A reversed-phase chromatographic stationary phase/pH/organic modifier screen is used as a first wave method development tool for pharmaceutical applications.In this scouting screen, each column is systematically exposed to multiple pHs and organic modifiers, and the best chromatographic condition is selected for further optimization.It was observed, however, that some columns were (reversibly or irreversibly) modified upon exposure to neutral to high pH conditions, producing inconsistent and irreproducible results for subsequent method development screens.This phenomenon has been termed "column memory effect".In order to gain fundamental understanding of this column memory effect phenomenon and to ensure quality of the screening results, we set out to study stationary phases where memory effect was observed to be significant.A column test protocol (PQRI) was used to probe the columns in an effort to understand what fundamental changes have occurred on the stationary phases during the course of the screen.Based on the findings, a regeneration procedure was incorporated into the screening system to ensure consistent intra-screening chromatographic results.