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Hibi Y, Uesaka S, Naito M. Thermogravimetry-synchronized, reference-free quantitative mass spectrometry for accurate compositional analysis of polymer systems without prior knowledge of constituents. Analyst 2024. [PMID: 39007205 DOI: 10.1039/d4an00624k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Compositional analysis (CA)-identification and quantification of the system constituents-is the most fundamental and decisive approach for investigating the system of interest. Pyrolysis mass spectrometry (MS) with a high resolution of over 10 000 is very effective for chemical identification and is directly applicable to polymer materials regardless of their solubilities. However, it is less helpful for quantification, especially when the references, i.e., pure constituents, are unknown, non-isolable and thus cannot be prepared. To compensate for this weakness, herein we propose reference-free quantitative mass spectrometry (RQMS) with enhanced quantification accuracy assisted by synchronized thermogravimetry (TG). The key to success lies in correlating the instantaneous weight loss from TG with the MS signal, enabling the quantitative evaluation of the distinct ionization efficiency for each fragment individually. The determined ionization efficiencies allow the conversion of MS signal intensities of pyrolyzed fragments into weight abundances. In a benchmark test using ternary polymer systems, this new framework named TG-RQMS demonstrates accurate CA within ±1.3 wt% errors without using any prior knowledge or spectra of the references. This simple yet accurate and versatile CA method would be an invaluable tool to investigate polymer materials whose composition is hardly accessible via other analytical methods.
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Affiliation(s)
- Yusuke Hibi
- Data-driven Polymer Design Group, Research Center for Macromolecules and Biomaterials, National Institute for Materials Science (NIMS), 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan.
| | - Shiho Uesaka
- Data-driven Polymer Design Group, Research Center for Macromolecules and Biomaterials, National Institute for Materials Science (NIMS), 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan.
| | - Masanobu Naito
- Data-driven Polymer Design Group, Research Center for Macromolecules and Biomaterials, National Institute for Materials Science (NIMS), 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan.
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2
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Xu Y, Xie R, Li Q, Feng J, Luo H, Ye Q, Guo Z, Cao Y, Palma M, Chai G, Titirici MM, Jones CR. Pyridine Functionalized Carbon Nanotubes: Unveiling the Role of External Pyridinic Nitrogen Sites for Oxygen Reduction Reaction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2302795. [PMID: 37415517 DOI: 10.1002/smll.202302795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/20/2023] [Indexed: 07/08/2023]
Abstract
Pyridinic nitrogen has been recognized as the primary active site in nitrogen-doped carbon electrocatalysts for the oxygen reduction reaction (ORR), which is a critical process in many renewable energy devices. However, the preparation of nitrogen-doped carbon catalysts comprised of exclusively pyridinic nitrogen remains challenging, as well as understanding the precise ORR mechanisms on the catalyst. Herein, a novel process is developed using pyridyne reactive intermediates to functionalize carbon nanotubes (CNTs) exclusively with pyridine rings for ORR electrocatalysis. The relationship between the structure and ORR performance of the prepared materials is studied in combination with density functional theory calculations to probe the ORR mechanism on the catalyst. Pyridinic nitrogen can contribute to a more efficient 4-electron reaction pathway, while high level of pyridyne functionalization result in negative structural effects, such as poor electrical conductivity, reduced surface area, and small pore diameters, that suppressed the ORR performance. This study provides insights into pyridine-doped CNTs-functionalized for the first time via pyridyne intermediates-as applied in the ORR and is expected to serve as valuable inspiration in designing high-performance electrocatalysts for energy applications.
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Affiliation(s)
- Yue Xu
- Department of Chemistry, Queen Mary University of London, London, E1 4NS, UK
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Ruikuan Xie
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
| | - Qi Li
- Department of Chemistry, Queen Mary University of London, London, E1 4NS, UK
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Jingyu Feng
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Hui Luo
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Qingyu Ye
- Department of Chemistry, Queen Mary University of London, London, E1 4NS, UK
| | - Zhenyu Guo
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Ye Cao
- Department of Chemistry, Queen Mary University of London, London, E1 4NS, UK
| | - Matteo Palma
- Department of Chemistry, Queen Mary University of London, London, E1 4NS, UK
| | - Guoliang Chai
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
| | | | - Christopher R Jones
- Department of Chemistry, Queen Mary University of London, London, E1 4NS, UK
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Michalska-Domańska M, Prabucka K, Czerwiński M. Modification of Anodic Titanium Oxide Bandgap Energy by Incorporation of Tungsten, Molybdenum, and Manganese In Situ during Anodization. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2707. [PMID: 37048998 PMCID: PMC10095768 DOI: 10.3390/ma16072707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/20/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
In this research, we attempted to modify the bandgap of anodic titanium oxide by in situ incorporation of selected elements into the anodic titanium oxide during the titanium anodization process. The main aim of this research was to obtain photoactivity of anodic titanium oxide over a broader sunlight wavelength. The incorporation of the selected elements into the anodic titanium oxide was proved. It was shown that the bandgap values of anodic titanium oxides made at 60 V are in the visible region of sunlight. The smallest bandgap value was obtained for anodic titanium oxide modified by manganese, at 2.55 eV, which corresponds to a wavelength of 486.89 nm and blue color. Moreover, it was found that the pH of the electrolyte significantly affects the thickness of the anodic titanium oxide layer. The production of barrier oxides during the anodizing process with properties similar to coatings made by nitriding processes is reported for the first time.
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Dinsley JM, Davies HS, Gomez‐Gonzalez MA, Robinson CH, Pittman JK. The value of synchrotron radiation X‐ray techniques to explore microscale chemistry for ecology and evolution research. Ecosphere 2022. [DOI: 10.1002/ecs2.4312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- James M. Dinsley
- Department of Earth and Environmental Sciences The University of Manchester Manchester UK
| | - Helena S. Davies
- Department of Earth and Environmental Sciences The University of Manchester Manchester UK
| | | | - Clare H. Robinson
- Department of Earth and Environmental Sciences The University of Manchester Manchester UK
| | - Jon K. Pittman
- Department of Earth and Environmental Sciences The University of Manchester Manchester UK
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5
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Zhou L, Riegler T, Bonnetti C, McClenaghan S, Kamber B. Revisiting the Happy Jack Uraninite Reference Material: A Combined Electron Beam and Laser Ablation In Situ Study. GEOSTANDARDS AND GEOANALYTICAL RESEARCH 2022; 46:735-749. [PMID: 37067871 PMCID: PMC10091993 DOI: 10.1111/ggr.12457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 06/30/2022] [Accepted: 08/11/2022] [Indexed: 06/19/2023]
Abstract
This new comprehensive in situ mineral-chemical characterisation of the Happy Jack uraninite has discovered additional information regarding matrix effects and trace element homogeneity, relevant to proposals that it could serve as a reference material (RM). On the LA-ICP-MS instrumentation used, there was an absence of discernible matrix effects relative to the silicate glass NIST SRM 610. Lanthanides and Y are found to be very homogeneously distributed in Happy Jack uraninite, Zr, Nb and Ti mass fractions reproducible but only within individual fragments, and other elements still generally heterogeneous. This means that the Happy Jack uraninite can serve as a secondary RM for quality control in studies of natural uraninites. In terms of absolute accuracy and intermediate measurement precision, the Happy Jack uraninite can be used for the homogeneous elements. For elements that are homogeneous within individual fragments only, intermediate measurement precision can still be evaluated, while information values will be obtained for the generally heterogeneous elements. Two distinct groups (high vs. low Zr) were distinguished to exist among different Happy Jack fragments in association with minor variation of REE mass fractions, which possibly explains the observed (heavy) REE discrepancy between in situ laser ablation and bulk solution ICP-MS analyses.
