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Feng XJ, Tang YJ, Yang Y, Wang G, Mei P, Lai L. Relationship between the dynamic interfacial activity and demulsification performance of hyperbranched poly(amido amine) polyethers. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2021.127869] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Sabatino P, Gao M, Hou J. Quantitative adiabatic-refocused INEPT (QA-RINEPT) as a tool for fast and reliable characterization of polyols. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:1149-1157. [PMID: 29949187 DOI: 10.1002/mrc.4777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 06/08/2023]
Abstract
13 C nuclear magnetic resonance (NMR) is a powerful tool for the detailed characterization and structure elucidation of polymeric samples. The low natural abundance and sensitivity of the 13 C isotope, however, lead to very long acquisition time, therefore limiting the use of such technique. We report here the implementation of a quantitative method, quantitative adiabatic-refocused insensitive nuclei enhanced by polarization transfer (QA-RINEPT), for the characterization of polyol samples. The method, based on the well-known insensitive nuclei enhanced by polarization transfer sequence, allows the boost in sensitivity of the carbon resonances without sacrificing the quantitative aspects of the analysis. This is achieved controlling the polarization transfer mechanism and introducing a response factor to calculate precisely the sensitivity gain of the different carbon signals. Compared with the standard single pulse quantitative experiment, the QA-RINEPT method produces up to 4.7× signals enhancement per unit of time. An in-depth statistical analysis was conducted to confirm the reliability of the QA-RINEPT method. We show that there is excellent agreement between the new and old 13 C-NMR methods for the quantitative determination of several important polyol properties such as the comonomer and initiator content as well as the ratio of primary and secondary hydroxyl groups.
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Affiliation(s)
- Paolo Sabatino
- Corporate R&D, Dow Benelux B. V, Terneuzen, The Netherlands
| | - Min Gao
- Corporate R&D, The Dow Chemical Company, Freeport, Texas, USA
| | - Jianbo Hou
- Corporate R&D, The Dow Chemical Company, Midland, Michigan, USA
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Synthesis, aggregation behavior, and simvastatin solubilization by block polyethers with different structures. Colloid Polym Sci 2018. [DOI: 10.1007/s00396-018-4341-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Xue Y, Sun J, Xiong S, Liu T, Xin X, Xu G. Synthesis, self-assembly and drug solubilization of hyperbranched block polyethers. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.11.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Zientek N, Laurain C, Meyer K, Paul A, Engel D, Guthausen G, Kraume M, Maiwald M. Automated data evaluation and modelling of simultaneous (19) F-(1) H medium-resolution NMR spectra for online reaction monitoring. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:513-520. [PMID: 25854892 DOI: 10.1002/mrc.4216] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 10/31/2014] [Accepted: 01/19/2015] [Indexed: 06/04/2023]
Abstract
Medium-resolution nuclear magnetic resonance spectroscopy (MR-NMR) currently develops to an important analytical tool for both quality control and process monitoring. In contrast to high-resolution online NMR (HR-NMR), MR-NMR can be operated under rough environmental conditions. A continuous re-circulating stream of reaction mixture from the reaction vessel to the NMR spectrometer enables a non-invasive, volume integrating online analysis of reactants and products. Here, we investigate the esterification of 2,2,2-trifluoroethanol with acetic acid to 2,2,2-trifluoroethyl acetate both by (1) H HR-NMR (500 MHz) and (1) H and (19) F MR-NMR (43 MHz) as a model system. The parallel online measurement is realised by splitting the flow, which allows the adjustment of quantitative and independent flow rates, both in the HR-NMR probe as well as in the MR-NMR probe, in addition to a fast bypass line back to the reactor. One of the fundamental acceptance criteria for online MR-MNR spectroscopy is a robust data treatment and evaluation strategy with the potential for automation. The MR-NMR spectra are treated by an automated baseline and phase correction using the minimum entropy method. The evaluation strategies comprise (i) direct integration, (ii) automated line fitting, (iii) indirect hard modelling (IHM) and (iv) partial least squares regression (PLS-R). To assess the potential of these evaluation strategies for MR-NMR, prediction results are compared with the line fitting data derived from the quantitative HR-NMR spectroscopy. Although, superior results are obtained from both IHM and PLS-R for (1) H MR-NMR, especially the latter demands for elaborate data pretreatment, whereas IHM models needed no previous alignment. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Nicolai Zientek
