Open tubular liquid chromatographic system for using columns with inner diameter of 2 µm. A tutorial

We have recently demonstrated the remarkable performances of liquid chromatography (LC) using 2-µm-i.d. open tubular (OT) columns; peak capacities of 2000+ within less than three hours have been routinely obtained at an elution pressure of around 100 bar or less. However, only a small number of researchers have been involved in the research in this area; part of the reason is due to the issues associated with setting up open tubular liquid chromatography (OTLC) systems. While cautions should be taken here and there in carrying out separations, but none of the issues can inhibit us from performing OTLC separations. Therefore, we feel it desirable to write a tutorial on how to build an OTLC system. In this tutorial, we introduce the key components for the apparatus, how to construct/prepare them or where to purchase them, and how to assemble them together into a complete system. We further discuss the advantages and disadvantages of the system; we mention particularly the practical issues from using the narrow (2-µm-i.d.) columns and how to mitigate these issues.