1
|
Morais AF, Radhakrishnan S, Arbiv G, Dom D, Duerinckx K, Chandran CV, Martens JA, Breynaert E. Noncontact In Situ Multidiagnostic NMR/Dielectric Spectroscopy. Anal Chem 2024; 96:5071-5077. [PMID: 38513052 DOI: 10.1021/acs.analchem.3c03007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Introduction of a dielectric material in a nuclear magnetic resonance (NMR) probe head modifies the frequency response of the probe circuit, a phenomenon revealed by detuning of the probe. For NMR spectroscopy, this detuning is corrected for by tuning and matching the probe head prior to the NMR measurement. The magnitude of the probe detuning, "the dielectric shift", provides direct access to the dielectric properties of the sample, enabling NMR spectrometers to simultaneously perform both dielectric and NMR spectroscopy. By measuring sample dielectric permittivity as a function of frequency, dielectric permittivity spectroscopy can be performed using the new methodology. As a proof of concept, this was evaluated on methanol, ethanol, 1-propanol, 1-pentanol, and 1-octanol using a commercial cross-polarization magic angle spinning (CPMAS) NMR probe head. The results accurately match the literature data collected by standard dielectric spectroscopy techniques. Subsequently, the method was also applied to investigate the solvent-surface interactions of water confined in the micropores of an MFI-type, hydrophilic zeolite with a Si/Al ratio of 11.5. In the micropores, water adsorbs to Bro̷nsted acid sites and defect sites, resulting in a drastically decreased dielectric permittivity of the nanoconfined water. Theoretical background for the new methodology is provided using an effective electric circuit model of a CPMAS probe head with a solenoid coil, describing the detuning resulting from the insertion of dielectric samples in the probe head.
Collapse
Affiliation(s)
- Alysson F Morais
- Centre for Surface Chemistry and Catalysis - Characterization and Application Team (COK-KAT), Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Sambhu Radhakrishnan
- Centre for Surface Chemistry and Catalysis - Characterization and Application Team (COK-KAT), Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Gavriel Arbiv
- Centre for Surface Chemistry and Catalysis - Characterization and Application Team (COK-KAT), Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- Center for Molecular Water Science (CMWS), Notkestraße 85, 22607 Hamburg, Germany
| | - Dirk Dom
- Centre for Surface Chemistry and Catalysis - Characterization and Application Team (COK-KAT), Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Karel Duerinckx
- Centre for Surface Chemistry and Catalysis - Characterization and Application Team (COK-KAT), Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - C Vinod Chandran
- Centre for Surface Chemistry and Catalysis - Characterization and Application Team (COK-KAT), Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Johan A Martens
- Centre for Surface Chemistry and Catalysis - Characterization and Application Team (COK-KAT), Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
| | - Eric Breynaert
- Centre for Surface Chemistry and Catalysis - Characterization and Application Team (COK-KAT), Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- NMR for Convergence Research (NMRCoRe), KU Leuven, Celestijnenlaan 200F Box 2461, 3001 Heverlee, Belgium
- Center for Molecular Water Science (CMWS), Notkestraße 85, 22607 Hamburg, Germany
| |
Collapse
|
2
|
Hao S, Yuan J, Wu Q, Liu X, Cui J, Xuan H. Rapid Identification of Corn Sugar Syrup Adulteration in Wolfberry Honey Based on Fluorescence Spectroscopy Coupled with Chemometrics. Foods 2023; 12:2309. [PMID: 37372520 DOI: 10.3390/foods12122309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/06/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Honey adulteration has become a prominent issue in the honey market. Herein, we used the fluorescence spectroscopy combined with chemometrics to explore a simple, fast, and non-destructive method to detect wolfberry honey adulteration. The main parameters such as the maximum fluorescence intensity, peak positions, and fluorescence lifetime were analyzed and depicted with a principal component analysis (PCA). We demonstrated that the peak position of the wolfberry honey was relatively fixed at 342 nm compared with those of the multifloral honey. The fluorescence intensity decreased and the peak position redshifted with an increase in the syrup concentration (10-100%). The three-dimensional (3D) spectra and fluorescence lifetime fitting plots could obviously distinguish the honey from syrups. It was difficult to distinguish the wolfberry honey from another monofloral honey, acacia honey, using fluorescence spectra, but it could easily be distinguished when the fluorescence data were combined with a PCA. In all, fluorescence spectroscopy coupled with a PCA could easily distinguish wolfberry honey adulteration with syrups or other monofloral honeys. The method was simple, fast, and non-destructive, with a significant potential for the detection of honey adulteration.
