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Sibanda N, Pfukwa H, Bungu PE, Pasch H. Advanced tools for molecular characterization of bio-based and biodegradable polymers. Anal Bioanal Chem 2024:10.1007/s00216-024-05255-3. [PMID: 38517490 DOI: 10.1007/s00216-024-05255-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 03/08/2024] [Accepted: 03/12/2024] [Indexed: 03/24/2024]
Abstract
Bio-based and biodegradable materials play a vital role in a sustainable and green economy. These materials must exhibit properties that are similar to or better than the properties of oil- or coal-based materials and require sophisticated synthesis technologies and detailed knowledge of structure-property correlations. For comprehensive molecular structure elucidation, advanced analytical methods, including coupled and hyphenated techniques that combine advanced fractionation and information-rich spectroscopic detectors, are an indispensable tool. One important tool for fractionating complex polymers regarding molecular size is size exclusion chromatography. For fractionating polymers with regard to chemical composition, solvent (or temperature) gradient HPLC has been developed. The combination of different liquid chromatography methods in comprehensive two-dimensional HPLC setups is another important tool. Today, a toolbox of HPLC methods is in place that enables the fractionation of complex bio-based and biodegradable polymers according to the most important molecular parameters including molecular size, composition, functionality, and branching. Here, an overview of the different techniques and some major applications is presented. Some representative developments in the field are discussed, and different techniques, experimental protocols, and applications are highlighted.
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Affiliation(s)
- Ndumiso Sibanda
- Department of Chemistry and Polymer Science, University of Stellenbosch, Stellenbosch, 7602, South Africa
| | - Helen Pfukwa
- Department of Chemistry and Polymer Science, University of Stellenbosch, Stellenbosch, 7602, South Africa
| | - Paul Eselem Bungu
- Department of Correlative Characterization, Institute of Functional Materials for Sustainability, Helmholtz Center Hereon, Kantstrasse 55, 14513, Teltow, Germany
| | - Harald Pasch
- Department of Correlative Characterization, Institute of Functional Materials for Sustainability, Helmholtz Center Hereon, Kantstrasse 55, 14513, Teltow, Germany.
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Eselem Bungu PS, Luetzow K, Lettau O, Schulz M, Neffe AT, Pasch H. Stereochemical Heterogeneity Analysis of Polylactides by Multidimensional Liquid Chromatography. Anal Chem 2024; 96:4716-4725. [PMID: 38465448 PMCID: PMC10955512 DOI: 10.1021/acs.analchem.4c00336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/23/2024] [Accepted: 02/27/2024] [Indexed: 03/12/2024]
Abstract
A new and robust high-performance liquid chromatography (HPLC) method that separates poly(lactic acid) (PLA) according to its stereochemical composition is presented. Using this method, poly(l-lactide) incorporating trace amounts of meso-lactide resulting from the racemization is separated from the pristine polymer. To prove this aspect in more detail, a representative poly(l-lactic acid) standard, assumed to be highly homogeneous, was separated using this method. The result showed that this was not the case as a fraction incorporating meso-lactide due to racemization occurring during the synthesis is separated. Employing two-dimensional liquid chromatography (2D-LC), the molar mass differences of the separated species were investigated, and fractions with similar molecular sizes were detected, confirming that the LC separation is solely based on stereochemical heterogeneity. The sample was further fractionated by preparative HPLC, followed by an in-depth analysis of the fractions using homonuclear decoupling in proton nuclear magnetic resonance (1H NMR). Convincing results that unveiled significant differences in the stereochemistry of the isolated PLA fractions were obtained. Subsequent analysis by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) also confirmed oligomer series with different end group structures, indicating that the applied HPLC method is very sensitive to minor variations in stereochemistry and end groups. This integrated approach offers detailed insight into the structural characteristics of PLA polymers, contributing to a better understanding of their composition and potential applications.
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Affiliation(s)
- Paul S. Eselem Bungu
- Department
of Multidimensional Polymer Characterization, Institute of Active Polymers, Helmholtz-Center Hereon, Kantstrasse 55, Teltow 14513, Germany
| | - Karola Luetzow
- Department
of Multidimensional Polymer Characterization, Institute of Active Polymers, Helmholtz-Center Hereon, Kantstrasse 55, Teltow 14513, Germany
| | - Olaf Lettau
- Department
of Multidimensional Polymer Characterization, Institute of Active Polymers, Helmholtz-Center Hereon, Kantstrasse 55, Teltow 14513, Germany
| | - Matthias Schulz
- PSS
Polymer Standards Service GmbH (Now Part of Agilent Technology), In der Dalheimer Wiese 5, Mainz 55120, Germany
| | - Axel T. Neffe
- Department
of Multidimensional Polymer Characterization, Institute of Active Polymers, Helmholtz-Center Hereon, Kantstrasse 55, Teltow 14513, Germany
| | - Harald Pasch
- Department
of Multidimensional Polymer Characterization, Institute of Active Polymers, Helmholtz-Center Hereon, Kantstrasse 55, Teltow 14513, Germany
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Pasch H, Ndiripo A, Bungu PSE. Multidimensional analytical protocols for the fractionation and analysis of complex polyolefins. Journal of Polymer Science 2022. [DOI: 10.1002/pol.20210236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Harald Pasch
