HPLC Separation guide March ’06 – standard C18 column in high throughput LC-MS applications - applications note

Introduction
In today’s paradigm of drug discovery, high throughput screening of hit-to-lead compounds is commonplace. Researchers screen millions of chemical compounds found in commercially available and proprietary libraries in search of a lead molecule, which reacts in a pre-defined biochemical process, and thus possesses the potential to become a FDA approved drug. Production of these huge chemical libraries begins in the arena of synthetic chemistry and exploits the techniques of combinatorial chemistry. The creation of these libraries solely for the intention of drug discovery places a large burden on the analytical chemist. Each library must be screened to provide the medicinal researcher insight into the identity and purity of each component. The job of the analytical chemist is therefore to design a method that will enhance the likelihood of accurate results and facilitate the throughput needed to support the synthetic processes.

As described previouslyi the variables that affect the length of the chromatographic run-time are (in order of increasing effect): column temperature, organic gradient steepness, instrument delay (dwell) volume, flow rate, and column length. Of these variables, the prudent choice of column composition, particle size, diameter and length is paramount. Shorter columns with smaller particles dramatically decrease analytical run time and can often maintain or increase resolution when compared to longer columns with larger particles.