HPLC Column Technology: State-of-The-Art

Improvements in HPLC column technology continue. Since the last Special Supplement on columns in 2008 (1), the continued need for high-throughput separation, the encountering of more complex samples, the need to analyze very polar compounds more easily, and the increased availability of very high pressure instruments has placed additional demands on the HPLC column. In terms of high throughput, no less than 24 companies have responded and have developed small particle columns of 2 µm and under. In addition, the number of superficially porous particle (SPP) columns has expanded, and users are finding that the high-efficiency-at-low-pressure advantage brings them added advantages. With more complex samples, longer columns packed with sub-2-µm particles require higher pressures with pumps now available to 1300 bar. It will be of interest to see if the lower pressure, high-efficiency SPP columns and monoliths, the latter of which have seen advances in the research of polymeric monoliths for applications to small molecules, will be the direction that chromatographers go to keep column pressures reasonable. To solve complex separations, a great deal of interest has been created around comprehensive LC×LC, where the first dimension is carried out on a slower but orthogonal column to the second dimension. The development of more orthogonal columns to provide better resolution is underway and instrumentation that can conveniently perform such experiments is beginning to appear. The pressure race among leading instrumentation companies appears to be in full swing but column capability might still tax the extracolumn effects as columns continue to become more efficient with smaller volumes. Automated instruments for method development and walk-up LC–MS systems have come into their own to make method development easier.

Ronald E. Majors

Although reversed-phase chromatography is still king, the increasing use of hydrophilic interaction liquid chromatography (HILIC) for polar compounds only slightly or unretained on typical reversed-phase columns has been seen. More columns for chiral recognition have been introduced as some patents on more popular technologies have expired.

To update LCGC readers, I have assembled an excellent selection of HPLC column experts to bring us up-to-date in specific areas of column technology. First, I will discuss some of the innovations that have occurred and are occurring in reversed-phase chromatography. Frantisek Svec will update the tremendous progress being made in monolith technology, while Chris Pohl highlights columns for ion-exchange and ion chromatography focusing on small molecules. Next, Tom Beesley, an early worker in the field of chiral separations, will discuss chiral columns and some new chemistries. David Carr, who has worked in HPLC for nearly 40 years, will discuss biocolumns, an area where he has considerable experience. Finally, Matthias Pursch will discuss automated method development and show some examples of "real world" industrial applications. I do hope that you enjoy this Special Supplement and find something of interest and value. Good reading.

(1) "Recent Developments in LC Column Technology" LCGC North America S26 (S4), April 2008.

Ronald E. Majors

Recent Developments in

LC Column Technology Editor