The Daily Bulletin Archive

Please join the Chemistry and Physics departments for the seminar "Handheld X-ray Fluorescence: Technique Improvements for Forensic Science," presented by Jefferson Sinnott, master of science degree candidate in forensic chemistry, on Thursday, October 19, from 12:15 to 1:30 p.m. in Science and Math Complex 169.

Abstract
X-ray fluorescence (XRF) spectrometry is a rapid, nondestructive, simultaneous multi-element analytical methodology for solid or liquid samples. X-ray fluorescence is an established laboratory-based method, but it is also one of the few atomic spectrometric techniques that can be used for field portable instrumentation. An opportunity for a field-portable analytical instrument would be advantageous for forensic scientists to allow processing of physical evidence without disturbing a crime scene. This presentation with discuss the basics of X-ray fluorescence spectroscopy, compare the capabilities of portable and benchtop instruments, and discuss field studies using a handheld XRF instrument.

The first case study discusses a comparison between a benchtop XRF spectrometer and a handheld XRF model. The paper examines the performance of handheld XRF instrumentation operated in air compared to a traditional benchtop XRF device that has the ability to control the analysis atmosphere. The study shows that as the measurement atmosphere affects detection levels for calcium and phosphorus, Ca/P ratios obtained from the instruments and analysis conditions were found to differ significantly. The second case study discusses a validation of a handheld XRF spectrometer for use in the field of forensic anthropology. The purpose of this research is to develop a method to distinguish human and nonhuman bones or teeth from nonbone materials of similar chemical composition. The third case study details the analysis of ochre pigments found in the city of Pompeii. Wall paintings from Pompeian houses were analyzed by means of a handheld energy dispersive X-ray fluorescence spectrometer to develop a fast method that allows chemical differentiation between red and yellow ochre. The samples were also analyzed in the laboratory with use of a benchtop energy-dispersive X-ray fluorescence spectrometer to confirm the elemental composition and the conclusions drawn from the in situ analysis.