Richard A. Henry, PhD
Consultant, The Pennsylvania State University, Department of Chemistry, University Park, PA 16802

"HPLC Columns- Reflection and Future Direction"

Bio:

Dr. Dr. Richard A. Henry received his B.S. degree in Chemistry from Juniata College in 1963 and Ph.D. in Analytical Chemistry from The Pennsylvania State University in 1966.  After a postdoctoral year in separations at Purdue University with Professor L. B. Rogers, he joined DuPont at the Experimental Station in Wilmington, DE and became one of the first employees of the Analytical Instrument Products Division. Dick worked closely with Dr. Jack Kirkland and others in the development of HPLC columns and packing materials. He joined the Penn State University chemistry faculty in 1985 as Director of Analytical Laboratories where he taught Instrumental Analysis to chemistry majors. In 1985, he also founded Keystone Scientific, Inc. where he developed and marketed HPLC columns and related separation technology. He retired from both Penn State University and Keystone Scientific in 2002, and remains active in teaching short courses on separation technology and as a consultant.  Dick has research interests in separation mechanisms and all applications of new LC column technology. He is also interested in hyphenated analytical techniques, especially the rapidly growing field of LC-MS, and all multidimensional separation methods. He served two terms as Chairman of the ACS Subdivision on Separations (1998-2002) and has also served for many years on its Executive Committee.

Email address: rhenry@psualum.com

Abstract:

High performance LC (HPLC) columns are filled with an insoluble substrate that either acts directly as a stationary phase or indirectly as a coated support for the stationary phase. The latter has become much more common. Column developments have often occurred in significant steps as new discoveries have been made to improve performance. These innovations have become established in practice after they have been proven by users and shown to be amenable to reproducible, economical mass production by suppliers. Small porous particles have become the most common column substrates, but superficially porous particles and monoliths have also been employed with considerable success. Highlights of developments leading to modern HPLC substrates and stationary phases will be reviewed.

The availability of ultra-high performance LC (UHPLC) columns containing sub-3µm particles has recently triggered changes in HPLC instrument designs to enable narrower peak widths and higher column operating pressures. These upgraded designs are often referred to as UHPLC instruments. In this presentation, origins of analyte dispersion (band-width) will be examined, including expected dispersion within the column bed and additional dispersion caused by various instrument volume elements within the sample flow path (extra-column dispersion). Contributions to total band-width from some less obvious variables (such as sample solvent, sample volume, column temperature, detector response, and data collection rate) will be discussed. Techniques for quantitatively measuring HPLC instrument band-width (IBW) will be described with the objective of matching instruments to columns for optimum performance.

In light of promising results with these new "ultra" columns and instruments, some possibilities for the future direction of HPLC column technology will be explored.