Analysis of active sites and heterogeneity in commercial reversed-phase octadecylsilanated silica with numerically calculated sorption distributions

Effect of the temperature on the isotherm parameters of phenol in reversed-phase liquid chromatography

“…The EM method allows the calculation of the adsorption energy distribution, hence the characterization of the surface heterogeneity [22][23][24][25][26][27][28]. The apparent, global, or overall adsorption isotherm is related to the local isotherm and to the distribution of adsorption constants by the following equation:…”

“…The expectation maximization algorithm was used to calculate the affinity energy distribution from the raw adsorption data, without requiring any prior assumption on the isotherm model [23][24][25][26][27][28]. The AED derived from the EM method were used to validate the isotherm model selected from the fitting process.…”

“…This work was supported in part by Grant CHE-02-44693 of the National Science Foundation and by the cooperative [25][26][27][28][29][30][31][32][33][34][35][36] agreement between the University of Tennessee and the Oak Ridge National Laboratory.…”

Potential of adsorption isotherm measurements for closer elucidating of binding in chiral liquid chromatographic phase systems

“…K min and K max are the minimum and the maximum equilibrium constant and are governed by 1/C max and 1/C min , respectively, where C min and C max are the lowest and highest mobile phase concentrations measured in the adsorption isotherm [36]. As local adsorption isotherm model usually the Langmuir or Jovanovic model is used, but also BET (Brunauer, Emmett, and Teller) has been used [37].…”

Determination of adsorption isotherms in supercritical fluid chromatography

“…The Scatchard plots (not shown) were made from the raw data; these were concave which indicates that the adsorption cannot be described with a Langmuir adsorption isotherm and one should use a heterogeneous model, like bi-Langmuir. Adsorption energy distributions were calculated from the ECP data (not shown), but because the column load in this study were too low the calculations did not converge and no conclusions can be drawn from these calculations [39,41]. The bi-Langmuir model was fitted to the data; see Eq.…”