Adsorption Chromatography on PLOT (Porous-Layer Open-Tubular) Columns: A New Look at the Future of Capillary GC

Abstract

The applicability of highly efficient porous-layer open-tubular (PLOT) columns is described. Capillary columns coated with aluminum oxide, silica, and the molecular sieve types 5Å and 13× are evaluated, and a number of applications are given. Because of their unique retention characteristics, these adsorption materials are suited for very specific and difficult separations. Aluminum oxide and silica are used for the analysis of low concentrations of C₁ to C₁₀ hydrocarbons; molecular sieve type 5Å has a unique retention for permanent gases; and molecular sieve type 13× gives a very specific separation of naphthenes from paraffins, which simplifies the identification of naphthas. The characteristics and uses of these PLOT columns now and in the future are discussed.