1,2 Indanedione (IND) is a highly sensitive chemical reagent that reacts with the amino acids present in fingerprint residue. When it reacts, it creates a fluorescent compound that can be visualized under specific lighting conditions. It serves a similar function as some other popular reagents like DFO and Ninhydrin, but often produces greater sensitivity.
Equipment
- Fume Hood or Well-Ventilated Area: Working with indanedione requires proper ventilation.
- Glassware: Beakers, stirring rod, graduated cylinder.
- Spray Bottle (Optional): For applying IND solution to larger surfaces.
- Dipping Tank (Optional): For submerging items.
- Drying Chamber: A controlled environment for processed items.
- Safety Equipment: Gloves, lab coat, chemical-resistant goggles, respirator.
Ingredients for 1 Liter of 1,2 Indanedione Solution
- 1 gram 1,2 Indanedione
- 930 ml HFE-7100 (or similar fluorinated solvent)
- 60 ml Ethyl Acetate
- 10 ml Acetic Acid
Mixing Procedure
- Safety First: Don your safety equipment and work in a fume hood or ventilated area.
- Dissolve the IND: Add the 1 gram of 1,2 Indanedione to the HFE-7100 and stir until completely dissolved.
- Add Ethyl Acetate: Slowly add the ethyl acetate while stirring.
- Acetic Acid: Finally, add the acetic acid and continue stirring.
- Storage: Transfer the solution into an amber glass bottle for longer shelf-life. Label with the reagent name, date of preparation, and any hazard information.
Latent Print Processing with 1,2 Indanedione
- Pre-Treatment: Some surfaces may benefit from pre-treatment prior to IND application (consult research for your specific substrates).
- Application:
- Spraying: Apply the IND solution evenly in a fume hood.
- Dipping: Submerge the item in an IND bath in a fume hood.
- Drying: Allow the treated items to air dry in a dark, controlled drying chamber or area with good ventilation.
- Incubation: Place the dried items in a humidity chamber at around 65% relative humidity and 80°C (176°F) for 10-20 minutes.
- Visualization: Use an alternate light source (ALS) at approximately 530nm with an orange or red viewing filter to observe the fluorescent fingerprints.
- Photography: Capture detailed images of the developed prints promptly.
Storage and Shelf Life
- Light Sensitivity: Store IND working solutions in amber glass bottles to protect them from light degradation. Keep them in a cool, dark location.
- Refrigeration Recommended: Ideally, refrigerate the solution to extend its shelf life.
- Shelf Life: When stored properly, the working solution typically remains effective for approximately 6 months. However, monitor for a decline in performance over time.
Important Notes:
- 1,2 Indanedione can be followed with a post-treatment of zinc chloride to further enhance the fluorescence of developed prints.
- Always refer to your laboratories standard operating procedures (SOPs) and safety guidelines.
- Research continues into pre-treatments and other ways to improve the IND process for different substrates.