New methodology to support the accurate quantification of nanomaterials added to food headlines Analytical Chemistry journal
Engineered nanomaterials (NM) have a variety of industrial applications with over 1300 NM-containing consumer products currently available on the market. Amongst them, nanoscale silica is one of the most highly produced and commonly used NM worldwide and can be found found in paints, coatings, electronic devices, as well as in cosmetics and in food as an anticaking agent and thickener. As a result of increasing and widespread use of NM, legislation has developed within the EU (e.g. EU Directive 1169/2011 and 1223/2009), which uses the EU recommendation for the definition of NM. This highlights the need for reliable and accurate identification and quantification of NM to support effective implementation. For nanosilica this is a particularly challenging task due to the limitations of existing methods, unpredictable behaviour of the NM in the background material (matrix) and different behaviours between dissolved and particulate silica.
Scientists within the Inorganic Analysis team at the NML have led on the development, validation and application of methodology to quantify nanoscale silica, using asymmetrical flow field-flow-fractionation (AF4) coupled to ICP-MS with size fraction-targeted isotope dilution analysis (IDA). Due to a lack of availability of materials for use as internal standards, 29Si-enriched silica nanoparticles were synthesized and characterized in-house in collaboration with HUN-REN Research Centre for Natural Sciences. Double IDA was used to quantify pristine silica particles, which showed similar physicochemical characteristics to those of the spike, and for which a well-characterised sample of natural isotopic composition to serve as calibrant, is available. For highly complex food matrices, for which well-characterised analogues of natural isotopic compositions are not available, methodology based on single IDA with AF4/ICP-MS detection was developed and validated.
This novel nanoparticle-specific methodology holds great potential for future characterisation of particle-based reference materials, including matrix-based materials. Such materials will be invaluable to support method development and validation as well as emerging legislation enforcing safe adoption and use of novel materials.
The publication which was featured on the cover of the Analytical Chemistry journal can be accessed here- Determination of the Nanoscale Silica Mass Fraction by AF4/ICP-MS with Isotope Dilution Analysis Using 29Si-Enriched Silica Nanoparticles | Analytical Chemistry (acs.org)
Bartczak, D., Cuello-Nuñez, S., Pálmai, M., Hill, S., Petrov, P., Varga, Z., Szalay, R. and Goenaga-Infante, H., 2024. Determination of the Nanoscale Silica Mass Fraction by AF4/ICP-MS with Isotope Dilution Analysis Using 29Si-Enriched Silica Nanoparticles. Analytical Chemistry.