An optimal grazing-incidence position method for arsenic measurements in polyester resin skin phantoms

Arsenic (As) is a well-known toxic element. The adverse health effects of long-term As human exposure are insidious and include cancer. The exposure occurs mostly via human consumption of As contaminated well water–a naturally occurring problem in many parts of the world. The excess of As intake leads to its accumulation in keratin-rich tissues such as skin, nails, and hair. The x-ray fluorescence (XRF) method identifies elements in trace concentrations via the detection of their characteristic x-rays emitted. Portable spectrometers can be used for in vivo XRF skin As assessment in remote locations. These devices, however, were not designed for the detection of the superficially distributed As in the skin. An x-ray optics system, an x-ray detector, and a positioning stage were used to find the optimal grazing-incidence position of skin phantoms doped with As in 0, 4, 6, 8, and 12 μg/g concentrations. Using the As Kα peak height measurements, the As calibration line and a detection limit of (0.334±0.009) µg/g were obtained. The result is superior to those obtained in past studies and can guide future XRF investigations of As in skin.