- Department of Chemistry and Polymer Science University of Stellenbosch De Beers Street Stellenbosch 7602 South Africa
| | - Anthony Ndiripo
- Department of Chemistry and Polymer Science University of Stellenbosch De Beers Street Stellenbosch 7602 South Africa
- Polymer Separation Group Leibniz‐Institut für Polymerforschung Dresden e.V Hohe Strasse 6 Dresden 01069 Germany
- Department of Applied Chemistry National University of Science and Technology Box AC939, Ascot Bulawayo Zimbabwe
| | - Paul Severin Eselem Bungu
- Department of Chemistry and Polymer Science University of Stellenbosch De Beers Street Stellenbosch 7602 South Africa
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Kang Y, Zhao X, Han X, Ji X, Chen Q, Pasch H, Lederer A, Liu Y. Conformation and persistence length of chitosan in aqueous solutions of different ionic strengths via asymmetric flow field-flow fractionation. Carbohydr Polym 2021; 271:118402. [PMID: 34364548 DOI: 10.1016/j.carbpol.2021.118402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/01/2021] [Accepted: 07/01/2021] [Indexed: 12/24/2022]
Abstract
Conformation of chitosan in acidic aqueous solutions is strongly influenced by ionic strength, but the conventional employed size exclusion chromatography is limited to high ionic strength. Here we show that conformation of chitosan in acetate buffer down to millimolar ionic strength can be studied via asymmetric flow field-flow fractionation (AF4), where the separation is governed by the diffusion properties of the chitosan molecules and assisted by the electrostatic repulsion of the polyelectrolyte from the channel membrane. The size of chitosan decreases with ionic strength due to increasing screening of the polyelectrolyte effect. The persistence length of chitosan in the solutions, obtained by fitting the conformation plot by the wormlike chain model, decreases linearly with the Debye screening length from 44.5 nm at a salt concentration of 1.25 mM dominated by the electrostatic contribution to 8.6 nm in 800 mM acetate buffer close to its intrinsic persistence length of 7.7 nm.
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Affiliation(s)
- Yu Kang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China
| | - Xinyue Zhao
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China
| | - Xintong Han
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Xiangling Ji
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China
| | - Quan Chen
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China
| | - Harald Pasch
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa
| | - Albena Lederer
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa; Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany
| | - Yonggang Liu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
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Ndiripo A, Ndlovu PZ, Albrecht A, Pasch H. Improving temperature gradient interaction chromatography of polyolefins by simultaneous use of different stationary phases. J Chromatogr A 2021; 1653:462416. [PMID: 34332317 DOI: 10.1016/j.chroma.2021.462416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
Temperature gradient interaction chromatography (TGIC) at high temperatures is a powerful method for the chemical composition separation of polyolefins. TGIC is a two-step process where the sample is crystallized on the stationary phase at low temperature followed by the elution of the sample components using a temperature gradient towards high temperatures. For TGIC typically a porous graphitic carbon (PGC) stationary phase is used. The separation mechanism is based on crystallization and adsorption/desorption phenomena and it has been shown that co-crystallization and co-adsorption may affect the separation. The present study reports on the simultaneous use of a non-adsorptive and an adsorptive stationary phase (column) in series to utilize both crystallization and adsorption for improved separation in TGIC. A silica column is used as the non-adsorptive support to allow for the crystallization of the polyolefin sample in the absence of an adsorptive force followed by the typical PGC column for adsorption/desorption. Accordingly, the loci of crystallization and adsorption/desorption are well separated from each other and can be adjusted independently. This novel column setup allows the sample to be introduced slowly onto the second (adsorptive) column eliminating possible co-adsorption and poor selectivity. Low molar mass polyethylene comprising of oligomers with approximately C30C130 was used to illustrate the importance of a non-adsorptive column for improved separation. Utilizing a non-adsorptive silica column allows for higher dynamic flow rates during crystallization, which improves separation. Shorter adsorptive columns are found to be more efficient in this experimental protocol as compared to standard TGIC experiments. Smaller PGC column sizes result in reduced longitudinal and Eddy diffusion and, hence, higher resolution of low and high molar mass polyolefins.
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Affiliation(s)
- Anthony Ndiripo
- Department of Chemistry and Polymer Science, Stellenbosch University, PO Box X1, 7602 Stellenbosch, South Africa; Center Macromolecular Structure Analysis, Leibniz-Institut für Polymer Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany; Department of Applied Chemistry National University of Science and Technology, Box Ac. 939 Ascot, Bulawayo, Zimbabwe.
| | - Petronella Zabesuthu Ndlovu
- Department of Chemistry and Polymer Science, Stellenbosch University, PO Box X1, 7602 Stellenbosch, South Africa
| | - Andreas Albrecht
- Borealis Polyolefine GmbH, St. Peter-Strasse 25, Linz 4021, Austria
| | - Harald Pasch
- Department of Chemistry and Polymer Science, Stellenbosch University, PO Box X1, 7602 Stellenbosch, South Africa.
