Continuous stationary phase columns consist of woven textile matrixes of fibers rolled into a cylindrical configuration and inserted into a liquid chromatography column. This configuration allows separations to be carried out at interstitial mobile phase velocities in excess of 100 cm/min and pressures of up to 700 psig for stationary phases based on cellulose. Ordinarily, these conditions would cause compaction of a cellulosic stationary phase to the point where flow is no longer possible. The packing of the column with cellulose as a continuous stationary phase enables these linear velocities to be achieved. Most importantly, this type of column allows the study of momentum transport and mass transfer in a media in which the mobile phase explores almost all of the void volumes in the column. The analysis of flow patterns in these columns has been modeled using elution patterns of both retained and unretained components, and plate height has been correlated as a function of velocities in the range of 1-100 cm/min. Engineering analysis of this type of chromatography column based on visual representation of the packed fibers by scanning electron microscopy, analysis of porosities using unretained (nonadsorbing) molecular probes, and application of momentum and mass transport equations is discussed.

A DEAE-cellulose stationary phase in a rolled configuration was used to separate recombinant secretory leukocyte protease inhibitor (rSLPI) from denaturants and reducing agents (3 M guanidine-HCl and 5 mM DTT) in less than 5 min to promote refolding of the protein to an active form. The mobile phase consisted of buffer and 500 mM NaCl, where NaCl suppressed binding of protein to this stationary phase. Separation of an initial concentration of 2 mg/mL protein from the other constituents resulted in 96% recovery of the rSLPI at an average concentration of 1.28 mg/mL. When incubated for 4 h at 20 degrees C, the fractionated rSLPI gave a 46% yield of properly refolded protein. The protein concentration was 6.4 times higher than that reported in a previously published method, where refolding was carried out by diluting the mixture of protein, denaturants, and reducing agents by a factor of 10. The results show that a combination of rapid chromatographic separation over a cellulosic stationary phase followed by protein refolding will significantly enhance process throughput by minimizing tankage, water requirements, and process time.

A woven textile fabric, consisting of 60% cotton/40% polyester, tightly rolled in a cylindrical configuration, has a three-dimensional structure with sufficient hydrodynamic stability to withstand interstitial eluent velocities of up to 300 cm/min when packed into standard liquid chromatography column assemblies. Demonstration of the pressure stability of the cotton/polyester fabric was followed up with experiments in which the cotton (cellulose) portion was derivatized and the fabric evaluated for chromatography of proteins. When derivatized to give a (diethylamino)ethyl (DEAE) anion exchanger, a velocity independent plate height of 2 mm, a static capacity of 115 mg of bovine serum albumin/g of stationary phase, and a dynamic protein loading capacity which decreases only 25% over an 800% increase in mobile-phase velocity from 6.7 to 54 cm/min was achieved. The fibers that make up the stationary phase have a relatively nonporous structure which minimizes pore diffusional effects. A protein separation of Cytochrome C from β-lactoglobulin A is shown to be completed by ion-exchange chromatography in less than 10 min using an NaCl step gradient. Gradient chromatography of a hen egg white shows resolution of the proteins into two major components (lysozyme and ovalbumin) as well as two minor ones. A size exclusion separation of PEG 20 000 from glucose requires only 90 s. These characteristics, together with the ability of the cellulose-based stationary phase to withstand rapid flow rates, indicate that this type of stationary phase has potential for applications where chromatography using DEAE-cellulose particles has proven successful.

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The objective of this paper is to introduce an American Society for Engineering Education (ASEE) Student Chapter, highlighting the purpose of developing a student chapter and the activities one can provide. The Purdue University Student Chapter, formed in the spring of 1993 as the first student ASEE chapter, has a threefold mission in providing relevant information to graduate students, undergraduate students, and underrepresented groups. The principal goal is to encourage mentorship among undergraduate students, graduate students, and faculty. To accomplish this goal, the student chapter provides seminars and workshops to educate graduate students about the various aspects of an academic career. Similarly, a seminar series on graduate study in engineering has been developed to educate undergraduates about graduate school. The Purdue University Student Chapter of ASEE currently has a membership base of more than 60 graduate students. The initial success of the Purdue Chapter has helped encourage formation of six student chapters at other universities.