Simplified description of high-performance liquid chromatographic separation under overload conditions, based on the Craig distribution model

Simulation of elution profiles in liquid chromatography⿿I: Gradient elution conditions, and with mismatched injection and mobile phase solvents

“…These methods vary in terms of accuracy, speed and complexity. In this paper we present a general simulation program to predict the results of HPLC separations using a Craig-type simulation where the analyte propagates through a discretized space and time grid [7,10]. While this algorithm can be slow because of the necessity of calculating results at each point in time and space, it is relatively simple to understand and as we will show, produces results that agree well with closed form theory.…”

“…However, as mentioned by Czok and Guiochon [10], this can be addressed empirically by assuming that the extra peak broadening can be treated as a dispersion process where the extent of the dispersion is estimated using Fick's second law. (7) Or, in other words, the analyte at position m z,t is redistributed to the previous, current, and next positions to simulate kinetic broadening of the analyte zone:…”

“…The method development process in HPLC involves optimization of method parameters such as stationary phase, column dimensions, initial and final mobile phase compositions, as well as gradient time when gradient elution is used [1]. Computer simulation can aid in the optimization of separation methods, which can save time as compared to trial-and-error approaches [1][2][3][4][5][6][7][8][9]. In the past, several different methods for solving the mass transport equations defining the evolution of chromatographic peaks have been used including the Craig distribution model (based on the concept of theoretical plates) and mass balance equations (based on obtaining elution profiles through numerical integration) [10][11][12][13][14][15][16][17][18].…”

“…A number of reports in the literature have described methods for chromatographic simulations using a variety of numerical methods to solve the mass transport equations [7,[11][12][13]15,17,18,[25][26][27][28][29]. These methods vary in terms of accuracy, speed and complexity.…”

Separation behavior of basic compounds on unbonded silicon oxynitride and silica high-performance liquid chromatography stationary phases with reversed-phase eluents

“…Nevertheless, it has been recognized for a long time that the analysis of basic compounds poses particular difficulties in silica‐based reversed‐phase separations . The ionizable nature of basic compounds can lead to poor peak shapes when analyzed in RPLC, by detrimental interactions with silanol groups and overloading mechanisms . The existence of different types of adsorption sites and the mutual repulsion of ions held on the hydrophobic surface of the stationary phase were proposed to explain the cause of overload and peak tailing phenomenon in RPLC for separation of basic compounds.…”