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Affiliation(s)
- Lingli Zhou
- iCRAGSchool of Earth SciencesUniversity College Dublin, BelfieldDublin 4Ireland
- Geological Survey Ireland, Beggars BushDublin 4Ireland
- iCRAG, School of Natural Sciences, Department of GeologyTrinity College DublinDublin 2Ireland
| | - Thomas Riegler
- iCRAG, School of Natural Sciences, Department of GeologyTrinity College DublinDublin 2Ireland
| | - Christophe Bonnetti
- State Key Laboratory of Nuclear Resources and EnvironmentEast China University of TechnologyNanchangJiangxi330013China
| | - Sean McClenaghan
- iCRAG, School of Natural Sciences, Department of GeologyTrinity College DublinDublin 2Ireland
| | - Balz Kamber
- iCRAG, School of Natural Sciences, Department of GeologyTrinity College DublinDublin 2Ireland
- School of Earth and Atmospheric Sciences Queensland University of TechnologyBrisbaneQLD4001Australia
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6
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Gunawardana CA, Kong A, Blackwood DO, Travis Powell C, Krzyzaniak JF, Thomas MC, Calvin Sun C. Magnesium stearate surface coverage on tablets and drug crystals: Insights from SEM-EDS elemental mapping. Int J Pharm 2022; 630:122422. [PMID: 36410668 DOI: 10.1016/j.ijpharm.2022.122422] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/01/2022] [Accepted: 11/17/2022] [Indexed: 11/21/2022]
Abstract
Scanning electron microscopy-based energy dispersive X-ray spectroscopy (SEM-EDS) is proposed as a versatile tool for quantifying surface area coverage (SAC) by magnesium stearate (MgSt) on pharmaceutical tablets and particles. Our approach involved fast elemental mapping and subsequent SAC quantitation by image analysis. The study was conducted using a multi-component system, but the particle-level mapping was limited to active pharmaceutical ingredient (API) crystals. For both tablets and API particles, the calculated SAC against MgSt loading afforded a positive linear correlation over the range of MgSt levels examined in this work. On the tablet surface, MgSt was found to be preferentially concentrated at or in the close vicinity of grain boundaries, supporting the idea of compression-driven migration and relocation of MgSt within the tablet. On the particle surface, only discrete aggregates of MgSt were observed, as opposed to the widely accepted phenomenon of the formation of a thin lubricant film around host particles. The selection of proper SEM-EDS operating conditions and the challenges confronted in particle surface mapping are discussed in detail.
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Affiliation(s)
- Chamara A Gunawardana
- Pharmaceutical Materials Science and Engineering Laboratory, Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, United States
| | - Angela Kong
- Pfizer Worldwide Research and Development, Groton, CT 06340, United States
| | - Daniel O Blackwood
- Pfizer Worldwide Research and Development, Groton, CT 06340, United States
| | - C Travis Powell
- Pfizer Worldwide Research and Development, Groton, CT 06340, United States
| | | | - Myles C Thomas
- Pfizer Worldwide Research and Development, Groton, CT 06340, United States
| | - Changquan Calvin Sun
- Pharmaceutical Materials Science and Engineering Laboratory, Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, United States.
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7
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Villalobos J, Morales DM, Antipin D, Schuck G, Golnak R, Xiao J, Risch M. Stabilization of a Mn-Co Oxide During Oxygen Evolution in Alkaline Media. ChemElectroChem 2022; 9:e202200482. [PMID: 35915742 PMCID: PMC9328349 DOI: 10.1002/celc.202200482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/01/2022] [Indexed: 11/08/2022]
Abstract
Improving the stability of electrocatalysts for the oxygen evolution reaction (OER) through materials design has received less attention than improving their catalytic activity. We explored the effects of Mn addition to a cobalt oxide for stabilizing the catalyst by comparing single phase CoOx and (Co0.7Mn0.3)Ox films electrodeposited in alkaline solution. The obtained disordered films were classified as layered oxides using X-ray absorption spectroscopy (XAS). The CoOx films showed a constant decrease in the catalytic activity during cycling, confirmed by oxygen detection, while that of (Co0.7Mn0.3)Ox remained constant within error as measured by electrochemical metrics. These trends were rationalized based on XAS analysis of the metal oxidation states, which were Co2.7+ and Mn3.7+ in the bulk and similar near the surface of (Co0.7Mn0.3)Ox, before and after cycling. Thus, Mn in (Co0.7Mn0.3)Ox successfully stabilized the bulk catalyst material and its surface activity during OER cycling. The development of stabilization approaches is essential to extend the durability of OER catalysts.
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Affiliation(s)
- Javier Villalobos
- Nachwuchsgruppe Gestaltung des SauerstoffentwicklungsmechanismusHelmholtz-Zentrum Berlin für Materialien und Energie GmbHHahn-Meitner Platz 1Berlin14109Germany
| | - Dulce M. Morales
- Nachwuchsgruppe Gestaltung des SauerstoffentwicklungsmechanismusHelmholtz-Zentrum Berlin für Materialien und Energie GmbHHahn-Meitner Platz 1Berlin14109Germany
| | - Denis Antipin
- Nachwuchsgruppe Gestaltung des SauerstoffentwicklungsmechanismusHelmholtz-Zentrum Berlin für Materialien und Energie GmbHHahn-Meitner Platz 1Berlin14109Germany
| | - Götz Schuck
- Abteilung Struktur und Dynamik von EnergiematerialienHelmholtz-Zentrum Berlin für Materialien und Energie GmbHHahn-Meitner Platz 1Berlin14109Germany
| | - Ronny Golnak
- Department of Highly Sensitive X-ray SpectroscopyHelmholtz-Zentrum Berlin für Materialien und Energie GmbHAlbert-Einstein-Straße 15Berlin12489Germany
| | - Jie Xiao
- Department of Highly Sensitive X-ray SpectroscopyHelmholtz-Zentrum Berlin für Materialien und Energie GmbHAlbert-Einstein-Straße 15Berlin12489Germany
| | - Marcel Risch
- Nachwuchsgruppe Gestaltung des SauerstoffentwicklungsmechanismusHelmholtz-Zentrum Berlin für Materialien und Energie GmbHHahn-Meitner Platz 1Berlin14109Germany
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8
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Kim D, Shin SS, Jo Y, Lee SM, Ahn SK, Cho J, Yun JH, Lee HS, Park JH. Practical Enhancements in Current Density and Power Generation of Bifacial Semitransparent Ultrathin CIGSe Solar Cells via Utilization of Wide Bandgap Zn-Based Buffer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105436. [PMID: 35194961 PMCID: PMC9069376 DOI: 10.1002/advs.202105436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/13/2022] [Indexed: 06/14/2023]
Abstract
Among many building-integrated semitransparent photovoltaics (BISTPVs), semitransparent ultrathin (STUT) Cu(Inx ,Ga1-x )Se2 (CIGSe) solar cells are distinguishable due to their potential high power conversion efficiency (PCE) among other thin-film solar cells, versatile applicability based on thin film deposition processes, high stability consisting of all inorganic compositions, and practical expandability to bifacial applications. However, the fundamental trade-off relationship between PCE and transparency limits the performance of BISTPV because implementing a higher semitransparency lowers the optical budget of incoming light. To expand the available optical budget and to enhance the PCE while maintaining a suitable transparency in STUT CIGSe solar cell with single-stage coevaporated 500-nm-thick absorber, an atomic layer deposited wide bandgap Zn(O,S) buffer is introduced as the replacement of conventional CdS buffer, which partially limits incoming light less than 520 nm in wavelength. As a replacement result, more incoming light becomes valid for power conversion, and the short circuit current density (Jsc ) has increased comparatively by 17%, which has directly lead to a large increase in PCE up to 12.41%. Furthermore, Zn(O,S) buffer in the STUT CIGSe solar cell also has enhanced the bifacial compatible efficiency (BCE), which has increased to 14.44% at 1.3 sun and 19.42% at 2.0 sun.
