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Cahill JF, Kertesz V, Saint-Vincent P, Valentino H, Drufva E, Thiele N, Michener JK. High-Throughput Characterization and Optimization of Polyamide Hydrolase Activity Using Open Port Sampling Interface Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023. [PMID: 37262418 DOI: 10.1021/jasms.3c00097] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Enzymatic biodegradation of polymers, such as polyamides (PA), has the potential to cost-effectively reduce plastic waste, but enhancements in degradation efficiency are needed. Engineering enzymes through directed evolution is one pathway toward identification of critical domains needed for improving activity. However, screening such enzymatic libraries (100s-to-1000s of samples) is time-consuming. Here we demonstrate the use of robotic autosampler (PAL) and immediate drop on demand technology (I.DOT) liquid handling systems coupled with open-port sampling interface-mass spectrometry (OPSI-MS) to screen for PA6 and PA66 hydrolysis by 6-aminohexanoate-oligomer endo-hydrolase (nylon hydrolase, NylC) in a high-throughput (8-20 s/sample) manner. The OPSI-MS technique required minimal sample preparation and was amenable to 96-well plate formats for automated processing. Enzymatic hydrolysis of PA characteristically produced soluble linear oligomer products that could be identified by OPSI-MS. Incubation temperatures and times were optimized for PA6 (65 °C, 24 h) and PA66 (75 °C, 24 h) over 108 experiments. In addition, the I.DOT/OPSI-MS quantified production of PA6 linear dimer (8.3 ± 1.6 μg/mL) and PA66 linear monomer (13.5 ± 1.5 μg/mL) by NylC with a lower limit of detection of 0.029 and 0.032 μg/mL, respectively. For PA6 and PA66, linear oligomer production corresponded to 0.096 ± 0.018% and 0.204 ± 0.028% conversion of dry pellet mass, respectively. The developed methodology is expected to be utilized to assess enzymatic hydrolysis of engineered enzyme libraries, comprising hundreds to thousands of individual samples.
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Affiliation(s)
- John F Cahill
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6131, United States
| | - Vilmos Kertesz
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6131, United States
| | - Patricia Saint-Vincent
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6131, United States
| | - Hannah Valentino
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6131, United States
| | - Erin Drufva
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6131, United States
| | - Nikki Thiele
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6131, United States
| | - Joshua K Michener
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6131, United States
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2
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Niezen LE, Kruijswijk JD, van Henten GB, Pirok BWJ, Staal BBP, Radke W, Philipsen HJA, Somsen GW, Schoenmakers PJ. Principles and potential of solvent gradient size-exclusion chromatography for polymer analysis. Anal Chim Acta 2023; 1253:341041. [PMID: 36965990 DOI: 10.1016/j.aca.2023.341041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/06/2023]
Abstract
The properties of a polymeric material are influenced by its underlying molecular distributions, including the molecular-weight (MWD), chemical-composition (CCD), and/or block-length (BLD) distributions. Gradient-elution liquid chromatography (LC) is commonly used to determine the CCD. Due to the limited solubility of polymers, samples are often dissolved in strong solvents. Upon injection of the sample, such solvents may lead to broadened or poorly shaped peaks and, in unfavourable cases, to "breakthrough" phenomena, where a part of the sample travels through the column unretained. To remedy this, a technique called size-exclusion-chromatography gradients or gradient size-exclusion chromatography (gSEC) was developed in 2011. In this work, we aim to further explore the potential of gSEC for the analysis of the CCD, also in comparison with conventional gradient-elution reversed-phase LC, which in this work corresponded to gradient-elution reversed-phase liquid chromatography (RPLC). The influence of the mobile-phase composition, the pore size of the stationary-phase particles, and the column temperature were investigated. The separation of five styrene/ethyl acrylate copolymers was studied with one-dimensional RPLC and gSEC. RPLC was shown to lead to a more-accurate CCD in shorter analysis time. The separation of five styrene/methyl methacrylate copolymers was also explored using comprehensive two-dimensional (2D) LC involving gSEC, i.e. SEC × gSEC and SEC × RPLC. In 2D-LC, the use of gSEC was especially advantageous as no breakthrough could occur.
