Development of a Parallel-Tandem Column Interface in a Two-Dimensional Liquid Chromatography System

An ion exchange-reversed-phase two-dimensional liquid chromatography (2D-LC) system was developed based on a newly designed interface. The interface was constructed by alternately connecting tandem columns to one of the parallel separation columns to increase the separation efficiency. Separation on the tandem column does not affect the switching frequency; the valve switching could be maintained at high frequency. The constructed interface could be used in both ambient and elevated temperature modes. Under high-temperature mode, only the tandem column was heated, which simplified the operation, decreased the backpressure, improved the solvent compatibility, and speeded up the separation. Tryptic digestion of four proteins was used to evaluate the performance of the developed system. The peak capacity of the 2D-LC system reached 650 under ambient conditions and 890 under high temperature conditions. When compared with the traditional parallel column interface constructed in this paper, the new interface produced a 60% higher peak capacity.