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Affiliation(s)
- Dongryeol Kim
- Photovoltaics Research DepartmentKorea Institute of Energy Research (KIER)Daejeon34129Republic of Korea
- School of Materials Science and EngineeringKyungpook National UniversityDaegu41556Republic of Korea
| | - Sang Su Shin
- Photovoltaics Research DepartmentKorea Institute of Energy Research (KIER)Daejeon34129Republic of Korea
| | - Yonghee Jo
- Photovoltaics Research DepartmentKorea Institute of Energy Research (KIER)Daejeon34129Republic of Korea
- Department of Electrical Engineering and Smart Grid Research CenterJeonbuk National UniversityJeonju54896Republic of Korea
| | - Sang Min Lee
- Photovoltaics Research DepartmentKorea Institute of Energy Research (KIER)Daejeon34129Republic of Korea
| | - Seung Kyu Ahn
- Photovoltaics Research DepartmentKorea Institute of Energy Research (KIER)Daejeon34129Republic of Korea
| | - Jun‐Sik Cho
- Photovoltaics Research DepartmentKorea Institute of Energy Research (KIER)Daejeon34129Republic of Korea
| | - Jae Ho Yun
- Photovoltaics Research DepartmentKorea Institute of Energy Research (KIER)Daejeon34129Republic of Korea
| | - Ho Seong Lee
- School of Materials Science and EngineeringKyungpook National UniversityDaegu41556Republic of Korea
| | - Joo Hyung Park
- Photovoltaics Research DepartmentKorea Institute of Energy Research (KIER)Daejeon34129Republic of Korea
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9
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Harmon SM, Tully J, DeSantis MK, Schock MR, Triantafyllidou S, Lytle DA. A holistic approach to lead pipe scale analysis: Importance, methodology, and limitations. AWWA WATER SCIENCE 2022; 4:0. [PMID: 35586783 DOI: 10.1002/aws2.1278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
With lead service lines (LSLs) remaining for decades to come, scale analyses are critical to helping limit lead exposure from drinking water. This laboratory has used an integrated suite of analytical techniques to characterize the elemental composition, mineral identification, and physical features of scales, helping the water industry to evaluate, predict, and reduce lead corrosion. The methods used in this laboratory to prepare and analyze the LSL scale, and guidance to achieving reliable and meaningful results, are described. Primary methods include the following: optical microscopy, powder X-ray diffraction, inductively coupled plasma spectroscopy, X-ray fluorescence, scanning electron microscopy with energy dispersive spectroscopy, combustion and coulometric analyses of C and S, and X-ray absorption spectroscopy. Examples of associated pitfalls and ways to avoid them are provided, including pipe excavation/transport, sample preparation, analysis, and data interpretation. Illustrative examples are presented of practical scale analysis questions that could be answered by combinations of pipe scale analyses.
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Affiliation(s)
- Stephen M Harmon
- Office of Research and Development, Center for Environmental Solutions & Emergency Response, Water Infrastructure Division, Drinking Water Management Branch, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Jennifer Tully
- Office of Research and Development, Center for Environmental Solutions & Emergency Response, Water Infrastructure Division, Drinking Water Management Branch, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Michael K DeSantis
- Office of Research and Development, Center for Environmental Solutions & Emergency Response, Water Infrastructure Division, Drinking Water Management Branch, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Michael R Schock
- Office of Research and Development, Center for Environmental Solutions & Emergency Response, Water Infrastructure Division, Drinking Water Management Branch, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Simoni Triantafyllidou
- Office of Research and Development, Center for Environmental Solutions & Emergency Response, Water Infrastructure Division, Drinking Water Management Branch, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Darren A Lytle
- Office of Research and Development, Center for Environmental Solutions & Emergency Response, Water Infrastructure Division, Drinking Water Management Branch, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
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10
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Structural, morphological, dielectric and tensile properties of BaTiO3-doped PVA/PVP polymer blend nanocomposites. Polym Bull (Berl) 2022. [DOI: 10.1007/s00289-022-04146-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Lima AEB, Assis M, Resende ALS, Santos HLS, Mascaro LH, Longo E, Santos RS, Cavalcante LS, Luz GE. CuWO4|MnWO4 heterojunction thin film with improved photoelectrochemical and photocatalytic properties using simulated solar irradiation. J Solid State Electrochem 2022. [DOI: 10.1007/s10008-022-05143-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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12
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Kong Y, Hu H, Liu M, Hou Y, Kolivoška V, Vesztergom S, Broekmann P. Visualisation and quantification of flooding phenomena in gas diffusion electrodes used for electrochemical CO2 reduction: A combined EDX/ICP–MS approach. J Catal 2022. [DOI: 10.1016/j.jcat.2022.02.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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13
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Gupta S, Omar T, Muzzio FJ. SEM/EDX and Raman chemical imaging of pharmaceutical tablets: A comparison of tablet surface preparation and analysis methods. Int J Pharm 2022; 611:121331. [PMID: 34864123 DOI: 10.1016/j.ijpharm.2021.121331] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/11/2021] [Accepted: 11/27/2021] [Indexed: 11/29/2022]
Abstract
A better understanding of a pharmaceutical tablet's microstructure has the potential to unlock the black box between material attributes, process parameters and the critical quality attributes. Microstructure determination requires measuring the spatial-, particle size-distributions (absolute and relative) of the ingredients, and the void space, which is the overt goal of chemical Imaging (CI). Reliable quantitative results can be obtained by imaging multiple layers per tablet, with each layer having a minimal surface roughness. This study utilized scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and Raman chemical imaging (RCI) to provide a comparative discussion of results obtained when determining the microstructure of commercial zinc sulfate tablets, using three methods of tablet surface preparation: scoring & hand-fracturing, microtoming, and grating. A description of the working principles of the measurement and surface preparation methods is followed by a comparison of microstructure (particle size distribution and homogeneity of distribution) using chemical images. A comparison of the general advantages and disadvantages of SEM/EDX and RCI and the common errors in analyzing microstructure are also discussed. The results indicate that in addition to selecting the correct tablet surface preparation method, chemical imaging method, and the subsequent microstructural analyses method, correct problem formulation is also critical.
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Affiliation(s)
- Shashwat Gupta
- Chemical and Biochemical Engineering, Rutgers University, 98 Brett Road, Piscataway, NJ 08854, USA
| | - Thamer Omar
- Chemical and Biochemical Engineering, Rutgers University, 98 Brett Road, Piscataway, NJ 08854, USA
| | - Fernando J Muzzio
- Chemical and Biochemical Engineering, Rutgers University, 98 Brett Road, Piscataway, NJ 08854, USA.
