title: Numerical determination of non-Langmuirian adsorption isotherms of ibuprofen enantiomers on Chiralcel OD column using ultraviolet-circular dichroism dual detector.
abstract: Competitive adsorption isotherm of ibuprofen enantiomers on Chiralcel OD stationary phase at 298K was determined by the application of inverse method. Transport dispersive (TD) chromatography model was used to describe mass balances of the enatiomers. Axial dispersion and mass transfer coefficients were estimated from a series of linear pulse experiments. It was found that the overloaded elution profile of total concentration of racemic ibuprofen cannot be satisfactorily fitted by substituting bi-Langmuir model, the most widely used isotherm model for enantiomers, into TD model and tuning the isotherm parameters. UV-CD dual detector setup was then applied to obtain the individual overloaded elution profiles of both enantiomers. The more informative experimental data revealed non-Langmuirian adsorption behavior of ibuprofen enantiomers on chiralcel OD stationary phase. Two analytical binary isotherm models, both accounting for adsorbate-adsorbate interactions and having the feature of inflection points, were then evaluated. A comparison between quadratic model and Moreau model showed that the former gives better fitting results. The six parameters involved in quadratic model were determined stepwisely. Three of them were first obtained by fitting overloaded elution profiles of S-ibuprofen. The other three were then acquired by fitting overloaded elution profiles of both enantiomers recorded by UV-CD dual detector for racemic ibuprofen. A further attempt was also made at reducing the number of quadratic model parameters.
authors: Department of Chemical Engineering, Wenzhou University, Wenzhou 325035, Zhejiang, China.
authors: Hui
authors: H
authors: Li
authors: Department of Chemical Engineering, Wenzhou University, Wenzhou 325035, Zhejiang, China.
authors: Xiaoxiao
authors: X
authors: Jiang
authors: Daicel Chiral Technologies (China) Co., Ltd., No. 69 Xiya Road, Waigaoqiao Free Trade Zone, Shanghai 200131, China.
authors: Wei
authors: W
authors: Xu
authors: Department of Chemical Engineering, Wenzhou University, Wenzhou 325035, Zhejiang, China.
authors: Yongtao
authors: Y
authors: Chen
authors: Department of Chemical Engineering, Wenzhou University, Wenzhou 325035, Zhejiang, China. Electronic address: ywf@wzu.edu.cn.
authors: Weifang
authors: W
authors: Yu
authors: Department of Chemical Engineering, Wenzhou University, Wenzhou 325035, Zhejiang, China. Electronic address: xujin@wzu.edu.cn.
authors: Jin
authors: J
authors: Xu
mesh_terms: D000327:Adsorption; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation* / Q000379:methods*; D002845:Chromatography; D002942:Circular Dichroism; D007052:Ibuprofen / Q000032:analysis* / Q000737:chemistry; D008956:Models, Chemical; D048448:Phenylcarbamates / Q000737:chemistry*; D013237:Stereoisomerism; D014466:Ultraviolet Rays
chemical_list: D048448:Phenylcarbamates; C065943:cellulose tris-3,5-dimethylphenyl-carbamate; D002482:Cellulose; D007052:Ibuprofen
keywords: Chiralcel OD; Competitive adsorption equilibrium; Ibuprofen enantiomers; Inverse method; UV–CD dual detector