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Pasch H. Correction to: Thermal Field-Flow Fractionation as a Powerful Tool for the Fractionation of Complex Synthetic Polymers: A Perspective. Chromatographia 2021. [DOI: 10.1007/s10337-021-04055-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Viktor Z, Pasch H. Variable temperature asymmetric flow field-flow fractionation for the topology separation of poly(methyl methacrylate). Anal Chim Acta 2021; 1144:150-157. [DOI: 10.1016/j.aca.2020.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 11/27/2022]
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Zentel KM, Eselem Bungu PS, Degenkolb J, Pasch H, Busch M. Connecting the complex microstructure of LDPE to its rheology and processing properties via a combined fractionation and modelling approach. RSC Adv 2021; 11:33114-33123. [PMID: 35493580 PMCID: PMC9042246 DOI: 10.1039/d1ra03749h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/21/2021] [Indexed: 11/28/2022] Open
Abstract
Well-defined mini-plant low density polyethylene samples were fractionated preparatively according to their crystallizability via preparative temperature rising elution fractionation and according to molecular weight via preparative solvent gradient fractionation (pSGF). Rheology of the fractions was measured in both the small amplitude oscillatory shear (SAOS) and the non-linear extension regimes. The linear and non-linear rheology of the pTREF fractions were dominated by molecular weight effects, while the impact of the higher degree of long chain branching for the pSGF fractions with higher molecular weights was observed in van Gurp–Palmen plots and in strain hardening behavior in the extensional rheology measurements. Additionally, the experimental fractionation process was mimicked via modelling. The branching topologies of the bulk samples were obtained by coupled kinetic and Monte Carlo calculations. These topologies were fractionated computationally and the result were used to predict the rheological behavior of the individual fractions by applying the BoB algorithm with no parameter adjustment. The experimental observed trends were predicted by the model and the overall agreement was acceptable. This study demonstrates, that polymer fractionation is possible on a preparative scale and allows for the polymer flow properties characterization of the individual fractions, a method that is highly relevant during processing. Moreover, the fractionation process is followed and understood from the modelling point of view. The complex microstructure of LDPE regarding branching and molecular weight was correlated to its rheology and processing properties via preparative fractionation and modelling.![]()
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Affiliation(s)
- Kristina Maria Zentel
- Universität Hamburg, Institute for Technical and Macromolecular Chemistry, Bundesstr. 45, 20146 Hamburg, Germany
- Technical University of Darmstadt, Institute for Technical and Macromolecular Chemistry, Alarich-Weiß-Straße 8, 64287 Darmstadt, Germany
| | - Paul Severin Eselem Bungu
- University of Stellenbosch, Department of Chemistry and Polymer Science, PO Box X1, 7602 Matieland, South Africa
| | - Jonas Degenkolb
- Technical University of Darmstadt, Institute for Technical and Macromolecular Chemistry, Alarich-Weiß-Straße 8, 64287 Darmstadt, Germany
| | - Harald Pasch
- University of Stellenbosch, Department of Chemistry and Polymer Science, PO Box X1, 7602 Matieland, South Africa
| | - Markus Busch
- Technical University of Darmstadt, Institute for Technical and Macromolecular Chemistry, Alarich-Weiß-Straße 8, 64287 Darmstadt, Germany
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Zentel KM, Eselem Bungu PS, Pasch H, Busch M. Linking molecular structure to plant conditions: advanced analysis of a systematic set of mini-plant scale low density polyethylenes. Polym Chem 2021. [DOI: 10.1039/d1py00089f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two sample sets of low density polyethylene (LDPE) were investigated and differentiated via comprehensive analysis of their microstructures with specific emphasis on branching.
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Affiliation(s)
| | | | - Harald Pasch
- University of Stellenbosch
- Stellenbosch 7602
- South Africa
| | - Markus Busch
- Technical University of Darmstadt
- 64287 Darmstadt
- Germany
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Plüschke L, Ndiripo A, Mundil R, Merna J, Pasch H, Lederer A. Fractionation of chain walking polyethylene and elucidation of branching, conformation and molar mass distributions. International Journal of Polymer Analysis and Characterization 2020. [DOI: 10.1080/1023666x.2020.1840865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Laura Plüschke
- Leibniz-Institut für Polymerforschung Dresden e.V., Dresden, Germany
- Technische Universität Dresden, Dresden, Germany
| | - Anthony Ndiripo
- Department of Chemistry and Polymer Science, Stellenbosch University, Stellenbosch, South Africa
| | - Robert Mundil
- Department of Polymers, University of Chemistry and Technology, Prague, Czech Republic
| | - Jan Merna
- Department of Polymers, University of Chemistry and Technology, Prague, Czech Republic
| | - Harald Pasch
- Department of Chemistry and Polymer Science, Stellenbosch University, Stellenbosch, South Africa
| | - Albena Lederer
- Leibniz-Institut für Polymerforschung Dresden e.V., Dresden, Germany
- Technische Universität Dresden, Dresden, Germany
- Department of Chemistry and Polymer Science, Stellenbosch University, Stellenbosch, South Africa
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Affiliation(s)
- PaulSeverin Eselem Bungu
- Department of Chemistry and Polymer ScienceUniversity of Stellenbosch PO Box X1 Stellenbosch 7602 South Africa
| | - Kristina Pflug
- Institute for Technical and Macromolecular ChemistryUniversität Hamburg Bundesstr. 45 Hamburg 20146 Germany
| | - Harald Pasch
- Department of Chemistry and Polymer ScienceUniversity of Stellenbosch PO Box X1 Stellenbosch 7602 South Africa
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Ndiripo A, Albrecht A, Pasch H. Improving chromatographic separation of polyolefins on porous graphitic carbon stationary phases: effects of adsorption promoting solvent and column length. RSC Adv 2020; 10:17942-17950. [PMID: 35517227 PMCID: PMC9053593 DOI: 10.1039/d0ra00509f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/29/2020] [Indexed: 11/21/2022] Open
Abstract
