Development of a new digital camera setup for the online recording of Schlieren optical pictures in a modified Beckman Optima XL analytical ultracentrifuge

Börger, L.; Lechner, M. D.; Stadler, Manuel

doi:10.1007/b94246

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…In the same home-made way, BASF retrofitted a preparative Beckman centrifuge with turbidity optics (Mächtle 1984; Mächtle and Börger 2006) and Schlieren optics (Börger et al 2004). Schlieren-AUC were commercial in previous times on Model-E and MOM centrifuges (discontinued), and are still the best optics for density gradients (Börger and Lechner 2006; Mächtle and Börger 2006; Mächtle and Lechner 2002).…”

Section: Methodsmentioning

confidence: 99%

Validity range of centrifuges for the regulation of nanomaterials: from classification to as-tested coronas

Wohlleben

2012

J Nanopart Res

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Granulometry is the regulatory category where the differences between traditional materials and nanomaterials culminate. Reported herein is a careful validation of methods for the quantification of dispersability and size distribution in relevant media, and for the classification according to the EC nanodefinition recommendation. Suspension-based techniques can assess the nanodefinition only if the material in question is reasonably well dispersed. Using dispersed material of several chemical compositions (organic, metal, metal-oxide) as test cases we benchmark analytical ultracentrifugation (AUC), dynamic light scattering (DLS), hydrodynamic chromatography, nanoparticle tracking analysis (NTA) against the known content of bimodal suspensions in the commercially relevant range between 20 nm and a few microns. The results validate fractionating techniques, especially AUC, which successfully identifies any dispersed nanoparticle content from 14 to 99.9 nb% with less than 5 nb% deviation. In contrast, our screening casts severe doubt over the reliability of ensemble (scattering) techniques and highlights the potential of NTA to develop into a counting upgrade of DLS. The unique asset of centrifuges with interference, X-ray or absorption detectors—to quantify the dispersed solid content for each size interval from proteins over individualized nanoparticles up to agglomerates, while accounting for their loose packing—addresses also the adsorption/depletion of proteins and (de-)agglomeration of nanomaterials under cell culture conditions as tested for toxicological endpoints.

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Section: Methodsmentioning

confidence: 99%

Validity range of centrifuges for the regulation of nanomaterials: from classification to as-tested coronas

Wohlleben

2012

J Nanopart Res

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“…A modified OPTIMA XL analytical ultracentrifuge (AUC, Beckman Coulter) was used for the static density gradient analysis. , This instrument is equipped with an eight-hole rotor and custom-built Schlieren optics with a multiplexer. The Schlieren optics setup was similar to that in a Rayleigh interferometer, but with the addition of a phase plate placed at the focal point of the condenser lens.…”

Section: Methodsmentioning

confidence: 99%

Correcting for a Density Distribution: Particle Size Analysis of Core–Shell Nanocomposite Particles Using Disk Centrifuge Photosedimentometry

et al. 2012

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Abstract. Many types of colloidal particles possess a core-shell morphology. In this paper we show that, if the core and shell densities differ, this morphology leads to an inherent density distribution for particles of finite polydispersity. If the shell is denser than the core, this density distribution implies an artificial narrowing of the particle size distribution as determined by disk centrifuge photosedimentometry (DCP). In the specific case of polystyrene/silica nanocomposite particles, which consist of a polystyrene core coated with a monolayer shell of silica nanoparticles, we demonstrate that the particle density distribution can be determined by analytical ultracentrifugation and introduce a mathematical method to account for this density distribution by reanalyzing the raw DCP data. Using the mean silica packing density calculated from small-angle xray scattering, the real particle density can be calculated for each data point. The corrected DCP particle size distribution is both broader and more consistent with particle size distributions reported for the same polystyrene/silica nanocomposite sample using other sizing techniques, such as electron microscopy, laser light diffraction and dynamic light scattering. Artifactual narrowing of the size distribution is also likely to occur for many other polymer/inorganic nanocomposite particles comprising a low-density core of variable dimensions coated with a high-density shell of constant thickness, or for core-shell latexes where the shell is continuous rather than particulate in nature.

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“…The utility and feasibility of new optical systems for AUC has been demonstrated by the user community for turbidity (Cantow 1964; Scholtan and Lange 1972; Müller 1989; Mächtle 1992, 1999a), low angle laser light scattering (Bhattacharyya 2006; Mächtle and Börger 2006), Raman scattering (Bhattacharyya 2006), the Tsvetkov optics (Lavrenko et al 1999), and Schlieren detection (Lloyd 1974; Cölfen and Borchard 1994; Mächtle 1999b; Börger et al 2004). Even though compromised by the XLI geometry, each of these optical systems provides useful, even unique ways to monitor sedimenting particles.…”

Section: Introductionmentioning

confidence: 99%

The Open AUC Project

et al. 2009

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Progress in analytical ultracentrifugation (AUC) has been hindered by obstructions to hardware innovation and by software incompatibility. In this paper, we announce and outline the Open AUC Project. The goals of the Open AUC Project are to stimulate AUC innovation by improving instrumentation, detectors, acquisition and analysis software, and collaborative tools. These improvements are needed for the next generation of AUC-based research. The Open AUC Project combines on-going work from several different groups. A new base instrument is described, one that is designed from the ground up to be an analytical ultracentrifuge. This machine offers an open architecture, hardware standards, and application programming interfaces for detector developers. All software will use the GNU Public License to assure that intellectual property is available in open source format. The Open AUC strategy facilitates collaborations, encourages sharing, and eliminates the chronic impediments that have plagued AUC innovation for the last 20 years. This ultracentrifuge will be equipped with multiple and interchangeable optical tracks so that state-of-the-art electronics and improved detectors will be available for a variety of optical systems. The instrument will be complemented by a new rotor, enhanced data acquisition and analysis software, as well as collaboration software. Described here are the instrument, the modular software components, and a standardized database that will encourage and ease integration of data analysis and interpretation software.Electronic supplementary materialThe online version of this article (doi:10.1007/s00249-009-0438-9) contains supplementary material, which is available to authorized users.

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Development of a new digital camera setup for the online recording of Schlieren optical pictures in a modified Beckman Optima XL analytical ultracentrifuge

Cited by 3 publications

References 2 publications

Validity range of centrifuges for the regulation of nanomaterials: from classification to as-tested coronas

Validity range of centrifuges for the regulation of nanomaterials: from classification to as-tested coronas

Correcting for a Density Distribution: Particle Size Analysis of Core–Shell Nanocomposite Particles Using Disk Centrifuge Photosedimentometry

The Open AUC Project

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