The Stability of Collected Human Scent Under Various Environmental Conditions*^,†

Abstract

Human scent evidence collected from objects at a crime scene is used for scent discrimination with specially trained canines. Storage of the scent evidence is usually required yet no optimized storage protocol has been determined. Storage containers including glass, polyethylene, and aluminized pouches were evaluated to determine the optimal medium for storing human scent evidence of which glass was determined to be the optimal storage matrix. Hand odor samples were collected on three different sorbent materials, sealed in glass vials and subjected to different storage environments including room temperature, -80 degrees C conditions, dark storage, and UVA/UVB light exposure over a 7-week period. Volatile organic compounds (VOCs) in the headspace of the samples were extracted and identified using solid-phase micro-extraction-gas chromatography/mass spectrometry (SPME-GC/MS). Three-dimensional covariance mapping showed that glass containers subjected to minimal UVA/UVB light exposure provide the most stable environment for stored human scent samples.

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

“…Subjects followed the protocol for cleaning, skin cell inoculation (rubbing palms and fingers across forearms), and object manipulation as described by Hudson [13,43]. The subjects were asked to wash their hands and forearms for 30 s with Natural, Clear Olive Oil Soap from Life of the Party (North Brunswick, NJ), rinsed with water for 2 min, air dried for 4 min and then rubbed their palms, as well as their fingers, across their forearms for 5 min.…”

“…Helium was used as the carrier gas at 1 mL/min. Using the Varian MS Workstation Software, Version 6.6 (Service Pack 1), all compounds detected were verified and quantitated using an external calibration curve with standards that were purchased from Sigma Aldrich (St. Louis, MO) and recognized as human scent compounds [3,[13][14][15][16][17][18][19]37,40,43,44]. They included: octane; furfural; 2-furanmethanol; nonane; heptanal; 6-methyl-5-hepten-2-one; octanal; benzyl alcohol; (E)-2-octenal; 1-octanol; undecane; octanoic acid methyl ester; 1-nonanol; 2-decanone; dodecane; hexanedioic acid dimethyl ester; tridecane; undecanal; tetradecane; (E)-6,10-dimethyl-5,9-undecadien-2-one (geranyl acetone); pentadecane; and heptadecane.…”

Recent Advances in Solid-Phase Microextraction for Forensic Applications

“…In a forensic situation, human scent can be deposited and found at crime scenes, thus making it of special interest as trace evidence. 108 Other research topics on human scent analysis have evaluated direct and nondirect human scent collection techniques, with an emphasis on the optimization of collection materials composed of various fiber chemistries. Recent studies have taken advantage of the use of techniques such as SPME-GC-MS to analyze the headspace of collected odor samples.…”

Canine human scent identifications with post-blast debris collected from improvised explosive devices

“…Furthermore, there is a complex structure of connective tissue fibers located in the dermis, a network of blood vessels, sweat glands, oil producing glands, and hair follicles [14]. The complexity of the definition of human odor can be attributed not only to physiological causes but also to environmental factors such as scent collection procedures, dissipation/stability of human odor, contamination issues, storage protocols [15], canine training, and handler experience which ultimately direct how effective this type of trace evidence can serve in a criminal investigation [16].…”