Size characterisation of Au nanoparticles by ICP-MS coupling techniques

In modern nanotechnology the properties of nanoparticles (NPs) in different application fields is mainly dependent on their size and their size distribution. This paper aims to develop a reliable method for the size characterisation of Au NPs. Basing on the combination of two different separation techniques ( liquid chromatography and gel electrophoresis), coupled on-line to inductively coupled plasma-mass spectrometry (ICP-MS), we study the separation of Au NP standards. Separations by liquid chromatography show size dependent retention behaviour with good reproducibility (RSD o 1%). The results are compared with complementary methods like dynamic light scattering (DLS) and transmission electron microscopy (TEM) and show good agreement. Furthermore, the on-line coupling of gel electrophoresis and ICP-MS results in a distinct peak tailing for the analysis of these NPs, which is found to be related to the chemical structure of the NP's surface. It can be demonstrated that NPs with a covalently bound surface do behave in a different way.