Development of a Dynamic Headspace Concentration Technique for the Non-Contact Sampling of Human Odor Samples and the Creation of Canine Training Aids

Abstract

Scent evidence is often collected by law enforcement agencies using a Scent Transfer Unit, a dynamic headspace concentration device. The goals of this research were to evaluate the STU-100 for the collection of human scent samples, and to apply this method to the collection of living and deceased human samples, and to the creation of canine training aids.The airflow rate and collection material used with the STU-100 were evaluated using a novel scent delivery method. Controlled Odor Mimic Permeation Systems were created containing representative standard compounds delivered at known rates, improving the reproducibility of optimization experiments.viii Flow rates and collection materials were compared. Higher air flow rates usually yielded significantly less total volatile compounds due to compound breakthrough through the collection material. Collection from polymer and cellulose-based materials demonstrated that the molecular backbone of the material is a factor in the trapping and releasing of compounds. The weave of the material also affects compound collection, as those materials with a tighter weave demonstrated enhanced collection efficiencies.Using the optimized method, volatiles were efficiently collected from living and deceased humans. Replicates of the living human samples showed good reproducibility; however, the odor profiles from individuals were not always distinguishable from one another. Analysis of the human remains samples revealed similarity in the type and ratio of compounds.Two types of prototype training aids were developed utilizing combinations of pure compounds as well as volatiles from actual human samples concentrated onto sorbents, which were subsequently used in field tests. The pseudo scent aids had moderate success in field tests, and the Odor pad aids had significant success. This research demonstrates that the STU-100 is a valuable tool for dog handlers and as a field instrument; however, modifications are warranted in order to improve its performance as a method for instrumental detection.

An investigation into the concurrent collection of human scent and epithelial skin cells using a non-contact sampling device

“…Nevertheless, these sampling techniques can adversely affect the collection of any other type of physical evidence in criminal investigations. Several studies have been conducted using the STU-100 for human scent collection [35][36][37][38][39][40][41]; however, to the authors' knowledge, no studies have been performed to assess its capabilities for collecting human scent and epithelial skin cells simultaneously. Thus, the purpose of this study was to evaluate the STU-100 for the concurrent collection of human scent and epithelial skin cells from porous and non-porous objects.…”

Determination of Human Scent Biomarkers for Race, Ethnicity and Gender

“…113 In addition, the grey fiber was also included for its consistent use in previous human scent research studies. 61,75,114 The three fiber chemistries were tested by using them to perform HS-SPME on the spiked samples. Duplicate extractions were performed for each fiber at three different extraction times: 1 hour, 8 hours, and 21 hours.…”

Identification of Characteristic Volatile Organic Compounds Released during the Decomposition Process of Human Remains and Analogues

“…The authors' brought to light, not only the need for standardized canine training, but also the limitations that exist in obtaining appropriate materials for HRD training. DeGreeff et al [101] developed canine training aids using a non-contact, dynamic air-flow device to sample deceased individuals. The training materials were then tested with HRD canines and a majority of the canines, close to 90%, alerted correctly, but the question still remains:…”

“…characterization of food products [114], human scent [101,[115][116][117][118][119], and the scent of death [89][90][91][120][121][122][123].…”