Fingerprint Development Techniques - 1,2-Diazafluoren-9-ONE (DFO)

Warning : The following procedures may require the safe handling of hazardous materials. These procedures are intended for use by trained Forensic Identification Technicians/Specialists following proper forensic laboratory health and safety protocols.

Application :
Detection of latent fingerprints on porous exhibits. DFO reacts with the amino acids to produce a light pink colored product that fluoresces yellow under blue/ green light.

Formula :

Working solution

• 0.25 grams DFO
• 30 mL methanol
• 20 mL glacial acetic acid
• 250 mL HFE71DE
• 750 mL HFE7100

1. Place 0.25 grams of DFO into a clean, dry 100 mL glass beaker
2. Measure out 30 mL of methanol and add to DFO.
3. Measure out 20 mL glacial acetic acid and add to DFO solution. Stir until DFO has completely dissolved and pour into a 2 L glass beaker.
4. Measure out 750 mL of HFE7100 and 250 mL of HFE71DE. And add both to DFO solution.
5. Store in a clean, dry, brown-glass bottle. Seal and label.

Development :

1. Pour solution into clean, dry glass, metal or plastic tray.
2. Immerse exhibit into solution until wetted.
3. Place exhibit onto absorbent paper to dry then re-immerse into solution.
4. Allow exhibit to air dry before placing in an oven set at 100 Celsius.
5. Remove exhibit after 20 minutes in oven.
6. Examine exhibit until blue and green light using the KV550 NM orange filter or the red filter respectively.

Equipment :

• glass measuring cylinders; 100 mL, 1L
• glass beaker 2L
• brown-glass bottle 1L
• magnetic stirrer plate and stirrer bar

Supplier :

• Forensi-Tech Ltd., tel: 1-613-737-5200

Bibliography :

The use of 1,8-diazafluoren-9-one (DFO) for the fluorescent detection of latent fingerprints on paper: A preliminary evaluation , Grigg, R., Mongkolaussavaratana, T., Pounds, C. A., J. Forensic Sci., 35(1), 1990, 169-174.

Improvements to the formulation of DFO and the effects of heat on the reaction with latent fingerprints , Hardwick, S., Kent, T., Sears, V. G., Winfield, P., Fingerprint Whorld, 19(73), 1993, 65-69.

Prepared by: Della Wilkinson Updated May 2003