Detection of Arsenic in Skin in vivo Using Portable X-ray Fluorescence Device (PXRF)
Arsenic is an element that is highly toxic in its inorganic form. It is widely distributed especially in water that becomes a primary source of exposure for human consumption. Chronic exposure can cause a variety of diseases such as lung cancer, bladder cancer, skin cancer, vascular diseases, and diabetes mellitus. Biomarkers for arsenic exposure are tissues that contain keratin such as hair, nails, and skin. Skin is an ideal biomarker due to its cumulative property that provides information about the individual long-term exposure to arsenic. Hence, a method for measuring arsenic levels in vivo will be useful to study the harmful effects of arsenic exposure. In this research, a portable x-ray fluorescence (XRF) device was used to determine its feasibility of detecting and quantifying arsenic in human skin. Arsenic-doped skin phantoms were used to calibrate the system. These phantoms were made using a mixture of fiberglass resin, salt solution, arsenic standard solution, and liquid hardener. In order to simulate in vivo measurement setting, lucite was used as a backing material that mimics the underlying soft tissue. The device was set at its maximum tube voltage of 50kV, 40µA, and silver filter. Each fluorescence data was measured for 180 seconds. The instrumental minimum detection limit (MDL) obtained using the phantoms alone is 0.17ppm. Meanwhile, the MDL obtained for a setup involving phantoms and lucite thickness of 4.44mm and 9.78mm are 0.21ppm and 0.23ppm respectively.
Nie, Purdue University.
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