Filtern
Dokumenttyp
Sprache
- Englisch (4)
Schlagworte
- NanoValid (2)
- Silica nanoparticles (2)
- EU FP7 project NanoValid (1)
- Inter-laborator comparison (1)
- Inter-laboratory comparison (1)
- Nanoparticle size measurement (1)
- Nanoparticles (1)
- SEM (1)
- Surface charge (1)
- T-SEM (1)
Organisationseinheit der BAM
Potential candidates of reference nano-materials are manufactured and systematically characterized in particular with respect to their morphology (shape, size and size distribution) in the frame of the running large European project NanoValid. By exploiting the transmission operation mode in a SEM, known as T-SEM, it is demonstrated by means of three representative examples of nanoparticles how a quick morphological inspection up to a complete, metrological characterization is feasible.
The combination of complementary characterization techniques such as SEM (Scanning Electron Microscopy), T-SEM (Scanning Electron Microscopy in Transmission Mode), EDX (Energy Dispersive X-ray Spectroscopy) and SAM (Scanning Auger Microscopy) has been proven to be a powerful and relatively quick characterization strategy for comprehensive morphological and chemical characterization of individual silica and titania nanoparticles. The selected real life test materials, silica and titania, are listed in the OECD guidance manual as representative examples because they are often used as commercial nanomaterials. Imaging by high resolution SEM and in the transmission mode by T-SEM allows almost simultaneous surface and in-depth inspection of the same particle using the same instrument. EDX and SAM enable the chemical characterization of bulk and surface of individual nanoparticles. The core–shell properties of silica based materials are addressed as well. Titania nominally coated by silane purchased from an industrial source has been found to be inhomogeneous in terms of chemical composition.
An inter-laboratory comparison on the particle size, expressed as mean diameter d, of nanoscaled SiO2 (#14 BAM Silica (see NanoValid DoW, D.5.41/5.42)) has been performed. The majority of participants used Dynamic Light Scattering (DLS). A few used Electron Microscopy as method. Following methods had been applied by only one partner, respectively: Small Angle X-ray Scattering, Analytical Ultracentrifugation, Atomic Force Microscopy and Atomizer with electric mobility spectrometer.
An inter-laboratory comparison on the surface charge, expressed as zeta potential ζ, of nanoscaled SiO2 has been performed using #14 BAM Silica (see D.5.41/5.42) nanoparticles. The comparability of results delivered by participants has been tested.
The Task 5.4 of NanoValid is designed to test, compare and validate current methods to measure and characterize physicochemical properties of selected engineered nanoparticles. The measurand is Surface charge expressed as zeta-Potential. The measurements are to be accompanied by estimates of the uncertainties at a confidence level of 95%, deduced from the standard uncertainties. Therefore an uncertainty budget comprising statistical (Type A) and systematic (Type B) errors has to be established and delivered for the measurand. The protocol comprises two Annexes addressing the establishment of uncertainty budgets following GUM. The final goal of the comparison is to identify those methods of measurement which have potential as reference methods in pc characterization of nanoparticles for the determination of a given measurand.