A Study of Inhomogeneity Effects on Packed High Performance Liquid Chromatography Columns

The packing quality of a High Performance Liquid Chromatography column has significant impact on the resulting separations. In practice, problems in a packing occur through normal usage of a column. Resulting chromatograms from inhomogeneities exhibit varying problems such as extreme tailing and double peaks. Early detection of such problems is critical to fixing problems before their effect harms efficiency, but a fully developed theory of how inhomogeneities affect separations does not exist. The purpose of this work was to experimentally characterize HPLC column inhomogeneities and to begin preliminary simulations of HPLC columns with the computer simulation package STAR-CD. To do this, columns were first packed with a standard packing recommended by the manufacturer of the column. Later, two types of inhomogeneity were individually packed into columns: cavities and balls. The resulting chromatograms were analyzed and compared. The results show that as was expected, introducing inhomogeneities reduced separation quality. A simulation was created to model a one- dimensional column and a chromatogram was produced from this simulated column. From the simulated column, one can see that producing chromatograms entirely from a simulation produces an accurate, adjustable, and quick method for studying the column. Recommended further research includes more experiments involving inhomogeneities and simulations incorporating inhomogeneities. A further outlook includes research into pattern recognition with the goal of being able to analyze a series of chromatograms produced by the same column and notice small changes that indicate a specific inhomogeneity is forming