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Affiliation(s)
- Leon E Niezen
- Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands.
| | - Jordy D Kruijswijk
- Centre for Analytical Sciences Amsterdam (CASA), the Netherlands; Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Gerben B van Henten
- Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands
| | - Bob W J Pirok
- Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands
| | | | - Wolfgang Radke
- PSS Polymer Standards Service, In der Dalheimer Wiese 5, 55120, Mainz, Germany
| | - Harry J A Philipsen
- DSM Engineering Materials, Urmonderbaan 22, 6167 RD, Geleen, the Netherlands
| | - Govert W Somsen
- Centre for Analytical Sciences Amsterdam (CASA), the Netherlands; Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Peter J Schoenmakers
- Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands
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3
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Zhong S, Guo Y, Gao F, Lin Q, Wang Y, Chen W, Lu W. Studies of caprolactam and cyclic oligomer content, molecular weight, and thermal properties during melt post-polycondensation of polycaprolactam in the film state. POLYMER 2023. [DOI: 10.1016/j.polymer.2023.125802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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4
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Gudeangadi PG, Sakamoto T, Shichibu Y, Konishi K, Nakano T. Chiral Polyurethane Synthesis Leading to π-Stacked 2/1-Helical Polymer and Cyclic Compounds. ACS Macro Lett 2015; 4:901-906. [PMID: 35596455 DOI: 10.1021/acsmacrolett.5b00477] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
(R)-1,1'-Bi(2-naphthol) was reacted with 1,4-phenylene diisocyanate leading to a mixture of linear polyurethane and cyclic compounds including a cyclic dimer and a cyclic trimer. The structure of the cyclic dimer was elucidated by X-ray crystal structure analysis. The polymer was proposed to possess a rather stiff, π-stacked, 2/1-helical conformation on the basis of NMR, CD, and UV spectra and molecular dynamics simulations. The conformation was stable in the range of temperature of 0-60 °C.
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Affiliation(s)
- Prashant G. Gudeangadi
- Catalysis
Research Center (CRC) and Graduate School of Chemical Sciences and
Engineering, Hokkaido University, N21, W10, Kita-ku, Sapporo 001-0021, Japan
| | - Takeshi Sakamoto
- Catalysis
Research Center (CRC) and Graduate School of Chemical Sciences and
Engineering, Hokkaido University, N21, W10, Kita-ku, Sapporo 001-0021, Japan
| | - Yukatsu Shichibu
- Faculty
of Environmental Earth Sciences, Hokkaido University, N10, W5,
Kita-ku, Sapporo 060-0810, Japan
| | - Katsuaki Konishi
- Faculty
of Environmental Earth Sciences, Hokkaido University, N10, W5,
Kita-ku, Sapporo 060-0810, Japan
| | - Tamaki Nakano
- Catalysis
Research Center (CRC) and Graduate School of Chemical Sciences and
Engineering, Hokkaido University, N21, W10, Kita-ku, Sapporo 001-0021, Japan
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5
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Ghaffar A, Draaisma G, Mihov G, Schoenmakers P, van der Wal S. A versatile system for studying the enzymatic degradation of multi-block poly(ester amide)s. J Chromatogr A 2013; 1286:29-40. [DOI: 10.1016/j.chroma.2013.02.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 02/04/2013] [Accepted: 02/06/2013] [Indexed: 12/01/2022]
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6
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Heimrich M, Bönsch M, Nickl H, Simat T. Cyclic oligomers in polyamide for food contact material: quantification by HPLC‐CLND and single‐substance calibration. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2012; 29:846-60. [DOI: 10.1080/19440049.2011.649496] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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7
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Sanchez AC, Anspach JA, Farkas T. Performance optimizing injection sequence for minimizing injection band broadening contributions in high efficiency liquid chromatographic separations. J Chromatogr A 2012; 1228:338-48. [DOI: 10.1016/j.chroma.2012.01.038] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 01/13/2012] [Accepted: 01/16/2012] [Indexed: 11/30/2022]
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8
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Uliyanchenko E, van der Wal S, Schoenmakers PJ. Challenges in polymer analysis by liquid chromatography. Polym Chem 2012. [DOI: 10.1039/c2py20274c] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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9
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10
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Preparation of tea catechins using polyamide. J Biosci Bioeng 2011; 111:232-6. [DOI: 10.1016/j.jbiosc.2010.09.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 09/29/2010] [Accepted: 09/30/2010] [Indexed: 11/18/2022]
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11
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Miramon H, Cavelier F, Martinez J, Cottet H. Highly Resolutive Separations of Hardly Soluble Synthetic Polypeptides by Capillary Electrophoresis. Anal Chem 2009; 82:394-9. [DOI: 10.1021/ac902211f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Hélène Miramon
- Institut des Biomolécules Max Mousseron (IBMM, UMR 5247 CNRS − Université de Montpellier 1 − Université de Montpellier 2), place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5, France
| | - Florine Cavelier
- Institut des Biomolécules Max Mousseron (IBMM, UMR 5247 CNRS − Université de Montpellier 1 − Université de Montpellier 2), place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5, France
| | - Jean Martinez
- Institut des Biomolécules Max Mousseron (IBMM, UMR 5247 CNRS − Université de Montpellier 1 − Université de Montpellier 2), place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5, France
| | - Hervé Cottet
- Institut des Biomolécules Max Mousseron (IBMM, UMR 5247 CNRS − Université de Montpellier 1 − Université de Montpellier 2), place Eugène Bataillon, case courrier 1706, 34095 Montpellier Cedex 5, France