The chromatographic separation of complex polyolefins on porous graphitic carbon stationary phases is strongly influenced by the composition of the mobile phase. Of particular interest is the effect of the chemical structure of the adsorption promoting solvent as this component of the mobile phase determines the adsorption–desorption behavior of the polyolefin molecules. In a systematic study, alkyl alcohols and linear alkanes are used as adsorption promoting solvents and the effect of the molecules' carbon chain length on chromatographic resolution is investigated. As representative examples, solvent gradient interaction chromatography experiments on polypropylene stereoisomers and ethylene-co-1-octene copolymers are presented. In a further study, the effect of increasing chromatographic column length on the solvent gradient separation of ethylene-co-1-octene copolymers is investigated. In summary, it is shown that the polypropylene stereoisomers are retained in 1-octanol as well as in n-decane and n-dodecane, allowing for identification of the individual stereoisomers in complex blends. For ethylene-co-1-octene copolymers it is shown that separation improves with increasing carbon chain length of the adsorption promoting solvent. Maximum resolution is obtained when a column length of 300 mm is used with 1-dodecanol as the adsorption promoting solvent. The chromatographic separation of complex polyolefins on porous graphitic carbon stationary phases is strongly influenced by the composition of the mobile phase.![]()
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Affiliation(s)
- Anthony Ndiripo
- Department of Chemistry and Polymer Science, Stellenbosch University Stellenbosch South Africa
| | - Andreas Albrecht
- Borealis Polyolefine GmbH St. Peter-Strasse 25 Linz 4021 Austria
| | - Harald Pasch
- Department of Chemistry and Polymer Science, Stellenbosch University Stellenbosch South Africa
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Ndiripo A, Pasch H. Retention of polypropylene stereoisomers in solvent gradient interaction chromatography on porous graphitic carbon as influenced by temperature and mobile phase composition. J Chromatogr A 2020; 1618:460865. [DOI: 10.1016/j.chroma.2020.460865] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/23/2019] [Accepted: 01/08/2020] [Indexed: 10/25/2022]
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Kang Y, Ji X, Bo S, Liu Y, Pasch H. Chromatographic mode transition from size exclusion to slalom chromatography as observed for chitosan. Carbohydr Polym 2020; 235:115950. [DOI: 10.1016/j.carbpol.2020.115950] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/19/2019] [Accepted: 02/03/2020] [Indexed: 11/24/2022]
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Affiliation(s)
- Anthony Ndiripo
- Department of Chemistry and Polymer Science, Stellenbosch University, P. O. Box X1,7602 Stellenbosch, South Africa
| | - Andreas Albrecht
- Borealis Polyolefine GmbH, St. Peter-Strasse 25, Linz 4021, Austria
| | - Harald Pasch
- Department of Chemistry and Polymer Science, Stellenbosch University, P. O. Box X1,7602 Stellenbosch, South Africa
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Viktor Z, Pasch H. Two-dimensional fractionation of complex polymers by comprehensive online-coupled thermal field-flow fractionation and size exclusion chromatography. Anal Chim Acta 2020; 1107:225-232. [DOI: 10.1016/j.aca.2020.02.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/08/2020] [Accepted: 02/15/2020] [Indexed: 10/25/2022]
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Murima D, Pasch H. Characterization of Complex Branched Polymers by Multidetector Thermal Field‐Flow Fractionation. Macromol Rapid Commun 2019; 41:e1900556. [DOI: 10.1002/marc.201900556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/28/2019] [Indexed: 01/20/2023]
Affiliation(s)
- Douglas Murima
- Department of Chemistry and Polymer ScienceUniversity of StellenboschStellenbosch Private Bag X1 7602 Matieland South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer ScienceUniversity of StellenboschStellenbosch Private Bag X1 7602 Matieland South Africa
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Sigwinta M, Ndiripo A, Wewers F, Pasch H. Deformulation of commercial linear low‐density polyethylene resins by advanced fractionation and analysis. POLYM INT 2019. [DOI: 10.1002/pi.5950] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Mawande Sigwinta
- Department of Chemistry and Polymer ScienceUniversity of Stellenbosch Stellenbosch South Africa
- Department of ChemistryCape Peninsula University of Technology Bellville South Africa
| | - Anthony Ndiripo
- Department of Chemistry and Polymer ScienceUniversity of Stellenbosch Stellenbosch South Africa
| | - Francois Wewers
- Department of ChemistryCape Peninsula University of Technology Bellville South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer ScienceUniversity of Stellenbosch Stellenbosch South Africa
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Venter P, Causon T, Pasch H, de Villiers A. Comprehensive analysis of chestnut tannins by reversed phase and hydrophilic interaction chromatography coupled to ion mobility and high resolution mass spectrometry. Anal Chim Acta 2019; 1088:150-167. [PMID: 31623711 DOI: 10.1016/j.aca.2019.08.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 06/29/2019] [Accepted: 08/16/2019] [Indexed: 12/16/2022]
Abstract
In this study, we report a methodology based on reversed phase LC (RP-LC) and hydrophilic interaction chromatography (HILIC) separations coupled to ion mobility (IM) and high resolution mass spectrometry (HR-MS) for the detailed analysis of hydrolysable tannins. The application of this approach to the analysis of an industrial chestnut (Castanea sativa, wood chips) tannin extract is demonstrated. A total of 38 molecular species, including a large number or isomers, were identified in this sample based on HR-MS(E) and UV absorption spectral information as well as retention behaviour in both separation modes. In total, 128 and 90 isomeric species were resolved by RP- and HILIC-LC-IM-TOF-MS, respectively. The combination of low- and high collision energy mass spectral data with complementary chromatographic separations allowed tentative and putative identification of twenty molecular species, comprising 78 isomers, in chestnut for the first time. Ion mobility resolved six new dimeric and trimeric vescalagin conformers with unique arrival (drift) times, including new conformers of roburin A-D which were not separated using either RP-LC or HILIC. HILIC was found to be the preferred separation mode for the analysis of vescalagin derivatives, while RP-LC is preferred for the analysis of ellagitannins with a cyclic glucose core. For the complete separation of the galloyl glucose species, comprehensive HILIC × RP-LC separation would be required.
