Performance of analytical centrifugation for the particle size analysis of real-world materials

Ullmann, Christian; Babick, Frank; Koeber, Robert

doi:10.1016/j.powtec.2017.06.057

Cited by 28 publications

(23 citation statements)

References 19 publications

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“…There are two possible light sources (470 and 865 nm) and two methods for analysis (constant time and constant position). In this study the analysis was performed by using the constant position setting, because it is recommended for the analysis of polydisperse samples with broad size distribution . The shorter wavelength is recommended for smaller particle sizes or low concentrations and the near infrared for samples with larger particles or higher concentrations.…”

Section: Resultsmentioning

confidence: 99%

“…Sizes and size distributions were obtained as extinction weighted particle size distributions by detecting the changes in transmission/extinction at a constant position . Changes in extinction over time at constant position, correspond to settled or creamed particle fractions.…”

Section: Methodsmentioning

confidence: 99%

“…The principle seems promising, not only to allow for a precise detection of the particles size, but also to detect larger particles besides a small sized main population and to discriminate between multimodal samples . The aim of this study was to investigate if an analytical centrifuge is also a suitable tool for meaningful size analysis of multimodal nanocarriers in the submicron range and if it can be used as an additional technique to classical sizing methods, for example DLS, for improved size analysis of drug nanocarriers.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Nanosized Drug Carriers by Analytical Centrifugation

Knoth

Keck

2018

Physica Status Solidi (a)

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Correct size characterization is a main prerequisite in the field of pharmaceutical nanotechnology. Different methods exist and each method possesses beneficial properties but also some drawbacks. Typical drawbacks are for example a narrow measuring range, which hampers the detection of possible larger particles or the lack to determine size distributions. Therefore, a thorough and reliable size characterization can only be performed by combining different sizing methods. Analytical centrifugation is a relatively novel technology in the field of pharmaceutics and can be used for the characterization of submicron particles. The aim of this study is to investigate if analytical centrifugation is a useful and reliable tool for size analysis of pharmaceutical nanocarriers. Different samples of known composition, that is mono-, bi-, tri-, and tetramodal samples, which are prepared from differently sized particle standards, and different drug nanocarrier systems are characterized by dynamic light scattering and by analytical centrifugation. Analytical centrifugation led to accurate size results and is found to detect all larger sized submicron particles within a small sized main population reliably, when samples with standard particles are analyzed. Size characterization of the different drug nanocarriers is not superior, when compared to classical sizing methods.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterization of Nanosized Drug Carriers by Analytical Centrifugation

Knoth

Keck

2018

Physica Status Solidi (a)

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“…The cumulative velocity distributions were always determined in a region of the transmission profiles where effects of the formed sediment on the settling velocity could be excluded. A detailed description of the applied analytic method is given in literature , . This analysis was performed at constant centrifugal force up to 2300 g .…”

Section: Methodsmentioning

confidence: 99%

Flocculant Screening Method at Lab Scale for Application in Disc Stack Centrifuges with Hermetic Design

2018

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Chemicals produced using biotechnological methods like fermentation processes are obtained as complex diluted aqueous mixture, which still contains the production organism. Centrifugation is a commonly used technology for biomass separation. By flocculation, the settling velocity of microorganisms can be increased. Here, a laboratory flocculant screening method tailored for the separation of flocculated biomass in a fully hermetic disc stack centrifuge is described. The specific requirements of this process, namely, floc formation, floc stability, sliding behavior in the disc stack, and flowability of the sludge, were transferred to lab scale and validated in pilot tests. The qualitative results of the laboratory screening were in agreement with the processes at industrial scale.

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“…Dynamic light scattering (DLS) allows sizing of particles in dispersion. But DLS very often requires high degree of dilution or is feasible for monodispersed systems only, which consequently provides misleading particle sizing analysis [43]. Small-angle or wide-angle x-ray scattering analysis is a powerful technique for characterizing inks [16,33,44], however, associated with challenging data interpretation [45] and higher operating costs.…”

Section: Introductionmentioning

confidence: 99%

On the State and Stability of Fuel Cell Catalyst Inks

Bapat

Giehl²,

Kohsakowski³

et al. 2021

Preprint

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Catalyst layers (CL) as an active component of the catalyst coated membrane (CCM) form the heart of proton electrolyte membrane fuel cells (PEMFC). For optimum performance of the fuel cell, obtaining suitable structural and functional characteristics for the CL is crucial. Direct tuning of the microstructure and morphology of the CL is non-trivial; hence catalyst inks as catalyst layer precursors need to be modulated, which are then applied onto a membrane, to form the CCM. Obtaining favorable dispersion characteristics forms an important prerequisite in engineering catalyst inks for large scale manufacturing. In order to facilitate a knowledge-based approach for developing fuel cell inks, this work introduces new tools and methods to study both the dispersion state and stability characteristics, simultaneously. Catalyst inks were prepared using different processing methods which include stirring and ultrasonication. The proposed tools are used to characterize and elucidate the effects of the processing method. Structural characterization of the dispersed particles and their assemblages was carried out by means of transmission electron microscopy. Analytical centrifugation (AC) was used to study the state and stability of inks. Herein, we introduce new concepts, S score and stability trajectory, for a time-resolved assessment of inks in their native state using AC. The findings were validated and rationalized using transmittograms as a direct visualization technique. The flowability of inks was investigated by rheological measurements. It was found that probe sonication only up to an optimum amplitude leads to a highly stable colloidal ink.

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Performance of analytical centrifugation for the particle size analysis of real-world materials

Cited by 28 publications

References 19 publications

Characterization of Nanosized Drug Carriers by Analytical Centrifugation

Characterization of Nanosized Drug Carriers by Analytical Centrifugation

Flocculant Screening Method at Lab Scale for Application in Disc Stack Centrifuges with Hermetic Design

On the State and Stability of Fuel Cell Catalyst Inks

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