CHARACTERIZATION OF A RANGE OF ALKYL-BONDED SILICA HPLC STATIONARY PHASES - CORRELATION OF QUANTITATIVE SURFACE-ANALYSIS DATA WITH THE RETENTION BEHAVIOR OF NEUTRAL, ACIDIC, AND BASIC SOLUTES

investigation was made of the correlation between quantitative surface analytical data obtained by XPS and static SIMS and the chromatograph ic performance of a range of n-alkyl-bonded silica (C1-C18) packing ma terials, A series of acidic, basic, and neutral solutes was used to st udy the retention behavior, For comparison, analysis of bulk total per centage carbon (%C) and alkyl surface density of the bonded silica par ticulates were also included, Significant correlations were observed, in the majority of cases, between the retention factor (k) and the XPS C:Si atomic ratio, which was similar to that obtained between k and t he bulk %C or k and the bonded alkyl chain length, Similar significant correlations were also obtained between k and the static SIMS alkyl:S i ion peak area ratios, XPS alkyl:Si atomic ratios were calculated as an estimate of alkyl surface coverage of the silica support, and these correlated well with the surface density calculated from the bulk %C and the surface area of the packing material, The XPS alkyl:Si ratio a lso demonstrated a significant correlation with the peak asymmetry fac tor derived for basic solutes, These studies confirm that both ?IFS an d static SIMS can generate surface chemical data from chromatography p articulates, which has direct relevance to the prediction of chromatog raphic behavior, We believe that these techniques will prove to be eff ective tools to assist in the characterization of chromatographic supp orts and stationary phases.