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Affiliation(s)
- Pieter Venter
- Stellenbosch University, Department of Chemistry and Polymer Science, Private Bag X1, Matieland, 7602, South Africa
| | - Tim Causon
- University of Natural Resources and Life Sciences (BOKU), Department of Chemistry, Division of Analytical Chemistry, Vienna, Austria
| | - Harald Pasch
- Stellenbosch University, Department of Chemistry and Polymer Science, Private Bag X1, Matieland, 7602, South Africa
| | - André de Villiers
- Stellenbosch University, Department of Chemistry and Polymer Science, Private Bag X1, Matieland, 7602, South Africa.
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Venter P, Pasch H, de Villiers A. Comprehensive analysis of tara tannins by reversed-phase and hydrophilic interaction chromatography coupled to ion mobility and high-resolution mass spectrometry. Anal Bioanal Chem 2019; 411:6329-6341. [DOI: 10.1007/s00216-019-01931-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/15/2019] [Accepted: 05/17/2019] [Indexed: 11/29/2022]
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Murima D, Pasch H. Comprehensive branching analysis of star-shaped polystyrenes using a liquid chromatography–based approach. Anal Bioanal Chem 2019; 411:5063-5078. [DOI: 10.1007/s00216-019-01846-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/05/2019] [Accepted: 04/11/2019] [Indexed: 12/17/2022]
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22
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Affiliation(s)
- Upenyu L. Muza
- Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Stellenbosch, South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Stellenbosch, South Africa
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23
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Viktor Z, Farcet C, Moire C, Brothier F, Pfukwa H, Pasch H. Comprehensive two-dimensional liquid chromatography for the characterization of acrylate-modified hyaluronic acid. Anal Bioanal Chem 2019; 411:3321-3330. [DOI: 10.1007/s00216-019-01799-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/14/2019] [Accepted: 03/21/2019] [Indexed: 11/25/2022]
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24
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Radebe N, Beskers T, Greyling G, Pasch H. Online coupling of thermal field-flow fractionation and Fourier transform infrared spectroscopy as a powerful tool for polymer characterization. J Chromatogr A 2019; 1587:180-188. [DOI: 10.1016/j.chroma.2018.12.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/06/2018] [Accepted: 12/09/2018] [Indexed: 11/16/2022]
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25
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Eselem Bungu PS, Pasch H. Bivariate molecular structure distribution of randomly branched polyethylene by orthogonal preparative fractionation. Polym Chem 2019. [DOI: 10.1039/c9py00343f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Orthogonal preparative fractionations provide bivariate molecular structure distributions of randomly branched polyethylene.
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Affiliation(s)
- Paul S. Eselem Bungu
- University of Stellenbosch
- Department of Chemistry and Polymer Science
- Matieland 7602 Stellenbosch
- South Africa
| | - Harald Pasch
- University of Stellenbosch
- Department of Chemistry and Polymer Science
- Matieland 7602 Stellenbosch
- South Africa
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26
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Ndiripo A, Pornwilard MM, Pathaweeisariyakul T, Pasch H. Multidimensional chromatographic analysis of carboxylic acid-functionalized polyethylene. Polym Chem 2019. [DOI: 10.1039/c9py01191a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carboxy-functionalized polyethylene is comprehensively analysed using a multidimensional fractionation approach based on high-temperature HPLC, two-dimensional liquid chromatography and selective infrared detection.
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Affiliation(s)
- Anthony Ndiripo
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- South Africa
| | | | | | - Harald Pasch
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- South Africa
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27
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Muza UL, Greyling G, Pasch H. Stereocomplexation of Polymers in Micelle Nanoreactors As Studied by Multiple Detection Thermal Field-Flow Fractionation. Anal Chem 2018; 90:13987-13995. [DOI: 10.1021/acs.analchem.8b03590] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Upenyu L. Muza
- Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Matieland, South Africa
| | - Guilaume Greyling
- Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Matieland, South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science, University of Stellenbosch, 7602 Matieland, South Africa
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28
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Greyling G, Lederer A, Pasch H. Thermal Field-Flow Fractionation for the Investigation of the Thermoresponsive Nature of Star and Linear Polystyrene. MACROMOL CHEM PHYS 2018. [DOI: 10.1002/macp.201800417] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Guilaume Greyling
- Department of Chemistry and Polymer Science University of Stellenbosch; Private Bag X1; 7602 Matieland South Africa
| | - Albena Lederer
- Leibniz Institute of Polymer Research Dresden, Hohe Straße 6; D-01069 Dresden and Technische Universität Dresden; D-01062 Dresden Germany
| | - Harald Pasch
- Department of Chemistry and Polymer Science University of Stellenbosch; Private Bag X1; 7602 Matieland South Africa
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29
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Venter P, Muller M, Vestner J, Stander MA, Tredoux AGJ, Pasch H, de Villiers A. Comprehensive Three-Dimensional LC × LC × Ion Mobility Spectrometry Separation Combined with High-Resolution MS for the Analysis of Complex Samples. Anal Chem 2018; 90:11643-11650. [PMID: 30193064 DOI: 10.1021/acs.analchem.8b03234] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Comprehensive two-dimensional liquid chromatography (LC × LC) and ion mobility spectrometry-mass spectrometry (IMS-MS) are increasingly being used to address challenges associated with the analysis of highly complex samples. In this work, we evaluate the potential of the combination of these techniques in the form of a comprehensive three-dimensional LC × LC × IMS separation system. As application, hydrophilic interaction chromatography (HILIC) × reversed phase LC (RP-LC) × IMS-high-resolution MS (HR-MS) was used to analyze a range of phenolic compounds, including hydrolyzable and condensed tannins, flavonoids, and phenolic acids in several natural products. A protocol for the extraction and visualization of the four-dimensional data obtained using this approach was developed. We show that the combination of HILIC, RP-LC, and IMS offers excellent separation of complex phenolic samples in three dimensions. Benefits associated with the incorporation of IMS include improved MS sensitivity and mass-spectral data quality. IMS also provided separation of trimeric procyanidin isomeric species that could not be differentiated by HILIC × RP-LC or HR-MS. On the traveling wave IMS (TWIMS) system used here, both IMS separation performance and the extent of second dimension (2D) undersampling depend on the upper mass scan limit, which might present a limitation for the analysis of larger molecular ions. The performance of the LC × LC × IMS system was characterized in terms of practical peak capacity and separation power, using established theory and taking undersampling and orthogonality into account. An average increase in separation performance by a factor of 13 was found for the samples analyzed here when IMS was incorporated into the HILIC × RP-LC-MS workflow.