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14
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Asano N, Asahina S, Lu J, Xu J, Shen Y, Qin Z, Mintova S. Advanced scanning electron microscopy techniques for structural characterization of zeolites. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00952h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chemical etching after Ar ion beam cross sectioning enables the formation of zeolite internal nano structures to be observed directly using a newly developed highly sensitive scanning electron microscope.
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Affiliation(s)
- Natsuko Asano
- JEOL Ltd, 3-1-2 Musashino, Akishima, Tokyo, 196-8558, Japan
| | | | - Jinfeng Lu
- JEOL Ltd, 3-1-2 Musashino, Akishima, Tokyo, 196-8558, Japan
| | - Jiani Xu
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Yanfeng Shen
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Zhengxing Qin
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Svetlana Mintova
- State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China
- Normandie Univ, ENSICAEN, UNICAEN, CNRS, Laboratoire Catalyse et Spectrochimie, 6 Boulevard Maréchal Juin, 14050 Caen, France
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15
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Muedi KL, Brink HG, Masindi V, Maree JP. Effective removal of arsenate from wastewater using aluminium enriched ferric oxide-hydroxide recovered from authentic acid mine drainage. JOURNAL OF HAZARDOUS MATERIALS 2021; 414:125491. [PMID: 33652214 DOI: 10.1016/j.jhazmat.2021.125491] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 02/11/2021] [Accepted: 02/21/2021] [Indexed: 06/12/2023]
Abstract
This study explored an eco-friendly approach for the synthesis of novel aluminium enriched ferric oxide-hydroxide (Fe/AlO(OH)) from authentic acid mine drainage (AMD). The synthesized Fe/AlO(OH) was subsequently tested for arsenate removal capabilities. Fe/AlO(OH) was synthesized from bona fide AMD via selective precipitation, thermal activation, and vibratory ball milling. One-factor-at-a-time (OFAAT) method was used to optimize operational parameters, which include adsorbent dosage, concentration, pH, agitation time, and temperature. Optimized conditions were observed to be 150 ppm of As(V), Solid: Liquid ratio - 1 g: 250 mL, contact time of 60 min, and ambient temperature and pH. Limited temperature and pH effects on adsorption were observed. Equilibrium data fits using Langmuir-, Freundlich-, Two surface Langmuir-, Dubinin-Radushkevich-, and Dubinin-Astokov isotherm models showed highly favorable adsorption conditions, the highest known maximum adsorption capacity for As(V) of 102-129 mg g-1, and coupled physisorption/diffusion limited adsorption. Thermodynamic analysis showed positive Gibbs free energy (ΔG°), negative enthalpy change (ΔH°), and positive entropy change (ΔS°) - likely a result of an inner sphere complexation of the As(V) with the Fe/Al surface. Considering the obtained results, valorization of AMD for the synthesis of Fe/AlO(OH) was viable and effective. This initiative could potentially minimize the footprints of AMD and arsenic pollution.
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Affiliation(s)
- K L Muedi
- Department of Chemical Engineering, Faculty of Engineering, Built Environment and Information Technology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - H G Brink
- Department of Chemical Engineering, Faculty of Engineering, Built Environment and Information Technology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
| | - V Masindi
- Department of Environmental Sciences, School of Agriculture and Environmental Sciences, University of South Africa (UNISA), P. O. Box 392, Florida 1710, South Africa
| | - J P Maree
- ROC Water Technologies, P. O. Box 70075, Die Wilgers, Pretoria 0041, South Africa
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16
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Micro-Fabric Analyzer (MFA): A New Semiautomated ArcGIS-Based Edge Detector for Quantitative Microstructural Analysis of Rock Thin-Sections. ISPRS INTERNATIONAL JOURNAL OF GEO-INFORMATION 2021. [DOI: 10.3390/ijgi10020051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Micro-Fabric Analyzer (MFA) is a new GIS-based tool for the quantitative extrapolation of rock microstructural features that takes advantage both of the characteristics of the X-ray images and the optical image features. Most of the previously developed edge mineral grain detectors are uniquely based on the physical properties of the X-ray-, electron-, or optical-derived images; not permitting the exploitation of the specific physical properties of each image type at the same time. More advanced techniques, such as 3D microtomography, permit the reconstruction of tridimensional models of mineral fabric arrays, even though adjacent mineral grain boundaries with the same atomic density are often not detectable. Only electron backscatter diffraction (EBSD) allows providing high-performing grain boundary detection that is crystallographically differentiated per mineral phase, even though it is relatively expensive and can be executed only in duly equipped microanalytical laboratories by suitably trained users. Instead, the MFA toolbox allows quantifying fabric parameters subdivided per mineral type starting from a crossed-polarizers high-resolution RGB image, which is useful for identifying the edges of the individual grains characterizing rock fabrics. Then, this image is integrated with a set of micro-X-ray maps, which are useful for the quantitative extrapolation of elemental distribution maps. In addition, all this is achieved by means of low-cost and easy-to-use equipment. We applied the tool on amphibolite, mylonitic-paragneiss, and -tonalite samples to extrapolate the particle fabric on different metamorphic rock types, as well as on the same sandstone sample used for another edge detector, which is useful for comparing the obtained results.
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17
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Brostrøm A, Kling KI, Hougaard KS, Mølhave K. Analysis of Electron Transparent Beam-Sensitive Samples Using Scanning Electron Microscopy Coupled With Energy-Dispersive X-ray Spectroscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2020; 26:373-386. [PMID: 32475372 DOI: 10.1017/s1431927620001464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy (EDS), is a powerful tool used in many scientific fields. It can provide nanoscale images, allowing size and morphology measurements, as well as provide information on the spatial distribution of elements in a sample. This study compares the capabilities of a traditional EDS detector with a recently developed annular EDS detector when analyzing electron transparent and beam-sensitive NaCl particles on a TEM grid. The optimal settings for single particle analysis are identified in order to minimize beam damage and optimize sample throughput via the choice of acceleration voltage, EDS acquisition time, and quantification model. Here, a linear combination of two models is used to bridge results for particle sizes, which are neither bulk nor sufficiently thin to assume electron transparent. Additionally, we show that the increased count rate obtainable with the annular detector enables mapping as a viable analysis strategy compared with feature detection methods, which only scan segmented regions. Finally, we discuss advantages and disadvantages of the two analysis strategies.
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Affiliation(s)
- Anders Brostrøm
- Technical University of Denmark, DTU Nanolab - National Centre for Nano Fabrication and Characterization, Fysikvej, Building 307, Kgs Lyngby2800, Denmark
- National Research Centre for the Working Environment, Lersø Parkallé 105, Copenhagen2100, Denmark
| | - Kirsten Inga Kling
- Technical University of Denmark, DTU Nanolab - National Centre for Nano Fabrication and Characterization, Fysikvej, Building 307, Kgs Lyngby2800, Denmark
- SAXOCON A/S, Bredevej 2D, Virum2830, Denmark
| | - Karin Sørig Hougaard
- National Research Centre for the Working Environment, Lersø Parkallé 105, Copenhagen2100, Denmark
| | - Kristian Mølhave
- Technical University of Denmark, DTU Nanolab - National Centre for Nano Fabrication and Characterization, Fysikvej, Building 307, Kgs Lyngby2800, Denmark
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18
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Zhong C, Lin L, Qi R, Cheng Y, Gao X, Huang R. Plan-view sample preparation of a buried nanodots array by FIB with accurate EDS positioning in thickness direction. Ultramicroscopy 2019; 207:112840. [PMID: 31505397 DOI: 10.1016/j.ultramic.2019.112840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/23/2019] [Accepted: 09/02/2019] [Indexed: 11/18/2022]
Abstract
Recently, there are growing demands on focus ion beam (FIB) sample preparation technique in plan-view geometry because it can provide the in-plane microstructure information of thin film and allows direct correlations of the atomic structure via transmission electron microscopy with micrometer-scale property measurements. However, one main technical difficulty is to position the buried thin film accurately in a sandwich structure. In this paper, an on-line positioning method based on the thickness monitoring by EDS is introduced, where the intensities of the characteristic X-ray peaks from different layers are proportional to the relative thickness of them at the same acquisition conditions. A high density array of ∼100 nm squares BiFeO3 nanodots with ∼ 25 nm thickness grown on a 20 nm thick SrRuO3 bottom electrode and (001)-oriented SrTiO3 substrate is selected for demonstration. By monitoring the intensities of Pt-M, Sr-L, Ti-K, Ru-L, Fe-K and Bi-M peaks, the relative thickness of Pt protection layer, the BiFeO3, SrRuO3 and SrTiO3 can be obtained, which provide accurate position of the BFO nanodots array in the thickness direction. With these information, the cutting parameters are optimized and a high quality plan-view specimen of BFO nanodots array is prepared, which is confirmed by high resolution transmission electron microscopy. This positioning method should have a wide application for material science.
