Detecting the presence of nanoparticles in consumer products is an enduring challenge for analytical laboratories.
Although many different techniques can potentially be used to measure the dimension of objects smaller than a 1/10000 of a millimetre, in practice, the results obtained using different methods may not always prove to be consistent.
Amongst the many types of nanomaterials which are finding applications in consumer products, those based on silver nanoparticles (AgNPs) constitute one of the largest and fastest growing categories. In particular, their powerful antimicrobial properties and relatively low cost have led to silver nanoparticles being proposed for used in a number of applications including food contact materials, cosmetics, wall paints, textiles, laundry detergents, biocide sprays and medical devices.
In a recent research paper JRC scientists have described studies carried out at their premises, showing how silver nanoparticles can be detected in real-world liquid antimicrobial consumer products. The presence of nanoparticles (based on the challenging EU definition of nanomaterial) was confirmed using different techniques such as Centrifugal Liquid Sedimentation, Transmission Electron Microscopy, and Asymmetric Flow Field Flow Fractionation-Inductively Coupled Plasma Mass Spectrometry. In particular, with this last method it was possible to show how the experimentally determined mass-size based distribution could be converted to a number-based distribution, as required by the EC definition. This technique, despite the possibility of experimental artefacts being mathematically amplified in conversion, showed promising results when compared to the number-size distributions determined by the much more complex and expensive electron-microscopy based methods.
The methodologies described in this work could, with further development, potentially find applications in the implementation of the EU nanomaterial definition in areas such as product labelling.
Read more in the article Detection, quantification and derivation of number size distribution of silver nanoparticles in antimicrobial consumer products, Cascio C., Geiss O., Franchini F., Ojea-Jimenez I., Rossi F., Gilliland D. and Calzolai L., Journal of Analytical Atomic Spectrometry, 2015, 30,1255-1265.