Detection of Nanoparticles in Commercial Products

Postnova Analytics reports on how the inorganic analysis team within LGC has been using the AF2000 Field Flow Fractionation system coupled to Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to characterise nanomaterials in complex sample matrices for clinical, cosmetic and food use.

Nanomaterials are known to be present in over 1300 commercial products. As the European Union (EU) recently providing a precise definition of a nanomaterial for regulatory purposes, it has become important to be able to characterise nanomaterials reliably to understand their behaviour in contact with humans and the environment.

LGC is an international life sciences measurement and testing company with a history stretching back 175 years, providing reference materials, genomics solutions and analytical testing products and services. It is home to several national government roles, including the UK National Measurement Laboratory, the Designated Institute for Chemical and Bio-measurement and the Government Chemist.

The inorganic analysis team at LGC - led by Principal Scientist and Science Fellow, Dr Heidi Goenaga-Infante - has established world class expertise in size-based and number concentration analysis of nanomaterials using hyphenated techniques to support the development of reference methods and materials, with field flow fractionation coupled to ICP-MS (FFF-ICP-MS) being the centrepiece of their multi-modal analytical approach.

Dr Goenaga-Infante commented “Over the last 15 years, Field Flow Fractionation (FFF) coupled to ICP-MS and other sizing detectors has proven itself a powerful tool for the characterisation of nanomaterials. For complex samples FFF seemed the ideal choice for matrix separation/sample fractionation, enabling us to achieve selective detection and characterisation of nanomaterials, that otherwise would have been hampered by the matrix components”.

Dr Goenaga-Infante added “Having decided that FFF was the technique for us, we approached the two leading FFF manufacturers. We selected Postnova Analytics as our vendor of choice on the basis of their fast response to queries, scientific credibility and knowledgeable technical research assistance. The Postnova AF2000 system works robustly online when coupled with ICP-MS if a systematic approach is undertaken. We very much look forward to extending this collaboration into a partnership for life.”

This project demonstrates how the FFF- ICP-MS can be used for development of a methodology to determine the number based concentration of silica nanoparticles in a complex serum sample. By itself, single particle ICP-MS failed to detect silica nanoparticles due to the high procedural blank for Si with the instrumentation available at the time. In addition, particle tracking analysis (PTA) failed to provide accurate number concentration data with a reasonable measurement uncertainty due to matrix interferences. By using flow FFF to separate the particles from the matrix with on-line PTA detection, LGC were able to accurately determine number-based concentration for silica nanoparticles of d < 100 nm in a complex biological matrix, with no requirement for chemical pre-treatment.