Porous Layer open tubular (PLOT) columns

[adam]

I just came across PLOT columns while skimming through one of my old texts. I wonder why they are so rarely used. Aren't there some benefits to the higher surface area?

Thanks Adam

[Answer Man]

Plot columns have their place, which is the separation of small volatile molecules (such as methane, ethane, etc) to slightly larger molecules. These columns are typically used for compounds which will not separate using a volatiles column (such as a 502.2). Because Plot columns are capillary in size, they can be a substitute for packed columns when using a capillary column GC, requiring no hardware upgrade.

The downside to using a Plot column is that they may generate particles, which can damage detectors such as a mass spec. In addition, excessively long analysis times are needed for larger molecules.