Anal. Chem. 1993, 65, 2243-2248
2243
Macroporous Polymeric Stationary-Phase Rod as Continuous Separation Medium for Reversed-Phase Chromatography Q. Ching Wang, Frantisek Svec, and Jean M. J. Fr6chet* Department of Chemistry, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
A macroporous poly (styrene-cedivinylbenzene) rod has been prepared by a free-radical polymerization of a mixture containing monomers, initiator, and porogenic solvent in the confines of a chromatographic column and used for the first time in the very fast reversed-phase HPLC of proteins. Characterizationof the pore structure of the continuous rod by mercury intrusion porosimetry revealed a large volume of pores with a diameter of about 1 pm to pores below 100 nm. Size exclusion chromatographyand scanning electron microscopy confirmed the unusual pore size distribution. The presence of large pores make the rod easily permeable to eluents, and therefore,the back pressure of the rod column is modest even at high flow rates. The efficiency of the polymerized column is almost independent of the flow rate.The slope of the line showing capacity factor vs composition of the mobile phase was determined for several proteins, and a gradient for the separation of their mixtures was developed. Excellent separation was achieved even at a high flow rate of 25 mL/min as documented by the resolution data. Tripling the length of the column did not improve the column resolution in protein separation.
INTRODUCTION Despite many advantages, HPLC chromatographiccolumns packed with typical particulate sorbents also have some limitations. The slow diffusional mass transfer of solutes into the stagnant mobile phase present in the pores of the separation medium and the large void volume between the packed particles are the most important problems.192 The chromatographicliterature deals mainly with the first problem while the second, which also contributes to peak broadening, remains somewhat neglected. Introduction of very small porous particles (