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12
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Ricco L, Casazza E, Mineo P, Russo S, Scamporrino E. Nature of a Low Molar Mass Peak in Anionic Poly(ε-caprolactam). Main Aspects of Its Formation. Macromolecules 2008. [DOI: 10.1021/ma800238c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Laura Ricco
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
| | - Elena Casazza
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
| | - Placido Mineo
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
| | - Saverio Russo
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
| | - Emilio Scamporrino
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
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13
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Casazza E, Ricco L, Russo S, Scamporrino E. Nature of a Low Molar Mass Peak in Anionic Poly(ε-caprolactam). Its Identification as Macrocyclic Ensemble. Macromolecules 2007. [DOI: 10.1021/ma0623901] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elena Casazza
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
| | - Laura Ricco
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
| | - Saverio Russo
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
| | - Emilio Scamporrino
- Dipartimento di Chimica e Chimica Industriale, Università di Genova and INSTM NIPLAB Centre, Via Dodecaneso 31, 16146 Genova, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria, 6, 95125 Catania, Italy
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14
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Jiang X, van der Horst A, Schoenmakers PJ. Breakthrough of polymers in interactive liquid chromatography. J Chromatogr A 2002; 982:55-68. [PMID: 12489856 DOI: 10.1016/s0021-9673(02)01483-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Two separate peaks are observed for narrow polymer standards in both isocratic and gradient HPLC. One peak appears around the solvent front (the "solvent-plug peak" or "breakthrough peak"), whereas the second peak is retained significantly--or even highly. Although the effect has been observed many times before, it has never been rigorously explained. In this paper we provide a detailed explanation for the breakthrough peak. The two completely separate peaks are demonstrated not to represent to different fractions of the sample (e.g., the low- and high-molecular-mass parts of the distribution). Both peaks are representative of the entire polymeric sample for narrow polymer standard. Because the amount of the polymer in the breakthrough peak may vary, the quantitative analysis of the polymers by LC is jeopardized. The effects of the sample solvent, the (initial) mobile phase composition, the injection volume, the injected sample concentration, the column temperature, and the analyte structure and molecular mass on the breakthrough peak were investigated in LC experiments involving standards of polystyrene and poly(methyl methacrylate). Three necessary and sufficient conditionsare suggested for the breakthrough phenomenon to be observed. Recommendations to avoid the breakthrough phenomenon are given, culminating in a structured method for selecting the best possible sample solvents.
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Affiliation(s)
- Xulin Jiang
- Polymer-Analysis Group, Department of Chemical Engineering, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
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15
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Mengerink Y, Peters R, van der Wal S, Claessens HA, Cramers CA. Analysis of linear and cyclic oligomers in polyamide-6 without sample preparation by liquid chromatography using the sandwich injection method. III. Separation mechanism and gradient optimization. J Chromatogr A 2002; 949:307-26. [PMID: 11999748 DOI: 10.1016/s0021-9673(01)01440-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The first six linear and cyclic oligomers of polyamide-6 can be quantitatively determined in the polymer using HPLC with the sandwich injection method and an aqueous acetonitrile gradient. In this final part of the triptych concerning the determination of the oligomers in polyamide-6, the irregular elution behavior of the cyclic monomer compared to the cyclic oligomers was investigated. We also optimized the separation of the involved polyamide oligomers, with respect to gradient steepness, stationary phase, column temperature and mobile phase pH. The irregular elution behavior of the cyclic monomer could be caused by its relatively large exposed/accessible hydrophobic surface, which permits relatively easy penetration into the hydrophobic stationary phase giving extra retention. The dipole moment of the different oligomers was used as a measure for this exposed/accessible hydrophobic area to correlate the retention factors using quantitative structure-retention relationships. We also studied the retention behavior of the polyamide, which is injected each run directly onto the column and modifies the stationary phase. Using a 250-microl post gradient injection zone of formic acid on a 250x3 mm Zorbax SB-C18 column, the polyamide could be effectively removed from the stationary phase after each separation. The linear solvent strength (LSS) model was used to optimize the separation of the first six linear and cyclic oligomers. As the LSS model assumes a linear correlation between the modifier concentration and the logarithm of the retention factor and the cyclic monomer and dimer show extreme curvation of this relation in the eluting region, we investigated different models to predict gradient elution from isocratic data. A direct translation of the isocratic data to gradient retention times did not yield adequate retention times using the LSS model. It was found that the LSS model worked acceptably if gradient retention times were used as input data. Even for fast non-linearly eluting components, an average error of 0.4 resolution units of 4sigma was obtained. Using the LSS model in combination with different column temperatures and mobile phase pH values, a separation of the first six linear and cyclic oligomers was accomplished.