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Affiliation(s)
- Pieter Venter
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland 7602 , South Africa
| | - Magriet Muller
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland 7602 , South Africa
| | - Jochen Vestner
- Institute of Viticulture and Oenology , DLR Rheinpfalz , Neustadt an der Weinstraße 67435 , Germany
| | - Maria A Stander
- Department of Biochemistry , Stellenbosch University , Private Bag X1 , Matieland 7602 , South Africa
| | - Andreas G J Tredoux
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland 7602 , South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland 7602 , South Africa
| | - André de Villiers
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland 7602 , South Africa
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30
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Botha C, Kuntz JF, Moire C, Farcet C, Pfukwa H, Pasch H. Molar Mass Analysis of Hydrophobically Modified Hyaluronic Acid by SEC-MALLS: Facing the Challenges of Amphiphilic Biomacromolecules. MACROMOL CHEM PHYS 2018. [DOI: 10.1002/macp.201800233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Carlo Botha
- Department of Chemistry and Polymer Science; Stellenbosch University; Private Bag X1 Matieland 7602 South Africa
| | | | - Claudine Moire
- L’Oréal Research and Innovation; Aulnay-Sous-Bois 93600 France
| | - Céline Farcet
- L’Oréal Research and Innovation; Aulnay-Sous-Bois 93600 France
| | - Helen Pfukwa
- Department of Chemistry and Polymer Science; Stellenbosch University; Private Bag X1 Matieland 7602 South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science; Stellenbosch University; Private Bag X1 Matieland 7602 South Africa
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31
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Muza U, Greyling G, Pasch H. Core microstructure, morphology and chain arrangement of block copolymer self-assemblies as investigated by thermal field-flow fractionation. J Chromatogr A 2018; 1562:87-95. [DOI: 10.1016/j.chroma.2018.05.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 05/22/2018] [Accepted: 05/27/2018] [Indexed: 12/01/2022]
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32
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Ndiripo A, Pasch H. Comprehensive Analysis of Oxidized Waxes by Solvent and Thermal Gradient Interaction Chromatography and Two-Dimensional Liquid Chromatography. Anal Chem 2018; 90:7626-7634. [PMID: 29807432 DOI: 10.1021/acs.analchem.8b01480] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This report addresses the comprehensive analysis of oxidized/functionalized polyethylene waxes according to chemical composition and molar mass by selective chromatographic methods. For the first time, tailored high-temperature interaction chromatography in solvent gradient (HT-SGIC) and thermal gradient (HT-TGIC) modes are used for the chemical composition separation of these materials. Separation protocols are developed using three model wax samples with different degrees of oxidation. For the chromatographic separations polar silica gel is used as the stationary phase. Solvent gradients of decane and cyclohexanone are used in HT-SGIC at 110 °C to separate the bulk waxes into several heterogeneous fractions according to polarity and the type of functionality. Column temperature and gradient manipulation are shown to influence chromatographic resolution and retention. The HT-SGIC investigations are complemented by HT-TGIC separations where a solvent mixture of decane and cyclohexanone is used as the mobile phase in isocratic mode. It is shown that HT-SGIC and HT-TGIC provide different types of separation, however, both are predominantly based on differences in functionality. To provide comprehensive information on chemical composition (functionality) and molar mass, HT-SGIC and HT-TGIC are coupled to HT-SEC, using ortho-dichlorobenzene as the second dimension mobile phase. Clear differences between oxidized and nonoxidized waxes are detected in HT-2D-LC providing comprehensive information on the molecular heterogeneity of these materials.