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Affiliation(s)
- Chaorong Zhong
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, Shanghai 200062, China; School of Physics and Telecommunication Engineering, Yulin Normal University, Yulin, Guangxi 537000, China
| | - Lina Lin
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, Shanghai 200062, China
| | - Ruijuan Qi
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, Shanghai 200062, China
| | - Yan Cheng
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, Shanghai 200062, China
| | - Xingsen Gao
- Institute for Advanced Materials and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China
| | - Rong Huang
- Key Laboratory of Polar Materials and Devices (MOE) and Department of Electronics, East China Normal University, Shanghai 200062, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
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Glasscott MW, Pendergast AD, Goines S, Bishop AR, Hoang AT, Renault C, Dick JE. Electrosynthesis of high-entropy metallic glass nanoparticles for designer, multi-functional electrocatalysis. Nat Commun 2019; 10:2650. [PMID: 31201304 PMCID: PMC6570760 DOI: 10.1038/s41467-019-10303-z] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/30/2019] [Indexed: 01/24/2023] Open
Abstract
Creative approaches to the design of catalytic nanomaterials are necessary in achieving environmentally sustainable energy sources. Integrating dissimilar metals into a single nanoparticle (NP) offers a unique avenue for customizing catalytic activity and maximizing surface area. Alloys containing five or more equimolar components with a disordered, amorphous microstructure, referred to as High-Entropy Metallic Glasses (HEMGs), provide tunable catalytic performance based on the individual properties of incorporated metals. Here, we present a generalized strategy to electrosynthesize HEMG-NPs with up to eight equimolar components by confining multiple metal salt precursors to water nanodroplets emulsified in dichloroethane. Upon collision with an electrode, alloy NPs are electrodeposited into a disordered microstructure, where dissimilar metal atoms are proximally arranged. We also demonstrate precise control over metal stoichiometry by tuning the concentration of metal salt dissolved in the nanodroplet. The application of HEMG-NPs to energy conversion is highlighted with electrocatalytic water splitting on CoFeLaNiPt HEMG-NPs. High-entropy metallic glasses are an unexplored class of nanomaterials and are difficult to prepare. Here, the authors present an electrosynthetic method to design these materials with up to eight tunable metallic components and show multifunctional electrocatalytic water splitting capabilities.
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Affiliation(s)
- Matthew W Glasscott
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA
| | - Andrew D Pendergast
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA
| | - Sondrica Goines
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA
| | - Anthony R Bishop
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA
| | - Andy T Hoang
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA
| | - Christophe Renault
- Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, IP Paris, 91128, Palaiseau, France
| | - Jeffrey E Dick
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA. .,Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-3290, USA.
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20
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Gonzalez-Pech NI, Stebounova LV, Ustunol IB, Park JH, Anthony TR, Peters TM, Grassian VH. Size, composition, morphology, and health implications of airborne incidental metal-containing nanoparticles. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2019; 16:387-399. [PMID: 30570411 PMCID: PMC7086472 DOI: 10.1080/15459624.2018.1559925] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
There is great concern regarding the adverse health implications of engineered nanoparticles. However, there are many circumstances where the production of incidental nanoparticles, i.e., nanoparticles unintentionally generated as a side product of some anthropogenic process, is of even greater concern. In this study, metal-based incidental nanoparticles were measured in two occupational settings: a machining center and a foundry. On-site characterization of substrate-deposited incidental nanoparticles using a field-portable X-ray fluorescence provided some insights into the chemical characteristics of these metal-containing particles. The same substrates were then used to carry out further off-site analysis including single-particle analysis using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Between the two sites, there were similarities in the size and composition of the incidental nanoparticles as well as in the agglomeration and coagulation behavior of nanoparticles. In particular, incidental nanoparticles were identified in two forms: submicrometer fractal-like agglomerates from activities such as welding and supermicrometer particles with incidental nanoparticles coagulated to their surface, herein referenced as nanoparticle collectors. These agglomerates will affect deposition and transport inside the respiratory system of the respirable incidental nanoparticles and the corresponding health implications. The studies of incidental nanoparticles generated in occupational settings lay the groundwork on which occupational health and safety protocols should be built.
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Affiliation(s)
| | - Larissa V. Stebounova
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA
| | - Irem B. Ustunol
- Department of Nanoengineering, University of California San Diego, La Jolla, CA
| | - Jae Hong Park
- School of Health Sciences, Purdue University, West Lafayette, IN
| | - T. Renee Anthony
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA
| | - Thomas M. Peters
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA
| | - Vicki H. Grassian
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA
- Department of Nanoengineering, University of California San Diego, La Jolla, CA
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA
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21
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Dressler VL, Müller EI, Pozebon D. Bioimaging Metallomics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1055:139-181. [DOI: 10.1007/978-3-319-90143-5_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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22
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Liang C, Wang F, Fan W, Zhou W, Tong Y. Transmission electron microscopy analysis of some transition metal compounds for energy storage and conversion. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Xie M, Luo W, Gray SR. Synchrotron Fourier transform infrared mapping: A novel approach for membrane fouling characterization. WATER RESEARCH 2017; 111:375-381. [PMID: 28110141 DOI: 10.1016/j.watres.2017.01.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 06/06/2023]
Abstract
We described a synchrotron-based infrared (IR) microscopic method to characterize fouling layer induced by organic foulants and colloidal silica in membrane distillation (MD). This technique, utilizing the ultrahigh brightness of synchrotron infrared source, enables spectra with high signal-to-noise ratio that was obtained from micrometer-sized samples. Our results showed that synchrotron IR mapping was able to resolve the foulant spatial distribution in combined fouling in MD. Synchrotron IR mapping showed the spatial distribution of binary foulant (i.e., colloidal silica with alginate, bovine serum albumin (BSA) or humic acid, respectively) of the cross-section of MD membrane fouling layer. The well-resolved synchrotron IR mapping is also able to quantify the foulant distribution along the cross-section of the fouled MD membrane, providing detailed information regarding the transport and accumulation of specific foulant, which is of paramount importance to elucidate fouling mechanisms. Our results demonstrated that the synchrotron IR mapping method was a powerful method and had significant potential for both qualitative and quantitative characterization of membrane fouling layer.