Collapse
Affiliation(s)
- Shengyu Hao
- School of Physical Science and Information Technology, Liaocheng University, Liaocheng 252059, China
| | - Jie Yuan
- School of Life Sciences, Liaocheng University, Liaocheng 252059, China
| | - Qian Wu
- School of Life Sciences, Liaocheng University, Liaocheng 252059, China
| | - Xinying Liu
- Animal Product Quality and Safety Center of Shandong Province, Jinan 250010, China
| | - Jichun Cui
- School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China
| | - Hongzhuan Xuan
- School of Life Sciences, Liaocheng University, Liaocheng 252059, China
| |
Collapse
|
3
|
Stajcic I, Veljkovic F, Petrovic M, Veličkovic S, Radojevic V, Vlahović B, Stajcic A. Impact- and Thermal-Resistant Epoxy Resin Toughened with Acacia Honey. Polymers (Basel) 2023; 15:polym15102261. [PMID: 37242836 DOI: 10.3390/polym15102261] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 04/26/2023] [Accepted: 04/29/2023] [Indexed: 05/28/2023] Open
Abstract
High performance polymers with bio-based modifiers are promising materials in terms of applications and environmental impact. In this work, raw acacia honey was used as a bio-modifier for epoxy resin, as a rich source of functional groups. The addition of honey resulted in the formation of highly stable structures that were observed in scanning electron microscopy images as separate phases at the fracture surface, which were involved in the toughening of the resin. Structural changes were investigated, revealing the formation of a new aldehyde carbonyl group. Thermal analysis confirmed the formation of products that were stable up to 600 °C, with a glass transition temperature of 228 °C. An energy-controlled impact test was performed to compare the absorbed impact energy of bio-modified epoxy containing different amounts of honey with unmodified epoxy resin. The results showed that bio-modified epoxy resin with 3 wt% of acacia honey could withstand several impacts with full recovery, while unmodified epoxy resin broke at first impact. The absorbed energy at first impact was 2.5 times higher for bio-modified epoxy resin than it was for unmodified epoxy resin. In this manner, by using simple preparation and a raw material that is abundant in nature, a novel epoxy with high thermal and impact resistance was obtained, opening a path for further research in this field.
Collapse
Affiliation(s)
- Ivana Stajcic
- Department of Physical Chemistry, "Vinča" Institute of Nuclear Sciences-National Institute of the Republic of Serbia, University of Belgrade, Mike Petrovića Alasa 12-14, P.O. Box 522, 11001 Belgrade, Serbia
| | - Filip Veljkovic
- Department of Physical Chemistry, "Vinča" Institute of Nuclear Sciences-National Institute of the Republic of Serbia, University of Belgrade, Mike Petrovića Alasa 12-14, P.O. Box 522, 11001 Belgrade, Serbia
| | - Milos Petrovic
- Faculty of Technology and Metallurgy, University of Belgrade, 11000 Belgrade, Serbia
| | - Suzana Veličkovic
- Department of Physical Chemistry, "Vinča" Institute of Nuclear Sciences-National Institute of the Republic of Serbia, University of Belgrade, Mike Petrovića Alasa 12-14, P.O. Box 522, 11001 Belgrade, Serbia
| | - Vesna Radojevic
- Faculty of Technology and Metallurgy, University of Belgrade, 11000 Belgrade, Serbia
| | - Branislav Vlahović
- Mathematics and Physics Department, North Carolina Central University, Durham, NC 27707, USA
| | - Aleksandar Stajcic
- Center for Microelectronic Technologies, Institute of Chemistry, Technology and Metallurgy-National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia
| |
Collapse
|
4
|
Shi J, Liang J, Pu J, Li Z, Zou X. Nondestructive detection of the bioactive components and nutritional value in restructured functional foods. Curr Opin Food Sci 2023. [DOI: 10.1016/j.cofs.2022.100986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
|
5
|
Classification of Polish Natural Bee Honeys Based on Their Chemical Composition. Molecules 2022; 27:molecules27154844. [PMID: 35956789 PMCID: PMC9369904 DOI: 10.3390/molecules27154844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/20/2022] [Accepted: 07/27/2022] [Indexed: 12/04/2022] Open
Abstract
The targeted quantitative NMR (qNMR) approach is a powerful analytical tool, which can be applied to classify and/or determine the authenticity of honey samples. In our study, this technique was used to determine the chemical profiles of different types of Polish honey samples, featured by variable contents of main sugars, free amino acids, and 5-(hydroxymethyl)furfural. One-way analysis of variance (ANOVA) was performed on concentrations of selected compounds to determine significant differences in their levels between all types of honey. For pattern recognition, principal component analysis (PCA) was conducted and good separations between all honey samples were obtained. The results of present studies allow the differentiation of honey samples based on the content of sucrose, glucose, and fructose, as well as amino acids such as tyrosine, phenylalanine, proline, and alanine. Our results indicated that the combination of qNMR with chemometric analysis may serve as a supplementary tool in specifying honeys.
Collapse
|