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Affiliation(s)
- Anthony Ndiripo
- Department of Chemistry and Polymer Science , University of Stellenbosch , 7602 Matieland , South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science , University of Stellenbosch , 7602 Matieland , South Africa
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33
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Ndiripo A, Pasch H. A multidimensional fractionation protocol for the oligomer analysis of oxidized waxes. Anal Chim Acta 2018; 1027:137-148. [PMID: 29866263 DOI: 10.1016/j.aca.2018.03.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/28/2018] [Accepted: 03/02/2018] [Indexed: 11/29/2022]
Abstract
Oxidized waxes possess far superior properties as compared to the alkanes they are derived from. The separation of alkane oligomers via gas chromatography (GC) becomes a challenge when polar oxygen-containing functional groups are introduced or when higher molar masses are targeted. In the present study, the separation and analysis of oligomers in oxidized and non-oxidized waxes using different liquid chromatographic techniques are investigated. Oligomers in two oxidized waxes and a non-oxidized wax from which they are derived, are separated using high-temperature solvent gradient interaction chromatography (HT-SGIC) and high-temperature two-dimensional liquid chromatography (HT-2D-LC). Evaporative light scattering detector conditions are tailored to provide the best detection with the solvent system at use. It is shown that oligomers in oxidized and non-oxidized waxes can be separated and identified using the mentioned techniques. It has been found that the ELSD detector response systematically decreases as the oxidation levels of the waxes increase. Coupling of HT-HPLC and high-temperature size exclusion chromatography (HT-SEC) in a comprehensive 2D-LC setup shows a broadening of the molar mass distributions of the lower oligomer fractions as a consequence of the modification indicating changes in the oligomer chain microstructures. A preparative fractionation technique is utilized to collect specific oligomer fractions from the bulk waxes followed by hyphenation to HT-HPLC and other techniques. HPLC is shown to provide more detailed information on the oligomer composition of waxes when coupled to a pre-fractionation technique.
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Affiliation(s)
- Anthony Ndiripo
- Department of Chemistry and Polymer Science, University of Stellenbosch, 7602, Matieland, South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science, University of Stellenbosch, 7602, Matieland, South Africa.
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34
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Affiliation(s)
- Anthony Ndiripo
- Department of Chemistry and Polymer Science; University of Stellenbosch; Stellenbosch South Africa
| | | | - Harald Pasch
- Department of Chemistry and Polymer Science; University of Stellenbosch; Stellenbosch South Africa
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35
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Ndiripo A, Albrecht A, Monrabal B, Wang J, Pasch H. Chemical Composition Fractionation of Olefin Plastomers/Elastomers by Solvent and Thermal Gradient Interaction Chromatography. Macromol Rapid Commun 2018; 39:e1700703. [DOI: 10.1002/marc.201700703] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 12/04/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Anthony Ndiripo
- Department of Chemistry and Polymer Science; University of Stellenbosch; Private Bag X1 Matieland 7602 South Africa
| | - Andreas Albrecht
- Borealis Polyolefine GmbH; St. Peter-Strasse 25 4021 Linz Austria
| | - Benjamin Monrabal
- Polymer Char; Valencia Technology Park; Gustave Eiffel 8 46980 Paterna Spain
| | - Jingbo Wang
- Borealis Polyolefine GmbH; St. Peter-Strasse 25 4021 Linz Austria
| | - Harald Pasch
- Department of Chemistry and Polymer Science; University of Stellenbosch; Private Bag X1 Matieland 7602 South Africa
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36
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Abstract
The multiple preparative fractionation concept provides sample libraries with different degrees of branching and different molar masses that are analyzed regarding the LDPE microstructure.
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Affiliation(s)
- P. S. Eselem Bungu
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- 7602 Stellenbosch
- South Africa
| | - H. Pasch
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- 7602 Stellenbosch
- South Africa
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37
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Eselem Bungu PS, Pflug K, Pasch H. Combination of preparative and two-dimensional chromatographic fractionation with thermal analysis for the branching analysis of polyethylene. Polym Chem 2018. [DOI: 10.1039/c8py00522b] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multiple preparative fractionation of LDPE provides molar mass and branching fractions that are analyzed regarding their thermal properties.
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Affiliation(s)
- Paul S. Eselem Bungu
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- 7602 Matieland
- South Africa
| | - Kristina Pflug
- Technical Chemistry III
- Technical University Darmstadt
- 64287 Darmstadt
- Germany
| | - Harald Pasch
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- 7602 Matieland
- South Africa
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38
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Eselem Bungu PS, Pflug K, Busch M, Pasch H. Comprehensive analysis of novel grafted polyethylenes using multidimensional fractionation methods. Polym Chem 2018. [DOI: 10.1039/c8py01122b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Noval graft copolymers HDPE-g-LDPE were prepared using a dual reactor setup and characterized regarding molar mass, branching and grafting efficiency using a multidimensional analytical approach.
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Affiliation(s)
- Paul S. Eselem Bungu
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- 7602 Matieland
- South Africa
| | - Kristina Pflug
- Ernst-Berl-Institute of Technical Chemistry
- Technical University Darmstadt
- 64287 Darmstadt
- Germany
| | - Markus Busch
- Ernst-Berl-Institute of Technical Chemistry
- Technical University Darmstadt
- 64287 Darmstadt
- Germany
| | - Harald Pasch
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- 7602 Matieland
- South Africa
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39
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Greyling G, Pasch H. Characterization of charged polymer self-assemblies by multidetector thermal field-flow fractionation in aqueous mobile phases. J Chromatogr A 2017; 1532:175-181. [PMID: 29223324 DOI: 10.1016/j.chroma.2017.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 11/15/2022]
Abstract
Charged block copolymer self-assemblies, such as charged micelles, have attracted much attention as versatile drug delivery systems due to their readily tunable characteristics such as size and surface charge. However, current column-based analytical techniques are not suitable to fractionate and comprehensively characterize charged micelles in terms of size, molar mass, chemical composition and morphology. Multidetector thermal field-flow fractionation (ThFFF) is shown to be a unique characterization platform that can be used to characterize charged micelles in terms of size, molar mass, chemical composition and morphology in aqueous mobile phases with various ionic strengths and pH. This is demonstrated by the characterization of poly(methacrylic acid)-b-poly(methyl methacrylate) self-assemblies in high pH buffers as well as the characterization of cationic poly(2-vinyl pyridine)-b-polystyrene and poly(4-vinyl pyridine)-b-polystyrene self-assemblies in low pH buffers. Moreover, it is shown that ThFFF is capable of separating charged micelles according to the corona composition. These investigations prove convincingly that ThFFF is broadly applicable to the comprehensive characterization of amphiphilic self-assemblies even when aqueous mobile phases are used.
