Monolithic LC columns

摘要

Since the introduction of HPLC more than 30 years ago, columnpacking materials have changed dramatically--from irregularshaped to spherical, and from large particles to small. However, over the past decade, the performance of HPLC columns packed with small-sized particles has been prettymuch optimized. Recently, monolithic columns consisting of one piece of an organic polymer or silica with flow-through pores have been reported in the literature. These materials provide better stability and, more important, higher performance than conventional columns packed with particles. Although they can be prepared by various methods, monolithic columns prepared by the direct polymerization of monomers can be used in various analytical separations by HPLC and capillary electrochromatography (CEC). This article will show the structural and chromatographic features of these monolithic columns. Equations 1-5 define the properties of packing materials and columns (1-3), including the efficiency and flow resistance. (A glossary with a list of terms is avaliable on p 423 A). The three key terms in the right-hand side of Equation 2 are called the A-, B-, and C-terms, and are related to C_e and C_m, C_d, and C_(sm), respectively.