Characterization of titanium dioxide and zinc oxide nanoparticles in sunscreen powder by comparing different measurement methods

Numerous consumer products, such as cosmetics, contain nanoparticles (NPs) of titaniumdioxide (TiO2) or zinc oxide (ZnO); however, this raises questions concerning the safety ofsuch additives. Most of these products do not indicate whether the product includes NPs. Inthis study, we characterized metal oxide NPs according to size, shape, and composition aswell as their aggregation/agglomeration characteristics. In order to comprehend quicklythe characterization of metal oxide NPs, we employed single particle inductively coupledplasma (SP-ICPMS) to help quantify the size of metal oxide NPs; then, we use transmissionelectron microscopy (TEM) to corroborate the results. The crystal size and structure wasmeasured by X-ray diffraction (XRD), there are two crystal phase of TiO2 NPs in sunscreenpowder showed in XRD. However, SP-ICPMS proved highly effective in determining the sizeof NPs, the results of which remarkably good agreement with the TEM measurements. Pretreatmentincluded a conventional copper grid (requiring sample dilution) to evaluate thesize, shape and composition of primary particles or plastic embedding (without the needfor sample dilution) to evaluate the aggregate/aggregation of native NOAAs. The proposedmethod is an effective and fast approach to the characterization of oxide NPs in cosmeticsunscreen powder. These findings outline an alternative approach to the analysis of NPs inpowder-form matrix.