Practical Aspects of High Performance Column Selection in LC: Superficially Porous (SPP) or Sub-two Micron (STM)

Porous particle sizes have decreased to sub-two micron (STM). Separations formerly done on 5 micron particles can now be accomplished on much shorter STM columns in a fraction of the time with equal or better resolution.

For more complex separations, longer columns can generate high plate counts but at much higher pressure. Recently, an alternative particle design, the superficially porous particle (SPP), has developed. The particle concept has been around for over 40 years but the current version consists of a small solid core (e.g., 1.7-µm in diameter) surrounded by a thin porous shell (e.g., 0.5-µm thick) making a 2.7-µm particle diameter.

The efficiency of these SPPs is similar to the STM because of:

• Consistent spherical shape

• Rapid solute mass transfer

• Narrow particle size distribution

The larger particle size results in a much lower pressure drop when compared to STM particles, making them compatible with older 400 bar instruments as well as UHPLC systems.

This seminar will look at both types of particles and discuss when you might choose one over the other. Examples of pertinent applications will be cited.

Presenter: Rita Steed (Application Engineer, Agilent Technologies, Inc.)

Rita Steed began supporting the LC column line for Agilent in 1999. As a Chromatography Specialist (first with Chromatography, Inc., then directly for Agilent), Rita worked on-site with researchers in Pharmaceutical and other industries presenting technical seminars and assisting researchers with troubleshooting and method development. Rita has over 20 years of Chromatography experience in the Biotechnology, Chemical, and Pharmaceutical industries. She has held positions in Research, Sales, and Technical Service. Rita has earned degrees in Microbiology and Life Sciences/Biochemistry. In her current position, she is an inside Application Engineer supporting LC columns.