Selectivity differences for C-18 and C-8 reversed-phase columns as a function of temperature and gradient steepness II. Minimizing column reproducibility problems

The choice of T and t(G) as variables for controlling selectivity and resol ution during reversed-phase liquid chromatography (RPLC) method development can be used to minimize problems caused by column batch-to-batch irreprodu cibility. When a new column fails to provide adequate separation of the sam ple, altered values of T and t(G) can be predicted that will restore the se paration obtained with the previous column. Alternatively, columns from dif ferent manufacturers can be tested during method development, in order to f ind a common set of conditions (T and t(G)) that provide acceptable separat ion with two or more of these columns. In this way, any of several columns from different sources become usable for the method. Examples are shown of these different computer-assisted procedures for minimizing problems due to column variability. (C) 2000 Elsevier Science B.V. All rights reserved.