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Affiliation(s)
- Y Mengerink
- MI&Q, DSM Research, Geleen, The Netherlands.
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16
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Peters R, Mengerink Y, Langereis S, Frederix M, Linssen H, van Hest J, van der Wal S. Quantitation of functionality of poly(methyl methacrylate) by liquid chromatography under critical conditions followed by evaporative light-scattering detection. Comparison with NMR and titration. J Chromatogr A 2002; 949:327-35. [PMID: 11999749 DOI: 10.1016/s0021-9673(01)01386-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atom transfer radical polymerisation (ATRP) is a versatile 'living' controlled polymerisation technique for the synthesis of well-defined architectures such as block copolymers, gradient copolymers, hyperbranched polymers and telechelic polymers. ATRP provides control over molecular mass and molecular mass distribution and is suitable for the polymerisation of a wide variety of monomers, including methyl methacrylate. A chromatographic method was developed for an endgroup-based separation of low-molecular-mass poly(methyl methacrylate) (PMMA), based on liquid chromatography under critical conditions. With this method the PMMA, irrespective of its low-molecular-mass, is separated according to endgroups (functionality) due to interactions of the polar endgroups with the non-modified silica based stationary phase. The different series were identified using on-line atmospheric pressure ionisation electrospray mass spectrometry and quantified by evaporative light scattering detection. These results were compared with those obtained by NMR and titration.
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Affiliation(s)
- R Peters
- DSM Research, Competence Center Molecular Identification & Quantification, Geleen, The Netherlands.
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17
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Rissler K, Socher G, Glöckner G. Determination of the molecular weight and other physicochemical properties of poly(bubylene glycol) 1000 by gradient RPHPLC and measurement of the ELSD, UV, and fluorescence responses. Chromatographia 2001. [DOI: 10.1007/bf02492234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Klun U, Andrenšek S, Kržan A. Electrospray mass spectrometry determination of linear and cyclic oligomers of polyamide-6. POLYMER 2001. [DOI: 10.1016/s0032-3861(01)00132-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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19
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Mengerink Y, Peters R, deKoster CG, van der Wal S, Claessens HA, Cramers CA. Separation and quantification of the linear and cyclic structures of polyamide-6 at the critical point of adsorption. J Chromatogr A 2001; 914:131-45. [PMID: 11358207 DOI: 10.1016/s0021-9673(01)00622-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The linear and cyclic structures of polyamide-6 were separated by liquid chromatography at critical conditions (LCCC) and identified with different mass spectrometric (MS) techniques and quantitated by LCCC with evaporative light-scattering detection (ELSD). Electrospray ionization MS was not suitable to identify the higher cyclic structures. For this purpose, matrix-assisted laser desorption ionization time-of-flight MS performed better and cyclic and linear structures were oligomerically resolved and separately identified in the mass spectrometer. The highest cyclic structure present and detected was the cyclic pentacontamer. It could be demonstrated that cyclic and linear oligomers follow different ionization and fragmentation routes/patterns. Quantification with ELSD of the components separated by LCCC using a universal calibration curve or an iterative procedure was developed. An area correction to account for different peak widths of coeluting components improves precision and accuracy of the calibration curve and improves quantitation accuracy for the samples analyzed. With these corrected values, no molecular mass dependency was observed for the cyclic and linear structures. Under critical conditions, the linear and cyclic structures of polyamide-6 were separated, identified and quantified.
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20
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Mengerink Y, Peters R, Kerkhoff M, Hellenbrand J, Omloo H, Andrien J, Vestjens M, van der Wal S. Analysis of linear and cyclic oligomers in polyamide-6 without sample preparation by liquid chromatography using the sandwich injection method. II. Methods of detection and quantification and overall long-term performance. J Chromatogr A 2000; 878:45-55. [PMID: 10843544 DOI: 10.1016/s0021-9673(00)00277-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
By separating the first six linear and cyclic oligomers of polyamide-6 on a reversed-phase high-performance liquid chromatographic system after sandwich injection, quantitative determination of these oligomers becomes feasible. Low-wavelength UV detection of the different oligomers and selective post-column reaction detection of the linear oligomers with o-phthalic dicarboxaldehyde (OPA) and 3-mercaptopropionic acid (3-MPA) are discussed. A general methodology for quantification of oligomers in polymers was developed. It is demonstrated that the empirically determined group-equivalent absorption coefficients and quench factors are a convenient way of quantifying linear and cyclic oligomers of nylon-6. The overall long-term performance of the method was studied by monitoring a reference sample and the calibration factors of the linear and cyclic oligomers.
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Affiliation(s)
- Y Mengerink
- MI&Q, DSM Research, Geleen, The Netherlands.
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