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Straße 11, 12489, Berlin, Germany
| | - Clément Laurain
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Straße 11, 12489, Berlin, Germany
- École Nationale Supérieure de Chimie de Lille, Avenue Mendeleiev CS 90108, 59652, Villeneuve D'ascq Cedex, France
| | - Klas Meyer
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Straße 11, 12489, Berlin, Germany
| | - Andrea Paul
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Straße 11, 12489, Berlin, Germany
| | - Dirk Engel
- Pro2NMR, Institute of Mechanical Process Engineering and Mechanics and Institute of Biological Interfaces, KIT, Adenauerring 20b, 76131, Karlsruhe, Germany
| | | | - Matthias Kraume
- Department of Chemical Engineering, Technische Universität Berlin, Straße des 17. Juni 136, MA 5-7, 10623, Berlin, Germany
| | - Michael Maiwald
- BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Straße 11, 12489, Berlin, Germany
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Mitchell J, Gladden LF, Chandrasekera TC, Fordham EJ. Low-field permanent magnets for industrial process and quality control. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 76:1-60. [PMID: 24360243 DOI: 10.1016/j.pnmrs.2013.09.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/19/2013] [Accepted: 09/19/2013] [Indexed: 05/13/2023]
Abstract
In this review we focus on the technology associated with low-field NMR. We present the current state-of-the-art in low-field NMR hardware and experiments, considering general magnet designs, rf performance, data processing and interpretation. We provide guidance on obtaining the optimum results from these instruments, along with an introduction for those new to low-field NMR. The applications of lowfield NMR are now many and diverse. Furthermore, niche applications have spawned unique magnet designs to accommodate the extremes of operating environment or sample geometry. Trying to capture all the applications, methods, and hardware encompassed by low-field NMR would be a daunting task and likely of little interest to researchers or industrialists working in specific subject areas. Instead we discuss only a few applications to highlight uses of the hardware and experiments in an industrial environment. For details on more particular methods and applications, we provide citations to specialized review articles.
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Affiliation(s)
- J Mitchell
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom; Schlumberger Gould Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
| | - L F Gladden
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom.
| | - T C Chandrasekera
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom
| | - E J Fordham
- Schlumberger Gould Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
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Dalitz F, Cudaj M, Maiwald M, Guthausen G. Process and reaction monitoring by low-field NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2012; 60:52-70. [PMID: 22293399 DOI: 10.1016/j.pnmrs.2011.11.003] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 11/29/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Franz Dalitz
- Institute of Mechanical Process Engineering and Mechanics, SRG10-2, KIT, Adenauerring 20 b, 76131 Karlsruhe, Germany
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Antalek B. Accounting for Spin Relaxation in Quantitative Pulse Gradient Spin Echo NMR Mixture Analysis. J Am Chem Soc 2006; 128:8402-3. [PMID: 16802797 DOI: 10.1021/ja062592c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pulsed gradient spin-echo (PGSE) NMR is intrinsically nonquantitative. Because the experiment is echo-based, differences in the relaxation behavior of the nuclei among the components give rise to varied intensities and lead to nonquantitative spectra. A method is presented that restores resolved, quantitative spectra from mixtures by processing data from several PGSE NMR experiments with varied delay times. The approach incorporates a simple data acquisition scheme and leads to a computationally fast, linear least-squares analysis. It is anticipated the method will be of much interest for performing mixture analysis of polymer solutions and the characterization of surface-modified nanoparticulate dispersions.
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Affiliation(s)
- Brian Antalek
- Research and Development, Eastman Kodak Company, 1999 Lake Avenue, Rochester, NY 14650-2132, USA.
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Vega-Montoto L, Wentzell PD. Approaching the direct exponential curve resolution algorithm from a maximum likelihood perspective. Anal Chim Acta 2006. [DOI: 10.1016/j.aca.2005.09.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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