title: Optimization of the separation of chlorophenols with stepwise gradient elution in reversed phase liquid chromatography.
abstract: An optimization technique based on gradient elution was used to separate eleven chlorophenols by reversed phase liquid chromatography. The separation was based on gradient elution with a stepwise variation pattern of the volume fraction of organic modifier, phi, in the mobile phase. Initially, two-, three-, and four-parameter equations which describe the dependence of ln k' upon phi, were examined for their ability to fit the experimental data. It was found that, among these equations, the four-parameter equation gave the best fit of the experimental data. In addition to separation optimization, a non-linear least squares program with a grid search for initial estimates was used to determine the best variation pattern. The best variation pattern was obtained with phi(1)= 0.27, phi(2)= 0.39, phi(3)= 0.62, t(1) = 33 min, and t(2) = 11 min. This pattern allowed the chromatographic separation of the chlorophenols with a good resolution and a total analysis time of 51 min. Good agreement was observed between predicted and experimental values of the retention times under optimal condition.
authors.affiliation: Department of Chemistry, University of Mazandaran, Babolsar, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Hadjmohammadi
authors.forename: Kamyar
authors.initials: K
authors.lastname: Kamel
authors.forename: Mohammad Hosein
authors.initials: MH
authors.lastname: Fatemi
mesh_terms: D002733:Chlorophenols / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*
chemical_list: D002733:Chlorophenols