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Affiliation(s)
- Ming Xie
- Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia.
| | - Wenhai Luo
- College of Resource and Environmental Science, China Agricultural University, Beijing, 100193, China
| | - Stephen R Gray
- Institute for Sustainability and Innovation, College of Engineering and Science, Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia
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Kitahara M, Kubara S, Takai A, Takimoto D, Enomoto S, Yamauchi Y, Sugimoto W, Kuroda K. Preparation of Mesoporous Bimetallic Au-Pt with a Phase-Segregated Heterostructure Using Mesoporous Silica. Chemistry 2015; 21:19142-8. [PMID: 26586355 DOI: 10.1002/chem.201503174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Indexed: 11/06/2022]
Abstract
Mesoporous bimetallic Au-Pt with a phase-segregated heterostructure has been prepared by using mesoporous silica SBA-15 as a template. Au nanoparticles were prepared as a seed metal within the mesopores, and subsequently Pt was deposited, sandwiching the Au seeds. Energy-dispersive X-ray (EDX) spectral mapping showed that the framework of mesoporous bimetallic Au-Pt, prepared by removing the silica template with HF, was composed of Au nanoparticles joined with Pt nanowires. The Au/Pt ratio of the mesoporous bimetallic Au-Pt could be varied by controlling the number of Au deposition cycles. Pre-adsorbed CO (COad) stripping voltammetry of the mesoporous bimetallic Au-Pt showed that the surfaces of the joined bimetallic structure were electrochemically active. This could be attributed to the open framework structure having a high ratio of exposed bimetallic mesopore surfaces. The described preparative approach, involving a mesoporous silica template and stepwise deposition within the mesopores, enables control of the nanostructure of the bimetallic material, which is greatly promising for the further development of synthetic methodologies for bimetallic structures.
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Affiliation(s)
- Masaki Kitahara
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199
| | - Saori Kubara
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199
| | - Azusa Takai
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199
| | - Daisuke Takimoto
- Materials and Chemical Engineering, Faculty of Textile Science and Technology, Shinshu University, Tokida-3, Ueda, Nagano 386-8567 (Japan)
| | - Shinpei Enomoto
- Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, Nishiwaseda-2, Shinjuku-ku, Tokyo 169-0051 (Japan)
| | - Yusuke Yamauchi
- World Premier International (WPI) Research Center for Materials, Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki-1, Tsukuba, Ibaraki 305-0044 (Japan)
| | - Wataru Sugimoto
- Materials and Chemical Engineering, Faculty of Textile Science and Technology, Shinshu University, Tokida-3, Ueda, Nagano 386-8567 (Japan)
| | - Kazuyuki Kuroda
- Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199. .,Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, Nishiwaseda-2, Shinjuku-ku, Tokyo 169-0051 (Japan).
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25
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Correlative micro-Raman/EPMA analysis of the hydraulic calcium silicate cement interface with dentin. Clin Oral Investig 2015; 20:1663-73. [PMID: 26556572 DOI: 10.1007/s00784-015-1650-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 11/02/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVES This study aims to characterize the chemical interplay of hydraulic calcium silicate cements at dentin. MATERIALS AND METHODS Class I cavities were prepared in non-carious human third molars and filled with Biodentine (Septodont) or ProRoot MTA (Dentsply). After 1-day, 1-week, and 1-month Dulbecco's phosphate-buffered saline (DPBS) storage, the specimens were cross-sectioned perpendicular to the cement-dentin interface. The interfaces were evaluated using micro-Raman (μRaman) spectroscopy and at a higher spatial resolution using field emission gun electron probe microanalysis (Feg-SEM/EPMA). RESULTS μRaman spectroscopy revealed the formation of a transition zone at the interface of both Biodentine (Septodont) and ProRoot MTA (Dentsply) with dentin, having an average thickness of, respectively, 7.5 ± 4.2 and 6.2 ± 5.4 μm, which however was not statistically different. No difference in interfacial ultrastructure and chemistry was found using μRaman spectroscopy between 1 day, 1 week, and 1 month DPBS-stored specimens. The observation of a transition zone at the cement-dentin interfaces contrasts with the EPMA data that revealed a sharper transition from cement to dentin. Again, no difference in interfacial ultrastructure and chemistry was found for different storage periods, with the exception of one 1 month DPBS-stored specimen prepared using Biodentine (Septodont). More specifically, EPMA revealed a gap of about 10-μm wide in the latter specimen that was filled up with newly formed calcium phosphate depositions. CONCLUSIONS Up to 1 month, the interaction of hydraulic calcium silicate cements investigated did not reveal ultrastructural or chemical changes at unaffected dentin with the exception of a calcium phosphate gap-filling property. CLINICAL RELEVANCE Hydraulic calcium silicate cements were found to fill gaps by calcium phosphate deposition, however, without conducting chemical changes to the adjacent dentin.
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26
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Liebske C. iSpectra: An Open Source Toolbox For The Analysis of Spectral Images Recorded on Scanning Electron Microscopes. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2015; 21:1006-1016. [PMID: 26165853 DOI: 10.1017/s1431927615014336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
iSpectra is an open source and system-independent toolbox for the analysis of spectral images (SIs) recorded on energy-dispersive spectroscopy (EDS) systems attached to scanning electron microscopes (SEMs). The aim of iSpectra is to assign pixels with similar spectral content to phases, accompanied by cumulative phase spectra with superior counting statistics for quantification. Pixel-to-phase assignment starts with a threshold-based pre-sorting of spectra to create groups of pixels with identical elemental budgets, similar to a method described by van Hoek (2014). Subsequent merging of groups and re-assignments of pixels using elemental or principle component histogram plots enables the user to generate chemically and texturally plausible phase maps. A variety of standard image processing algorithms can be applied to groups of pixels to optimize pixel-to-phase assignments, such as morphology operations to account for overlapping excitation volumes over pixels located at phase boundaries. iSpectra supports batch processing and allows pixel-to-phase assignments to be applied to an unlimited amount of SIs, thus enabling phase mapping of large area samples like petrographic thin sections.
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Affiliation(s)
- Christian Liebske
- Department of Earth Sciences,Institute of Geochemistry and Petrology,ETH Zürich,Sonneggstrasse 5,8092 Zürich,Switzerland
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27
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Wyroba E, Suski S, Miller K, Bartosiewicz R. Biomedical and agricultural applications of energy dispersive X-ray spectroscopy in electron microscopy. ACTA ACUST UNITED AC 2015. [DOI: 10.1515/cmble-2015-0028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractEnergy dispersive X-ray spectroscopy (EDS) in electron microscopy has been widely used in many research areas since it provides precise information on the chemical composition of subcellular structures that may be correlated with their high resolution images. In EDS the characteristic X-rays typical of each element are analyzed and the new detectors - an example of which we describe - allow for setting precisely the area of measurements and acquiring signals as a point analysis, as a linescan or in the image format of the desired area. Mapping of the elements requires stringent methods of sample preparation to prevent redistribution/loss of the elements as well as elimination of the risk of overlapping spectra. Both qualitative and quantitative analyses may be performed at a low probe current suitable for thin biological samples. Descriptions of preparation techniques, drawbacks and precautions necessary to obtain reliable results are provided, including data on standards, effects of specimen roughness and quantification. Data on EPMA application in different fields of biomedical and agricultural studies are reviewed.In this review we refer to recent EDS/EPMA applications in medical diagnostics, studies on air pollution and agrochemicals as well as on plant models used to monitor the environment.
