| Abstract
| - The chromatographic behavior of a series of racemicbenzodiazepines was evaluated under linear and nonlinearconditions on a new hybrid polymeric (DACH-ACR) chiralstationary phase (CSP). Differently substituted benzodiazepines were employed as probes to make hypothesesconcerning possible molecular interaction mechanismsoriginating between target compounds and active sites onthe CSP. Hydrogen bonds were found to be pivotal forchromatographic retention and chiral selectivity. Thecompetitive effect from a mobile-phase (MP) modifier ableto interact with the CSP through H-bonds was investigated. The performance of the polymeric DACH-ACR CSPfor preparative purposes was also evaluated. The competitive adsorption isotherms of two benzodiazepines,lorazepam and temazepam, were measured at differentMP compositions through the so-called inverse method.The adsorption data were fitted with a competitive bi-Langmuir adsorption isotherm. Enantiomeric separationsunder nonlinear conditions were modeled by using theequilibrium dispersive (ED) model of chromatography.Theoretical overloaded band profiles (obtained by solvingthe system of partial differential equations described bythe ED model) matched, in a significantly accurate way,the profiles experimentally measured.
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