On the smell of Composition C-4

Area of Science:

• Analytical Chemistry
• Forensic Science
• Animal Behavior

Background:

• Explosives-detecting canines are crucial for security applications.
• The specific odor compounds triggering canine alerts for explosives like Composition C-4 (C-4) are debated.
• 2-ethyl-1-hexanol has been proposed as a key C-4 odorant for canine training.

Purpose of the Study:

• To investigate the sources of 2-ethyl-1-hexanol.
• To evaluate the efficacy of 2-ethyl-1-hexanol as a training aid for explosives detection.
• To assess canine responses to C-4 and potential odor compounds.

Main Methods:

• Gas chromatography-mass spectrometry (GC-MS) with solid-phase microextraction (SPME) was used to identify volatile compounds.
• Analysis of C-4 and various benign plastic materials.
• Canine field trials were conducted to observe detection responses.

Main Results:

• 2-ethyl-1-hexanol was detected in C-4 and also in common plasticizers and plastic items (PVC, electrical tape, credit cards).
• Canine field trials indicated no significant response from trained law enforcement dogs to 2-ethyl-1-hexanol.
• The presence of 2-ethyl-1-hexanol in non-explosive materials challenges its use as a sole indicator for C-4.

Conclusions:

• 2-ethyl-1-hexanol is not a reliable indicator for C-4 detection due to its widespread presence in common materials.
• The use of 2-ethyl-1-hexanol for training explosives-detecting canines may be discouraged.
• Further research is needed to identify the precise odor signatures of C-4 that elicit canine alerts.