MBD (7-(p-methoxybenzylamino)-4-nitrobenz-2-oxa-1,3-diazole) is a fluorescent dye. After cyanoacrylate fuming (superglue fuming), the application of MBD adds an extra level of visualization. Latent prints that have been superglued will absorb the MBD and subsequently fluoresce under a forensic light source within the 415nm to 535nm range. This provides excellent contrast, especially on multicolored or patterned surfaces where ordinary visualization techniques might be less effective.
Equipment
- Fume hood or well-ventilated area: MBD can be somewhat irritating.
- Gloves: Protect your hands from the dye.
- Protective eyewear: To prevent accidental splashes.
- Spray bottle, dipping tank, or squirt bottle: For applying the solution.
- Forensic light source: With excitation wavelengths between 415nm and 535nm.
Ingredients for 1 Liter MBD Solution
- MBD (7-(p-methoxybenzylamino)-4-nitrobenz-2-oxa-1,3-diazole): 1 gram
- Methanol: 950 ml
- HFE-7100 (or another suitable solvent): 50 ml
Mixing Procedure
- Safety First: Put on your gloves and safety glasses, and work in a fume hood or well-ventilated area.
- Dissolve the MBD: Add the MBD to the methanol and stir until it's fully dissolved.
- Add the Solvent: Slowly add in the HFE-7100 (or your chosen solvent), stirring continuously.
- Store: Transfer your mixed MBD solution to an appropriate, light-protected container.
Latent Print Processing Using MBD
- Cyanoacrylate Fuming: First, process the item with cyanoacrylate (superglue) fumes. This helps polymerize and solidify the latent print residue.
- MBD Application: Apply the MBD solution to the fumed item by spraying, dipping, or using a squirt bottle. Ensure complete coverage.
- Rinse (Optional): Some examiners rinse off excess MBD with a solvent like HFE-7100; others may allow it to air dry.
- Visualization: Examine the item under a forensic light source within the appropriate wavelength range (415nm-535nm). Developed prints will fluoresce brightly.
- Photography: Photograph any developed latent prints for documentation.
Storage and Shelf Life
- Container: Store your MBD solution in a light-protected container, as it's light-sensitive.
- Temperature: Store the solution at room temperature.
- Shelf Life: A properly mixed and stored MBD solution should have a shelf life of about six months.
Important Note: MBD and other fluorescent stains are generally applied after standard processes like cyanoacrylate fuming and should not be considered a replacement for traditional methods. Consider them as an additional tool to improve contrast and visualization of latent prints in challenging situations.