There are many factors that influence the performance of a high performance liquid chromatography (HPLC) stationary phase, of which the chemical nature of the bonded phase ligand is important, but by no means all encompassing. Minor manufacturing parameters such as the method of electropolishing the internal surface of the column can also have an effect on the selectivity and efficiency produced by a particular column.
Several attempts have been made to produce a «definitive» set of chemical probes to best characterize the huge number of stationary phases available (well over 1000 different types are currently available). As yet a harmonized set of test probes and methodologies has not been identified, however three, independent, publicly available databases of HPLC columns exist today:
- ACD Labs Column Selection Database — based on the early work of Tanaka and developed by Euerby and Peterson, http://www.acdlabs.com/products/adh/chrom/chromproc/index.php#colsel
- United States Pharmacopoeia Convention (USP) database — based on test probes established using a National Institute of Standards and Technology (NIST) Standard Reference material, http://www.usp.org/USPNF/columnsDB.html
- The Impurities Working Group of the Product Quality Research Institute (PQRI) Drug Substance Technical Committee — uses probes based on the hydrophobic subtraction model of Dolan, Snyder, and Carr, http://www.usp.org/USPNF/columnsDB.html