ABSTRACT
Liquid chromatography (LC), in its broader sense, continues to be an indispensable technique in the analytical laboratory with a remarkable impact on chemical analysis. This is the result of numerous theoretical and technological advances, particularly in the area of high-performance liquid chromatography (HPLC). Column technology is one of the most investigated topics among separation scientists. Consequently, new products in HPLC columns are frequently introduced into the market. This is not surprising since it is within the column that the chromatographic processes take place, making the column the “heart” of the separation system. One aspect in the development of HPLC column technology has focused on new separation media to achieve more efficient and faster separations than those encountered in conventional LC. HPLC separations are typically performed using one of three column formats: open tubes, columns packed with small particles, and very recently, in monolithic
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columns. For the most part, open tubular columns are fused-silica capillaries in which the stationary phase is attached to the inner walls of the capillary. The fabrication of this column format is quite simple, and very efficient separations are achieved; however, the amount of stationary phase available to achieve separation is low because of the limited amount of surface area available, leading to low mass loadability. Further, open tubular columns are limited to separations in the analytical scale. Columns packed with small beads provide a significantly larger surface area than that found in the open tubular columns, and hence, a larger amount of stationary phase is available. Packed columns exist for analytical and preparative scale purposes. It is very well established that decreasing the particle diameter brings an increase in separation efficiency and resolution. The small packing materials(<2µm), however, come at the price of an increased column backpressure that is necessary to drive the mobile phase through the column, which in most cases, requires the use of ultrahigh pressure liquid chromatography (UHPLC) [1-6].
