Quantitative characterization of aggregated and agglomerated titanium dioxide nanomaterials by transmission electron microscopy

Verleysen, Eveline; Temmerman, P.-J. De; Doren, Elke Van; Francisco, Michel Abi Daoud; Mast, Jan

doi:10.1016/j.powtec.2014.03.010

Cited by 22 publications

(16 citation statements)

References 27 publications

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“…TEM has been proven to be a suitable technique for providing information on structure, morphology, and chemical composition of individual particles (Adachi et al, 2010;Adachi & Buseck, 2013;Laskin et al, 2006;Li et al, 2011;Pósfai et al, 2013;Verleysen et al, 2014). However, some compounds, especially volatile species, are prone to degradation in the high vacuum conditions of the TEM (Pósfai et al, 1998;.…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

Microscopic Observations of Core‐Shell Particle Structure and Implications for Atmospheric Aerosol Remote Sensing

et al. 2018

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Although atmospheric aerosol particles can have complex heterogeneous microstructure, simplified homogeneous particle models are often used in remote sensing applications. In this study, the internal structure of individual atmospheric particles was imaged with the aim of parameterizing particle structural heterogeneity. To this end, ambient urban pollution, desert dust, and biomass burning particles were sampled in northern Europe and western Africa and analyzed by transmission electron microscopy coupled with energy dispersive X‐ray spectroscopy. Among 8,441 observed particles, about 60% of urban and 20% of desert dust particles presented residuals of coating compounds in the form of a halo surrounding a solid core. Graphic outlining of core and halo areas by image analysis revealed a dependence between halo and core dimensions as well as a greater ratio of halos thickness to total particle diameter (core plus halo) for smaller cores than for larger ones. In the case of urban pollution, the mean ratio for submicrometer and supermicrometer size fractions was 0.25 and 0.19, respectively. The corresponding mean values in the desert dust case were somewhat lower (0.22 and 0.14, respectively), but show a similar decreasing trend. Under the assumption that the halo dimension is proportional to the thickness of the particle shell, the obtained core versus shell dependencies were implemented in numerical calculations of aerosol optical characteristics. Different scenarios of the core‐shell dependencies were analyzed with respect to the influence on aerosol optical characteristics, bringing insights into sensitivity to parameterization of the core‐shell particle model in remote sensing algorithms.

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Section: Transmission Electron Microscopymentioning

confidence: 99%

Microscopic Observations of Core‐Shell Particle Structure and Implications for Atmospheric Aerosol Remote Sensing

et al. 2018

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“…Electron microscopy is a well-recognized tool for nanomaterial characterisation, recommended by the EFSA for the size measurement of nanomaterials in food ( Hardy et al, 2018 ). Transmission electron microscopy (TEM) has been proven to also be a suitable method for titanium dioxide particle analysis in a number of matrices ( Dudefoi et al, 2018 ; Geiss et al, 2019 ; Lu et al, 2018 ; Verleysen, De Temmerman, Van Doren, Abi Daoud Francisco, & Mast, 2014 ; Weir et al, 2012 ). It is currently the only analytical technique that can be expected to quantify the constituent particle size-distribution over the full size-range.…”

Section: Introductionmentioning

confidence: 99%

Particle size analysis of pristine food-grade titanium dioxide and E 171 in confectionery products: Interlaboratory testing of a single-particle inductively coupled plasma mass spectrometry screening method and confirmation with transmission electron microscopy

