and accelerates separations in the second dimension (D). Second, constant pressure operation minimizes physical stress on the system components and the D column. In this paper we discuss the aspects of volume-based operation of LC that are particularly relevant to 2D-LC systems. The proof-of-concept experiments illustrate the viability of the constant pressure mode of operation for the second dimension of 2D-LC. In the described separations the throughput improvement is on the order of 10%; this gain will be strongly application-dependent, and may be as large as several tens percent in some cases. Future work will involve a detailed investigation of the impact of the constant pressure mode on robustness of D separations.
二维液相色谱（2D-LC）的使用不断增加，因为在特定应用领域中，其相对于一维液相色谱（1D-LC）的优势越来越明显，并且具有 2D-LC 经验的用户数量也在增加。然而，与任何技术一样，总会有改进的空间，这可能会提高 2D-LC 的性能。近年来，人们详细研究了基于体积的操作模式在一维液相色谱中的技术方面和潜在优势。这种方法的显著特点是，可以通过动态调整流速来补偿 D 流路中流体粘度的变化，从而在第二维中保持名义上恒定的压力，这对二维液相色谱的应用具有重要意义。首先，这种方法可以更充分地利用泵送系统的压力能力，并加速第二维（D）的分离。其次，恒压操作可以最大限度地减少系统组件和 D 柱的物理应力。本文讨论了与二维液相色谱系统特别相关的基于体积的液相色谱操作的各个方面。概念验证实验说明了恒压模式在二维液相色谱第二维中的可行性。在描述的分离中，通量提高了约 10%；这种增益将强烈依赖于应用，在某些情况下可能高达百分之几十。未来的工作将涉及详细研究恒压模式对 D 分离稳健性的影响。
