Retention factors k have been measured for 67 neutral, acidic and basic solutes of highly diverse molecular structure (size, shape, polarity, hydrogen bonding, pKa, etc.) on 10 different C18 columns (other conditions constant). These data have been combined with k values from a previous study (86 solutes, five different C8 and C18 columns) to develop a six-term equation for the correlation of retention as a function of solute and column. Values of k can be correlated with an accuracy of ±1-2% (1 standard deviation). This suggests that all significant contributions to column selectivity have been identified (and can be measured) for individual alkyl-silica columns which do not have an embedded polar group. That is, columns of the latter kind can be quantitatively characterized in terms of selectivity for use in the separation of any sample.
Bibliographical noteFunding Information:
The present study (including following papers [1,2] ) was supported in part by a Small Business Innovation Research (SBIR) grant from the National Institutes of Health (US Department of Health and Human Services). For all three papers, we are much indebted for the considerable advice, support and critical comments of Drs. J.J. Kirkland (formerly at Agilent Technologies), U.D. Neue (Waters Corp.), S.C. Rutan (Virginia Commonwealth University), D.V. McCalley (University of the West of England), and M.R. Euerby (Astra Zeneca R&D, Loughborough, UK), as well as the companies who provided the columns used in the present study (see Experimental ).
Copyright 2008 Elsevier B.V., All rights reserved.
- Alkyl-silica columns
- Column selectivity
- Retention prediction
- Stationary phases, LC