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Affiliation(s)
- Guilaume Greyling
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602, Stellenbosch, South Africa.
| | - Harald Pasch
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602, Stellenbosch, South Africa
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40
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Liu Y, Phiri MJ, Ndiripo A, Pasch H. Chemical composition separation of a propylene–ethylene random copolymer by high temperature solvent gradient interaction chromatography. J Chromatogr A 2017; 1522:23-29. [DOI: 10.1016/j.chroma.2017.09.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 06/04/2017] [Accepted: 09/19/2017] [Indexed: 11/30/2022]
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41
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Greyling G, Pasch H. Fractionation of poly(methacrylic acid) and poly(vinyl pyridine) in aqueous and organic mobile phases by multidetector thermal field-flow fractionation. J Chromatogr A 2017; 1512:115-123. [PMID: 28716356 DOI: 10.1016/j.chroma.2017.07.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 11/26/2022]
Abstract
Multidetector thermal field-flow fractionation (ThFFF) is shown to be a versatile characterisation platform that can be used to characterise hydrophilic polymers in a variety of organic and aqueous solutions with various ionic strengths. It is demonstrated that ThFFF fractionates isotactic and syndiotactic poly(methacrylic acid) (PMAA) as well as poly(2-vinyl pyridine) (P2VP) and poly(4-vinyl pyridine) (P4VP) according to microstructure in organic solvents and that the ionic strength of the mobile phase has no influence on the retention behaviour of the polymers. With regard to aqueous solutions, it is shown that, despite the weak retention, isotactic and syndiotactic PMAA show different retention behaviours which can qualitatively be attributed to microstructure. Additionally, it is shown that the ionic strength of the mobile phase has a significant influence on the thermal diffusion of polyelectrolytes in aqueous solutions and that the addition of an electrolyte is essential to achieve a microstructure-based separation of P2VP and P4VP in aqueous solutions.
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Affiliation(s)
- Guilaume Greyling
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Stellenbosch, South Africa.
| | - Harald Pasch
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Stellenbosch, South Africa
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42
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Muza UL, Greyling G, Pasch H. Characterization of Complex Polymer Self-Assemblies and Large Aggregates by Multidetector Thermal Field-Flow Fractionation. Anal Chem 2017; 89:7216-7224. [DOI: 10.1021/acs.analchem.7b01445] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Upenyu L. Muza
- Department of Chemistry and
Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa
| | - Guilaume Greyling
- Department of Chemistry and
Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa
| | - Harald Pasch
- Department of Chemistry and
Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa
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43
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Affiliation(s)
- Guilaume Greyling
- Department of Chemistry and Polymer Science; University of Stellenbosch; South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science; University of Stellenbosch; South Africa
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44
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Affiliation(s)
- Guilaume Greyling
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa
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45
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Abstract
A concept for the comprehensive analysis of branched polyethylene is developed where a multiple fractionation protocol is used.
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Affiliation(s)
- P. S. Eselem Bungu
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- 7602 Matieland
- South Africa
| | - H. Pasch
- Department of Chemistry and Polymer Science
- University of Stellenbosch
- 7602 Matieland
- South Africa
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46
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47
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Makan AC, Williams RP, Pasch H. Field Flow Fractionation for the Size, Molar Mass, and Gel Content Analysis of Emulsion Polymers for Water-Based Coatings. MACROMOL CHEM PHYS 2016. [DOI: 10.1002/macp.201600208] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ashwell C. Makan
- Kansai Plascon Research Centre; Polymer Science Building, Room 2028; University of Stellenbosch; 7602 Matieland South Africa
- Department of Chemistry and Polymer Science; University of Stellenbosch; Private Bag X1 Matieland 7602 South Africa
| | - Ryan P. Williams
- Kansai Plascon Research Centre; Polymer Science Building, Room 2028; University of Stellenbosch; 7602 Matieland South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science; University of Stellenbosch; Private Bag X1 Matieland 7602 South Africa
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48
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Makan AC, Spallek MJ, du Toit M, Klein T, Pasch H. Advanced analysis of polymer emulsions: Particle size and particle size distribution by field-flow fractionation and dynamic light scattering. J Chromatogr A 2016; 1442:94-106. [DOI: 10.1016/j.chroma.2016.03.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 02/19/2016] [Accepted: 03/06/2016] [Indexed: 12/01/2022]
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49
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Greyling G, Pasch H. Multidetector Thermal Field-Flow Fractionation: A Unique Tool for Monitoring the Structure and Dynamics of Block Copolymer Micelles. Macromolecules 2016. [DOI: 10.1021/acs.macromol.5b02634] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guilaume Greyling
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602, Stellenbosch, South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, 7602, Stellenbosch, South Africa
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Phiri MJ, Pasch H. Exploring the Compositional Heterogeneity of Vis-Broken Impact Poly(propylene) Copolymers by Advanced Fractionation Methods. MACROMOL CHEM PHYS 2016. [DOI: 10.1002/macp.201500470] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Mohau Justice Phiri
- Department of Chemistry and Polymer Science; Stellenbosch University; 7602 Matieland South Africa
| | - Harald Pasch
- Department of Chemistry and Polymer Science; Stellenbosch University; 7602 Matieland South Africa
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