Ethyl Cyanoacrylate (ECA)
Definition
The active monomer in forensic CA fuming products and most consumer Super Glue formulations; undergoes anionic polymerisation initiated by nucleophiles (water, amines) in latent print residue.
- Role
- Active monomer in CA fuming and Super Glue
- Reaction type
- Anionic polymerisation
- Initiators
- Nucleophiles such as water and amines in print residue
- Forensic use
- Latent fingerprint development on non-porous surfaces
Common questions
Why does ethyl cyanoacrylate polymerise specifically on fingerprint residue?+
Moisture and amine compounds naturally present in sweat and skin secretions act as nucleophiles that trigger the anionic polymerisation, causing the vapor to selectively deposit and harden along the ridge detail of the print.
Is ECA the same chemical found in household super glue?+
Yes, ethyl cyanoacrylate is the primary monomer in most consumer super glue products as well as the dedicated forensic fuming formulations, though forensic products may be purified or formulated for more consistent vapor development.
Does humidity affect how well ECA fuming develops a print?+
Yes. Because atmospheric and residue moisture helps initiate the polymerisation, fuming chambers are typically run at controlled elevated humidity, and prints on very dry surfaces may develop poorly without added humidity.
Related terms
- 1:1 Macro Photography
- Photography at a reproduction ratio of 1:1 (image sensor size equals subject size); the mandatory standard for all latent fingerprint photography before...
- Alternate Light Source (ALS)
- A device emitting light at selected wavelengths (typically 415 to 535 nm) used to detect biological fluids that fluoresce or absorb light...
- Ardrox
- A commercial fluorescent dye mixture (originally for aircraft-skin crack detection) that fluoresces broadly under 365 nm UV illumination; used as a post-CA...
- Barrier Filter
- An optical long-pass filter placed over the camera lens and worn as goggles by the examiner during ALS examination; blocks the excitation...
- Basic Yellow 40 (BY40)
- A fluorescent dye (excitation 450-490 nm, emission ~530 nm) applied immediately after CA fuming with a simple aqueous rinse to remove excess;...
- Cyanoacrylate (CA) Fuming
- The development of latent prints on non-porous surfaces by exposing the item to ethyl or methyl cyanoacrylate vapour in a humidity-controlled environment;...
- Inherent Fluorescence
- The luminescent signal from latent print residue itself under ALS illumination, without any development agent; primarily from sebaceous components such as squalene...
- Lumicyano
- A proprietary Foster + Freeman formulation that combines a fluorescent CA monomer with standard CA developer, enabling simultaneous development and fluorescent marking...
- Rhodamine 6G
- A fluorescent dye applied as a post-treatment to cyanoacrylate-developed fingerprints; excited at 530 nm (green), it emits at 565-590 nm (yellow-orange), greatly...