title: Characterizing titanium dioxide and zinc oxide nanoparticles in sunscreen spray.
abstract: OBJECTIVE
  Numerous commercial products contain titanium dioxide (TiO2 ) and zinc oxide (ZnO) nanoparticles (NPs); however, many of these are not labelled as containing NPs. This study sought to develop an effective means of characterizing TiO2 and ZnO NPs in sunscreen sprays, including the size, shape and composition of the particles as well as their aggregation/agglomeration characteristics.
  
  
  METHODS
  Transmission electron microscopy (TEM) coupled with a window-type microchip K-kit/copper grid and X-ray diffraction (XRD) was used to characterize the oxide NPs.
  
  
  RESULTS
  TME pre-treatment was performed using two approaches: using a conventional copper grid (requiring dilution) and using a K-kit (not requiring dilution). The use of K-kit in conjunction with XRD makes it possible to obtain direct measurements from samples that have not undergone pre-treatment, which could otherwise alter the nature of the samples, such as the degree of agglomeration. XRD was used to obtain information related to particle size and crystal structure. A strong correlation was observed between XRD and TEM measurements.
  
  
  CONCLUSIONS
  The proposed measurement methods were shown to be highly effective in the characterization of oxide NPs in sunscreen sprays, providing consistent information related to NPs and their interactions in the formulations.
authors.affiliation: Food and Drug Administration, Ministry of Health and Welfare, No.161-2, Kunyang St, Nangang District, Taipei City, 115-61, Taiwan.
authors.forename: P J
authors.initials: PJ
authors.lastname: Lu
authors.affiliation: Food and Drug Administration, Ministry of Health and Welfare, No.161-2, Kunyang St, Nangang District, Taipei City, 115-61, Taiwan.
authors.forename: W L
authors.initials: WL
authors.lastname: Cheng
authors.affiliation: Food and Drug Administration, Ministry of Health and Welfare, No.161-2, Kunyang St, Nangang District, Taipei City, 115-61, Taiwan.
authors.forename: S C
authors.initials: SC
authors.lastname: Huang
authors.affiliation: Food and Drug Administration, Ministry of Health and Welfare, No.161-2, Kunyang St, Nangang District, Taipei City, 115-61, Taiwan.
authors.forename: Y P
authors.initials: YP
authors.lastname: Chen
authors.affiliation: Food and Drug Administration, Ministry of Health and Welfare, No.161-2, Kunyang St, Nangang District, Taipei City, 115-61, Taiwan.
authors.forename: H K
authors.initials: HK
authors.lastname: Chou
authors.affiliation: Food and Drug Administration, Ministry of Health and Welfare, No.161-2, Kunyang St, Nangang District, Taipei City, 115-61, Taiwan.
authors.forename: H F
authors.initials: HF
authors.lastname: Cheng
mesh_terms: D018360:Crystallography, X-Ray; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D013473:Sunscreening Agents / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D013473:Sunscreening Agents; C009495:titanium dioxide; D014025:Titanium; D015034:Zinc Oxide
keywords: chemical analysis; claim substantiation; formulation; sunscreen spray; titanium dioxide; zinc oxide