Practical method for the definition of chromatographic peak parameters in preparative liquid chromatography

A practical method was established for the definition of chromatographic parameters in preparative liquid chromatography. The parameters contained both the peak broadening level under different amounts of sample loading and the concentration distribution of the target compound in the elution. The parameters of the peak broadening level were defined and expressed as a matrix, which consisted of sample loading, the forward broadening and the backward broadening levels. The concentration distribution of the target compound was described by the heat map of the elution profile. The most suitable stationary phase should exhibit the narrower peak broadening and it was best to broaden to both sides to compare to the peak under analytical conditions. Besides, the concentration distribution of the target compounds should be focused on the middle of the elution. The guiding principles were validated by purification of amitriptyline from the mixture of desipramine and amitriptyline. On the selected column, when the content of the impurity desipramine was lower than 0.1%, the recovery of target compound was much higher than the other columns even when the sample loading was as high as 8.03 mg/cm³ . The parameters and methods could be used for the evaluation and selection of stationary phases in preparative chromatography.