Novel nanoparticles containing non-stick coatings have been developed for food contact applications such as frying pans. Possible release of nanoparticles from such coatings into food is not known. In this paper, the characterisation of commercially available non-stick coatings was performed by use of FTIR, electron and optical microscopy, EDXS and XRD analysis. Characterisation revealed that the coatings contained micron- and nanosized rutile TiO particles, and quartz SiO embedded in a silicone polymer matrix. In order to estimate possible migration of TiO nanoparticles from coatings into food, migration tests into simulants (deionised water, 3% acetic acid and 5 g l citric acid) were performed (2 h at 100°C), and thermal and mechanical degradation of the matrix was studied. Simulants were analysed by ICP-MS after ultrafiltration and by microwave-assisted digestion. The concentration of titanium-containing particles that migrated into simulants was up to 861 µg l (147 µg dm). Titanium was present in simulants in ionic form as well. The presence of TiO nanoparticles in 3% acetic acid was confirmed by SEM-EDXS analysis. Thermal stability study (TG/DSC MS analysis) did not show degradation of the matrix under foreseeable conditions of use, but mechanical degradation studies (scratch and tribological testing) showed possible release (microgram quantities per punched sample) of titanium-containing nanoparticles. The matrix degradation results were confirmed by observations of the morphology of the same type of coatings actually used for food preparation. Dissolution from the surface and matrix degradation can both contribute to nanoparticles release from this type of non-stick food contact coatings.

The widespread use of titanium dioxide nanoparticles (TiO 2 NPs) in consumer products has led to an increase of their concentrations in the environment. For reliable determination of their total concentrations, the microwave assisted digestion procedure for the decomposition of nanoscale anatase and rutile was optimized and Ti concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS). To determine the TiO 2 NP concentration in environmental water samples, sample treatments, which maintain NPs dispersed and stabilized in solution, enabling quantitative transfer of TiO 2 NPs during the analytical procedure, are of crucial importance. In the present work, several dispersion approaches by the use of different mechanical and ultrasonication procedures in combination with various dispersing agents were examined in order to prepare aqueous suspensions of stable and homogeneously dispersed TiO 2 NPs. Experiments were performed with commercially available rutile and anatase NPs in MilliQ water. The efficiency of NP dispersion was evaluated by measuring the zeta potential and through the determination of the Ti concentration by ICP-MS after microwave assisted digestion of samples. Among different dispersion approaches, ultrasonication or ultrasonication in combination with dispersing agents, such as polyethyleneimine (PEI 600), ammonium polymethacrylate (Darvan C) or Triton X100, was found to be most effective for dispersing and stabilizing nanoscale rutile in MilliQ water. In order to verify the applicability of ultrasonication and its combination with dispersing agents, river and wastewater samples were spiked with nanoscale anatase and rutile and the stability of TiO 2 NP dispersions was examined by measuring the zeta potential. The results demonstrated that different environmental conditions, such as the presence of natural organic matter and ionic strength, have a significant influence on the efficiency of dispersion and the stability of TiO 2 NPs.