DescriptionAbstract The aim of work package 2 “Sample preparation, dispersion & sampling methods” of the European project NanoDefine “Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial” is to disperse nanoparticles in such a way that the resulting dispersions of nanoparticles from substances and products are stable and contain only or mainly primary constituent particles. The issue of dispersion is particularly important in the evaluation of nanoparticle size as many potential nanomaterials are found in the form of dried powders. In order to analyze these materials with the most commonly used particle sizing instruments, it is required to convert these powders into stable liquid dispersions. The dispersion procedure is a pivotal step in the process of making measurements of the particle size distribution, so it is necessary that such procedures are effective, efficient, reproducible, and with the final product having a particle size distribution which is as close as possible to the true distribution of primary particles. An overview on the developed dispersion protocols within the NanoDefine project will be given. In large-scale scientific projects where nanomaterials need to be investigated by a number of research groups with different scientific background it is necessary to assure that all preparation and subsequent characterization procedures are as harmonized and inter-calibrated as possible. A major challenge is the dispersion of nanomaterials from powders. For this purpose standard operation procedures (SOPs) have to be developed that are feasible in most laboratories. The most common equipment present in research laboratories for efficient dispersion of nanoparticles are probe sonicators. Typical characterization techniques are dynamic light scattering and centrifugal liquid sedimentation. It has been recognized that the acoustic energies and effective de-agglomeration effects delivered by different brands of probe sonicators, and even the same brands and models, are rarely fully comparable. Moreover, small differences in the procedures such as different operators, water qualities; operation temperatures etc. may also play a role on the results. Further, the characterization methods themselves can limit the comparability of the obtained size information. An SOP will be presented which includes a calorimetric method for initial calibration of the delivered acoustic energy by adjustment of the probe-sonicator amplitude and a subsequent procedure for calibrating the effective level and quality of the dispersions. This SOP was developed in collaboration between the EU projects NanoDefine and NANoREG and based on previous work in the EU project NanoSolutions.
|Period||21 Apr 2016|
|Event title||PARTEC 2016 : International Congress on Particle Technology|