et al. 2021

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Titanium dioxide is a white colourant authorised as food additive E 171 in the EU, where it is used in a range of alimentary products. As these materials may contain a fraction of particulates with sizes below 100 nm and current EU regulation requires specific labelling of food ingredient to indicate the presence of engineered nanomaterials there is now a need for standardised and validated methods to appropriately size and quantify (nano)particles in food matrices. A single-particle inductively coupled plasma mass spectrometry (spICP-MS) screening method for the determination of the size distribution and concentration of titanium dioxide particles in sugar-coated confectionery and pristine food-grade titanium dioxide was developed. Special emphasis was placed on the sample preparation procedure, crucial to reproducibly disperse the particles before analysis. The transferability of this method was tested in an interlaboratory comparison study among seven experienced European food control and food research laboratories equipped with various ICP-MS instruments and using different software packages. The assessed measurands included the particle mean diameter, the most frequent diameter, the percentage of particles (in number) with a diameter below 100 nm, the particles' number concentration and a number of cumulative particle size distribution parameters (D0, D10, D50, D99.5, D99.8 and D100). The evaluated method's performance characteristics were, the within-laboratory precision, expressed as the relative repeatability standard deviation (RSDr), and the between-laboratory precision, expressed as the relative reproducibility standard deviation (RSDR). Transmission electron microscopy (TEM) was used as a confirmatory technique and served as the basis for bias estimation. The optimisation of the sample preparation step showed that when this protocol was applied to the relatively simple sample food matrices used in this study, bath sonication turned out to be sufficient to reach the highest, achievable degree of dispersed constituent particles. For the pristine material, probe sonication was required. Repeatability and reproducibility were below 10% and 25% respectively for most measurands except for the lower (D0) and the upper (D100) bound of the particle size distribution and the particle number concentration. The broader distribution of the lower and the upper bounds could be attributed to instrument-specific settings/setups (e.g. the timing parameters, the transport efficiency, type of mass-spectrometer) and software-specific data treatment algorithms. Differences in the upper bound were identified as being due to the non-harmonised application of the upper counting limit. Reporting D99.5 or D99.8 instead of the effectively largest particle diameter (D100) excluded isolated large particles and considerably improved the reproducibility. The particle number-concentration was found to be influenced by small differences in the sample preparation procedure. The comparison of these results wi...

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“…2a depicts the TEM images of synthesized reference ENMs at different magnifications. Imaging analysis indicates that the chain-like agglomerates/aggregates of ENMs consist of smaller primary particles, which is typical in FSP-synthesized nanomaterials (Teleki et al, 2008; Teoh et al, 2010; Wegner et al, 2003; Strobel et al, 2007; De Temmerman et al, 2012, 2014; Verleysen et al, 2014). In addition, the ENMs exhibit relatively narrow primary particle size distributions (see Fig.…”

Section: Resultsmentioning

confidence: 95%

Development of reference metal and metal oxide engineered nanomaterials for nanotoxicology research using high throughput and precision flame spray synthesis approaches

et al. 2018

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There is a growing need to develop and characterize reference metal and metal oxide engineered nanomaterials (ENMs) of high purity and tunable intrinsic properties suitable for nanotoxicology research. Here a high throughput (volume) and precision flame spray pyrolysis (FSP) approach coupled with state-of-the-art characterization techniques are utilized to generate such reference ENMs. The lab-based and industrially relevant FSP system, termed as Versatile Engineered Nanomaterials Generation System (VENGES), synthesizes the metals and metal oxides, at high throughput manner with controlled properties, such as primary particle size, aggregate diameter, shape, crystallinity, stoichiometry and surface chemistry. A nanopanel of nine reference ENMs (silica, silver, silver supported on silica, alumina, ceria and iron oxide) was synthesized and characterized using combined electron microscopy, advanced spectroscopic techniques and physical analyses (, BET, XRD, TEM, pycnometry, XPS, ICP-MS and FTIR). ENMs show a high degree of chemical purity and stoichiometry, and low content of carbon residuals, and are sterile and free of bacteria and endotoxins. Further, their colloidal properties and their implication in dosimetry have been also investigated in both environmental and test biological media. The suitability of reference ENMs and protocols developed in this study brings forth new arenas to generate reliable and reproducible toxicological data in an effort to reduce conflicting and contradicting inter-laboratory data on relative toxic effects of ENMs.

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Quantitative characterization of aggregated and agglomerated titanium dioxide nanomaterials by transmission electron microscopy

Cited by 22 publications

References 27 publications

Microscopic Observations of Core‐Shell Particle Structure and Implications for Atmospheric Aerosol Remote Sensing

Microscopic Observations of Core‐Shell Particle Structure and Implications for Atmospheric Aerosol Remote Sensing

Particle size analysis of pristine food-grade titanium dioxide and E 171 in confectionery products: Interlaboratory testing of a single-particle inductively coupled plasma mass spectrometry screening method and confirmation with transmission electron microscopy

Development of reference metal and metal oxide engineered nanomaterials for nanotoxicology research using high throughput and precision flame spray synthesis approaches

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