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Accurate and rapid estimation of adsorption isotherms in liquid chromatography using the inverse method on plateaus
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Surface Biotechnology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing.
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Surface Biotechnology. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Surface Biotechnology.
2005 (English)In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1099, 167-174 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2005. Vol. 1099, 167-174 p.
Keyword [en]
inverse method, numerical method, LC, competitive adsorption isotherms
National Category
Analytical Chemistry Computational Mathematics
Identifiers
URN: urn:nbn:se:uu:diva-95292DOI: 10.1016/j.chroma.2005.10.043OAI: oai:DiVA.org:uu-95292DiVA: diva2:169453
Available from: 2006-12-22 Created: 2006-12-22 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Adsorption Isotherm Parameter Estimation in Nonlinear Liquid Chromatography
Open this publication in new window or tab >>Adsorption Isotherm Parameter Estimation in Nonlinear Liquid Chromatography
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis concerns the development and validation of methods for the industrially important area of adsorption isotherm parameter estimation in preparative, nonlinear high performance liquid chromatography (HPLC). Preparative chromatography is a powerful separation method to get pure compounds from more or less complex liquid mixtures, e.g., mixtures of mirror-image molecules. Computer simulations can be used to optimize preparative chromatography, but then competitive adsorption isotherm parameters are usually required. Here two methods to estimate adsorption isotherm parameters are treated: (i) the perturbation peak (PP) method and (ii) the inverse method (IM).

A new theory for the PP method was derived and led to a new injection technique which was validated experimentally. This injection technique solved the severe problem with vanishing peaks and enabled us to use the PP method to estimate binary competitive adsorption isotherms valid over a broad concentration range. Also, the injection technique made it possible to estimate competitive adsorption isotherms for a quaternary mixture for the first time. Finally, an interesting perturbation peak phenomenon, known as the “Helfferich Paradox”, was experimentally verified for the first time.

The IM is a relatively new method to determine adsorption isotherm parameters. It has the advantage of requiring very small samples, but also requires an advanced computer algorithm. An improved implementation of this computer algorithm was developed and tested experimentally. Also, a variant of the IM called “the inverse method on plateaus” was tested experimentally and the estimated adsorption isotherm parameters were shown to be valid over a broader concentration range than those estimated with the standard IM.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2005. 24 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 96
Keyword
High performance liquid chromatography (HPLC), Preparative chromatography, Competitive adsorption isotherm parameters, Perturbation peak (PP) method, Inverse method (IM), Computer simulation, Parameter estimation, Numerical method
National Category
Computational Mathematics Analytical Chemistry
Research subject
Scientific Computing
Identifiers
urn:nbn:se:uu:diva-5971 (URN)91-554-6355-X (ISBN)
Public defence
2005-10-19, Room B21, Uppsala Biomedical Centre, Husargatan 3, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2005-09-27 Created: 2005-09-27 Last updated: 2011-10-27Bibliographically approved
2. Development and Validation of Methods for Characterization of Multi-Component Systems in Preparative LC
Open this publication in new window or tab >>Development and Validation of Methods for Characterization of Multi-Component Systems in Preparative LC
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Utveckling och Validering av Metoder för Karaktärisering av Flerkomponentsystem vid Preparativ Vätskekromatografi
Abstract [en]

This thesis concerns the development and validation of methods for characterization of multi-component preparative LC systems. Measurements of competitive adsorption isotherms are performed to gain detailed information about the interactions inside the chromatography column. This information increases our understanding of the separation process and makes it possible to perform computer simulations and numerical optimizations to find optimal operating conditions.

The methods under focus are called “the tracer-pulse method”, “the inverse method”, and “the inverse method on plateaus”. They are extensions of existing methods, with new experimental and numerical procedures to enable rapid and accurate multi-component adsorption isotherm determination. In the validation it was shown that they can produce results agreeing with traditional methods and that the acquired adsorption isotherm parameters can be used in simulations to accurately predict the outcome of preparative LC separations.

The methods were used to characterize several complex LC systems and two phenomena were discovered and theoretically treated: 1) The presence of invisible deformed peaks in single-component systems. 2) Peak deformations encountered with modern chiral stationary phases, caused by strongly adsorbed eluent additives. The latter type of deformation was highly tuneable and it was possible to adjust the enantiomer peak shapes so that the peaks tailed in opposite directions with the sharp sides in between, yielding baseline resolution at remarkably high sample loads.

In a final applied study both the LC-based perturbation peak method and a biosensor method based on surface plasmon resonance (SPR) were used for the first time for detailed characterization of chiral drug-protein interactions. The fundamental properties of the two very different methods were compared and it was found that the LC method is more suitable for multi-component analysis and that the SPR method is more suitable for stronger interactions.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 48 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 256
Keyword
Analytical chemistry, Liquid chromatography, Preparative LC, Chiral LC, Multi-component LC, Adsorption isotherm, Tracer-pulse method, Inverse method, Inverse method on plateaus, Peak deformations, Chiral drug-protein interactions, Analytisk kemi
Identifiers
urn:nbn:se:uu:diva-7422 (URN)91-554-6762-8 (ISBN)
Public defence
2007-01-19, B22, Biomedicinskt centrum, Husargatan 3, Uppsala, 13:15
Opponent
Supervisors
Available from: 2006-12-22 Created: 2006-12-22Bibliographically approved

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Arnell, RobertFornstedt, Torgny

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