Ralph O. Allen
Trace Analysis: Environmental, Archaeological, and Forensic Applications
Professor Allen is not currently accepting graduate students.
The development of sensitive analytical methods has helped provide more detailed information about the small chemical differences between materials which seem similar but have different histories. In some cases, like geological samples, the large scale geochemical processes can give rise to subtle yet understandable differences in those elements which are present at trace levels. We have used instrumental neutron activation analysis and X-ray fluorescence to study several types of geological materials. These materials have been investigated as part of an ongoing effort to interpret the migration of trace elements during geochemical processes. In some cases, these same geological materials have been used by prehistoric humans and hence our studies have had archaeological implications.
To provide accurate trace element data on large numbers of samples, we have investigated several other analytical methods. The inductively coupled plasma emission source used to provide ions for a quadrupole mass spectrometer (ICP-MS) holds considerable promise. This method is also being used to study soil and glass samples for applicability in the forensic laboratory. Our efforts in the forensic science field are part of a continuing cooperative effort with scientists at the FBI’s research facilities. In the past, traces of explosive residues and epoxies have been analyzed to differentiate the sources of the materials. The latest forensic science efforts have been directed toward the important new area of DNA “fingerprinting.” This major forensic tool allows small amounts of genetic material to be used to match the DNA from a suspect.
Representative Publications
Forensic determination of ricin and the alkaloid marker ricinine from castor bean extracts. Darby SM, Miller ML, Allen RO. J Forensic Sci. 6, 1033-42 (2001).
A mass spectrometric method for quantitation of intact insulin in blood samples. Darby SM, Miller ML, Allen RO, LeBeau M. J Anal Toxicol. 25, 8-14 (2001).
Analysis of two multiplexed short tandem repeat systems using capillary electrophoresis with multiwavelength fluorescence detection. Isenberg AR, Allen RO, Keys KM, Smerick JB, Budowle B, McCord BR. Electrophoresis. 19, 94-100 1998 .