CENTENNIAL HONORS COLLEGE
Western Illinois University
Undergraduate Research Day 2015
Poster Presentation
Weathering and Storage of Forensic Soil Samples: Effects on GC-FID, Settling Rate, and
pH Characterization
Ryan Wojdyla
Faculty Mentor: Andrea Alveshere
Forensic Chemistry
Soil characterization is one of the many issues addressed using forensic chemistry techniques. In this
study, soil pH, settling rate, and gas chromatography using a flame ionization detector (GC-FID) are
examined to investigate what effects on-site weathering and soil sample storage conditions have on the
results of subsequent chemical analyses in the laboratory. Samples from several simulated “crime scene”
sites in West-Central Illinois are tested to see if soil chemistry results change over the course of several
weeks, as new aliquots are taken and tested from each individual (storage and on-site) environment. This
study assesses whether soil characterizations based upon pH, settling rate, and GC-FID data may be
substantially affected by the timing of collection or storage conditions of soil samples submitted for
comparative testing in forensic cases.