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Burdet P, Hébert C, Cantoni M. Enhanced quantification for 3D energy dispersive spectrometry: going beyond the limitation of large volume of X-ray emission. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:1544-1555. [PMID: 24960631 DOI: 10.1017/s1431927614001688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This paper presents a method developed to quantify three-dimensional energy dispersive spectrometry (3D EDS) data with voxel size smaller than the volume from which X-rays are emitted. The influence of the neighboring voxels is corrected by applying recursively a complex quantification, improving thereby the accuracy of the quantification of critically small features. The enhanced quantification method is applied to simulated and measured data. A systematic improvement is obtained compared with classical quantification, proving the concept and the prospect of this method.
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Affiliation(s)
- Pierre Burdet
- 1Department of Materials Science and Metallurgy,University of Cambridge,Charles Babbage Road 27,Cambridge CB3 0FS,Cambridgeshire,UK
| | - Cécile Hébert
- 2Centre Interdisciplinaire de Microscopie Electronique,Ecole Polytechnique Fédérale de Lausanne (EPFL),Station 12,Lausanne 1015,Switzerland
| | - Marco Cantoni
- 2Centre Interdisciplinaire de Microscopie Electronique,Ecole Polytechnique Fédérale de Lausanne (EPFL),Station 12,Lausanne 1015,Switzerland
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Saheb N, Qadir NU, Siddiqui MU, Arif AFM, Akhtar SS, Al-Aqeeli N. Characterization of Nanoreinforcement Dispersion in Inorganic Nanocomposites: A Review. MATERIALS 2014; 7:4148-4181. [PMID: 28788670 PMCID: PMC5455911 DOI: 10.3390/ma7064148] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 11/16/2022]
Abstract
Metal and ceramic matrix composites have been developed to enhance the stiffness and strength of metals and alloys, and improve the toughness of monolithic ceramics, respectively. It is possible to further improve their properties by using nanoreinforcement, which led to the development of metal and ceramic matrix nanocomposites, in which case, the dimension of the reinforcement is on the order of nanometer, typically less than 100 nm. However, in many cases, the properties measured experimentally remain far from those estimated theoretically. This is mainly due to the fact that the properties of nanocomposites depend not only on the properties of the individual constituents, i.e., the matrix and reinforcement as well as the interface between them, but also on the extent of nanoreinforcement dispersion. Therefore, obtaining a uniform dispersion of the nanoreinforcement in the matrix remains a key issue in the development of nanocomposites with the desired properties. The issue of nanoreinforcement dispersion was not fully addressed in review papers dedicated to processing, characterization, and properties of inorganic nanocomposites. In addition, characterization of nanoparticles dispersion, reported in literature, remains largely qualitative. The objective of this review is to provide a comprehensive description of characterization techniques used to evaluate the extent of nanoreinforcement dispersion in inorganic nanocomposites and critically review published work. Moreover, methodologies and techniques used to characterize reinforcement dispersion in conventional composites, which may be used for quantitative characterization of nanoreinforcement dispersion in nanocomposites, is also presented.
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Affiliation(s)
- Nouari Saheb
- Department of Mechanical Engineering, Center of Research Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
| | - Najam Ul Qadir
- Department of Mechanical Engineering, Center of Research Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
| | - Muhammad Usama Siddiqui
- Department of Mechanical Engineering, Center of Research Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
| | - Abul Fazl Muhammad Arif
- Department of Mechanical Engineering, Center of Research Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
| | - Syed Sohail Akhtar
- Department of Mechanical Engineering, Center of Research Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
| | - Nasser Al-Aqeeli
- Department of Mechanical Engineering, Center of Research Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
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30
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Hansen TW, Wagner JB. Catalysts under Controlled Atmospheres in the Transmission Electron Microscope. ACS Catal 2014. [DOI: 10.1021/cs401148d] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Thomas W. Hansen
- Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Jakob B. Wagner
- Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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31
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Alfeld M, Wahabzada M, Bauckhage C, Kersting K, Wellenreuther G, Falkenberg G. Non-negative factor analysis supporting the interpretation of elemental distribution images acquired by XRF. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1742-6596/499/1/012013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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32
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Wuhrer R, Moran K. Quantitative X-ray mapping, scatter diagrams and the generation of correction maps to obtain more information about your material. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1757-899x/55/1/012021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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33
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Gueriau P, Mocuta C, Dutheil DB, Cohen SX, Thiaudière D, Charbonnier S, Clément G, Bertrand L. Trace elemental imaging of rare earth elements discriminates tissues at microscale in flat fossils. PLoS One 2014; 9:e86946. [PMID: 24489809 PMCID: PMC3906100 DOI: 10.1371/journal.pone.0086946] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 12/15/2013] [Indexed: 11/18/2022] Open
Abstract
The interpretation of flattened fossils remains a major challenge due to compression of their complex anatomies during fossilization, making critical anatomical features invisible or hardly discernible. Key features are often hidden under greatly preserved decay prone tissues, or an unpreparable sedimentary matrix. A method offering access to such anatomical features is of paramount interest to resolve taxonomic affinities and to study fossils after a least possible invasive preparation. Unfortunately, the widely-used X-ray micro-computed tomography, for visualizing hidden or internal structures of a broad range of fossils, is generally inapplicable to flattened specimens, due to the very high differential absorbance in distinct directions. Here we show that synchrotron X-ray fluorescence spectral raster-scanning coupled to spectral decomposition or a much faster Kullback-Leibler divergence based statistical analysis provides microscale visualization of tissues. We imaged exceptionally well-preserved fossils from the Late Cretaceous without needing any prior delicate preparation. The contrasting elemental distributions greatly improved the discrimination of skeletal elements material from both the sedimentary matrix and fossilized soft tissues. Aside content in alkaline earth elements and phosphorus, a critical parameter for tissue discrimination is the distinct amounts of rare earth elements. Local quantification of rare earths may open new avenues for fossil description but also in paleoenvironmental and taphonomical studies.
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Affiliation(s)
- Pierre Gueriau
- CR2P, UMR 7207 CNRS, MNHN, UPMC, Paris, France
- IPANEMA, USR 3461 CNRS, MCC, Gif-sur-Yvette, France
- * E-mail: (PG); (LB)
| | | | | | | | | | | | | | | | - Loïc Bertrand
- IPANEMA, USR 3461 CNRS, MCC, Gif-sur-Yvette, France
- Synchrotron SOLEIL, Gif-sur-Yvette, France
- * E-mail: (PG); (LB)
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34
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Lucas G, Burdet P, Cantoni M, Hébert C. Multivariate statistical analysis as a tool for the segmentation of 3D spectral data. Micron 2013; 52-53:49-56. [DOI: 10.1016/j.micron.2013.08.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/26/2013] [Accepted: 08/19/2013] [Indexed: 10/26/2022]
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35
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Notthoff C, Winterer M, Beckel A, Geller M, Heindl J. Spatial high resolution energy dispersive X-ray spectroscopy on thin lamellas. Ultramicroscopy 2013; 129:30-5. [DOI: 10.1016/j.ultramic.2013.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 02/01/2013] [Accepted: 02/09/2013] [Indexed: 12/01/2022]
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36
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Ault AP, Peters TM, Sawvel EJ, Casuccio GS, Willis RD, Norris GA, Grassian VH. Single-particle SEM-EDX analysis of iron-containing coarse particulate matter in an urban environment: sources and distribution of iron within Cleveland, Ohio. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:4331-4339. [PMID: 22435663 DOI: 10.1021/es204006k] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The physicochemical properties of coarse-mode, iron-containing particles and their temporal and spatial distributions are poorly understood. Single-particle analysis combining X-ray elemental mapping and computer-controlled scanning electron microscopy (CCSEM-EDX) of passively collected particles was used to investigate the physicochemical properties of iron-containing particles in Cleveland, OH, in summer 2008 (Aug-Sept), summer 2009 (July-Aug), and winter 2010 (Feb-March). The most abundant classes of iron-containing particles were iron oxide fly ash, mineral dust, NaCl-containing agglomerates (likely from road salt), and Ca-S containing agglomerates (likely from slag, a byproduct of steel production, or gypsum in road salt). The mass concentrations of anthropogenic fly ash particles were highest in the Flats region (downtown) and decreased with distance away from this region. The concentrations of fly ash in the Flats region were consistent with interannual changes in steel production. These particles were observed to be highly spherical in the Flats region, but less so after transport away from downtown. This change in morphology may be attributed to atmospheric processing. Overall, this work demonstrates that the method of passive collection with single-particle analysis by electron microscopy is a powerful tool to study spatial and temporal gradients in components of coarse particles. These gradients may correlate with human health effects associated with exposure to coarse-mode particulate matter.
