Exploring better column selectivity choices in ultra-high performance liquid chromatography using Quality by Design principles

An older method for amlodipine was reworked with the goal to reduce the analysis time of 60 min below 6 min. To select the best column for short and robust analysis, 9 different UHPLC column chemistries were investigated using 3-dimensional resolution spaces based on 12 experiments using modelling software. The main variables used were gradient time (tG), temperature (T) and the pH of eluent A. The best critical resolution was calculated and located in a 3-dimensional space in an automated fashion and the corresponding best experiments were carried out. The work (9 × 12 = 108 runs) was finished with an UHPLC instrument in less than 24 h. The comparison between predictions and real experiments showed an excellent correlation with differences typically less than 0.04 min (<3 s) in average, although the set points were located at quite different conditions on gradient times, pH's and temperatures for the individual columns. All columns could perform the required baseline separation at their individual best working points with satisfactory results.

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► We developed UHPLC methods by DryLab software on 9 different type stationary phases.
► The predicted retention times were in good agreement with the experimental ones.
► Computer modelling allows to find the best separation on a given column very fast.