Optimization of PIXE-sensitivity for detection of Ti in thin human skin sections

Summary, in English

Modern sunscreens contain particles like TiO2 having sizes of 25-70 nm and acting as a reflecting substance. For cosmetic reasons the particle size is minimized. Questions have been raised to what degree these nano particles penetrate the skin barrier, and how they do affect the human. The EU funded project "Quality of skin as a barrier to ultra-fine particles" - NANODERM has started with the purpose to evaluate the possible risks of TiO2 penetration into vital skin layers. The purpose of the work presented here was to find the optimal conditions for micro-PIXE analysis of Ti in thin skin sections. In the skin region where Ti is expected to be found, the naturally occurring major elements phosphorus, chlorine, sulphur and potassium have steep gradients and thus influence the X-ray background in a non-predictable manner. Based on experimental studies of Ti-exposed human skin sections using proton energies ranging from 1.8-2.55 MeV, the corresponding PIXE detection limits for Ti were calculated. The energy that was found to be the most favourable, 1.9 MeV, was then selected for future studies.

• Author: Jan Pallon; Mats Garmer; Vaida Auzelyte; Mikael Elfman; Per Kristiansson; Klas Malmqvist; Christer Nilsson; Asad Shariff; Marie Wegdén
• Department/s: Nuclear physics
• Publishing year: 2005
• Language: English
• Pages: 274-279
• Publication/Series: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms
• Volume: 231
• Issue: 1-4
• Links: http://dx.doi.org/10.1016/j.nimb.2005.01.070
• Document type: Journal article
• Publisher: Elsevier
• Topic: Subatomic Physics
• Keywords: skin; nuclear microprobe; PIXE; detection limits
• Status: Published
• Research group: Nuclear Microprobe
• ISBN/ISSN/Other: ISSN: 0168-583X