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Affiliation(s)
- Andrew P Ault
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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37
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Parish CM, Brewer LN. Key parameters affecting quantitative analysis of STEM-EDS spectrum images. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2010; 16:259-272. [PMID: 20374685 DOI: 10.1017/s1431927610000267] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In this article, we use simulated and experimental data to explore how three operator-controllable parameters--(1) signal level, (2) detector resolution, and (3) number of factors chosen for analysis--affect quantitative analyses of scanning transmission electron microscopy-energy dispersive X-ray spectroscopy spectrum images processed by principal component analysis (PCA). We find that improvements in both signal level and detector resolution improve the precision of quantitative analyses, but that signal level is the most important. We also find that if the rank of the PCA solution is not chosen properly, it may be possible to improperly fit the underlying data and degrade the accuracy of results. Additionally, precision is degraded in the case when too many factors are included in the model.
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Affiliation(s)
- Chad M Parish
- Sandia National Laboratories, Albuquerque, NM 87185, USA.
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38
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Mitchell J, Chandrasekera TC, Johns ML, Gladden LF, Fordham EJ. Nuclear magnetic resonance relaxation and diffusion in the presence of internal gradients: the effect of magnetic field strength. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:026101. [PMID: 20365625 DOI: 10.1103/physreve.81.026101] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Indexed: 05/29/2023]
Abstract
It is known that internal magnetic field gradients in porous materials, caused by susceptibility differences at the solid-fluid interfaces, alter the observed effective Nuclear Magnetic Resonance transverse relaxation times T2,eff. The internal gradients scale with the strength of the static background magnetic field B0. Here, we acquire data at various magnitudes of B0 to observe the influence of internal gradients on T2-T2 exchange measurements; the theory discussed and observations made are applicable to any T2-T2 analysis of heterogeneous materials. At high magnetic field strengths, it is possible to observe diffusive exchange between regions of local internal gradient extrema within individual pores. Therefore, the observed exchange pathways are not associated with pore-to-pore exchange. Understanding the significance of internal gradients in transverse relaxation measurements is critical to interpreting these results. We present the example of water in porous sandstone rock and offer a guideline to determine whether an observed T2,eff relaxation time distribution reflects the pore size distribution for a given susceptibility contrast (magnetic field strength) and spin echo separation. More generally, we confirm that for porous materials T1 provides a better indication of the pore size distribution than T2,eff at high magnetic field strengths (B0>1 T), and demonstrate the data analysis necessary to validate pore size interpretations of T2,eff measurements.
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Affiliation(s)
- J Mitchell
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, UK.
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39
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Parish CM, Brewer LN. Multivariate statistics applications in phase analysis of STEM-EDS spectrum images. Ultramicroscopy 2010; 110:134-43. [DOI: 10.1016/j.ultramic.2009.10.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 09/28/2009] [Accepted: 10/13/2009] [Indexed: 10/20/2022]
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40
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Tanaka M, Takeguchi M, Furuya K. Wavelength dispersive X-ray spectroscopy of thick and thin samples for electron microscopes. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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41
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X-ray analysis and mapping by wavelength dispersive X-ray spectroscopy in an electron microscope. Ultramicroscopy 2008; 108:1427-31. [DOI: 10.1016/j.ultramic.2008.05.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 05/09/2008] [Indexed: 11/23/2022]
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42
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Ensslin S, Moll KP, Paulus K, Mäder K. New insight into modified release pellets - Internal structure and drug release mechanism. J Control Release 2008; 128:149-56. [PMID: 18433911 DOI: 10.1016/j.jconrel.2008.02.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 02/21/2008] [Accepted: 02/26/2008] [Indexed: 11/15/2022]
Abstract
The aim of the study was to explore the drug release mechanism from pellets, coated with blends of poly(vinyl acetate) (PVAc) and polyvinyl alcohol-polyethylene glycol graft copolymer (PVA-PEG). Water influx and drug solubilization inside the pellets were investigated in correlation to drug release. The highly soluble drug Chlorpheniramine maleate (CPM) was used as a model compound. Modified release pellets were manufactured by fluid bed drug layering and film coating of starter beads. The pellets were characterized using cross section EDX mapping, confirming location and homogeneity of the different layers. A film coat of 23%, containing PVAc/PVA-PEG in 9:1 ratio, resulted in a sigmoid shaped release curve with 2 h lag-time, followed by 3 h of continuous drug release. Using NMR analysis, water influx and drug solubilization inside the pellets were detected within 20 min. Additionally, dissolution of PVA-PEG after several minutes and drug release after the lag-time were measurable. A fast water influx into PVAc/PVA-PEG film coated pellets did not result in a fast drug release. Despite a fast drug solubilization within the pellets, drug release was initiated after 2 h, suggesting a one way stream of water during the observed lag-time.
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Affiliation(s)
- Simon Ensslin
- Technical Research & Development; Novartis Pharma AG, 4056 Basel, Switzerland
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43
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Herzing AA, Watanabe M, Edwards JK, Conte M, Tang ZR, Hutchings GJ, Kiely CJ. Energy dispersive X-ray spectroscopy of bimetallic nanoparticles in an aberration corrected scanning transmission electron microscope. Faraday Discuss 2008; 138:337-51; discussion 421-34. [DOI: 10.1039/b706293c] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Lamontagne J, Blay T, Roure I. Microbeam analysis of irradiated materials: practical aspects. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2007; 13:150-5. [PMID: 17490496 DOI: 10.1017/s143192760707033x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 02/17/2007] [Indexed: 05/15/2023]
Abstract
Among the microanalytical techniques, electron probe microanalysis (EPMA) is one of the most powerful. Its performances can be used to provide an accurate characterization. In the present article the differences between the EPMA of highly irradiated materials and standard EPMA are highlighted. It focuses on the shielded EPMA specificities. Then, the article presents the difficulties encountered during the sample preparation and the analysis (mainly due to the radioactive background). In spite of these difficulties, some valuable results can be provided by a shielded EPMA on the in-pile behavior of nuclear irradiated fuel. Some results of specific examples analyzed by EPMA in nuclear fuel research are presented.
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Affiliation(s)
- Jérôme Lamontagne
- Commissariat à l'Energie Atomique-Centre de Cadarache, DEN/DEC/SA3C/L2EC, Bât 316-13108 St Paul Lez Durance cedex, France.
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