Repeatability and Reproducibility of Retention Data and Band Profiles on RPLC Columns. II - Results Obtained with Symmetry C₁₈ Columns

The long-term repeatability, the column-to-column and the lot-to-lot reproducibilities of the retention and profile of the peaks obtained with 15 different Symmetry C18 columns were investigated. This packing material is an octadecyl bonded silica for RP-LC. Data characterizing the retention, the steric selectivity, the hydrogen bonding capacity, the hydrophobic interaction selectivity, the column efficiency, and the peak asymmetry are reported for a group of 30 neutral, acidic and basic compounds selected as probes. These data were acquired under five different sets of chromatographic conditions, using an HP 1100 liquid chromatograph and following an experimental protocol previously described. Statistical comparison of five different columns of one batch and of columns representative of 10 different batches are based on the high precision data obtained. For example, for 28 of the 30 components, the R.S.D.s of the retention factors measured on 10 columns from as many different batches were better than 2%. The R.S.D.s of the separation factors for 27 of these 30 components were below 1.4%. Such a level of column reproducibility is most impressive.