TEC is a fluorescent dye-stain used primarily to enhance latent fingerprints that have been treated with cyanoacrylate ester ("super glue"). Key points:
- Chelate: TEC's key ingredient is a europium chelate, a metal ion (europium) bound to organic molecules (thenoyltrifluoroacetone). This chemical structure is what gives TEC its unique fluorescent properties.
- Specificity: TEC has a strong affinity for the hardened polymers left behind by cyanoacrylate fuming.
- Fluorescence: It absorbs ultraviolet (UV) light and emits red fluorescent light, making cyanoacrylate-developed prints highly visible under the right conditions.
- Applications: TEC is particularly useful on non-porous surfaces and even on human skin (in cadaver scenarios).
Equipment
- Fume hood/well-ventilated area: Due to the solvents involved.
- Glassware: Beakers, graduated cylinders, etc.
- Protective gear: Gloves, lab coat, eye protection
- Stirring rod
- Dark containers for storage
- Spray bottle or dipping tank For application to items
- Long-wave UV light source (around 350nm) For viewing fluorescence
Ingredients for 1 Liter of TEC
- Stock Solution A:
- Thenoyltrifluoroacetone (TTA): 1 gram
- Methyl ethyl ketone (MEK): 200 mL
- Stock Solution B:
- Europium chloride hexahydrate: 0.5 grams
- Distilled water: 800 mL
Mixing Procedure
- Safety First: Work in a fume hood or ventilated area; wear proper protective gear.
- Prepare Stock Solutions:
- Solution A Dissolve TTA in MEK.
- Solution B Dissolve europium chloride hexahydrate in distilled water.
- Create Working Solution: Combine the following in order to make your final 1-liter TEC working solution:
- Stock Solution A (200 mL)
- Stock Solution B (800 mL)
- Thorough Mixing: Stir well to ensure a homogenous solution.
- Storage: Transfer to dark containers to protect from light degradation.
Latent Print Processing with TEC
- Cyanoacrylate Fuming: Treat items with cyanoacrylate to develop latent prints.
- TEC Application: Items can be either dipped in a tank of TEC solution or sprayed with TEC.
- Rinse: Gently rinse off excess TEC with distilled water.
- Dry: Allow items to air dry in a dark environment.
- Visualization: Examine items under a long-wave UV light source (~350nm) in a darkened area. Cyanoacrylate-developed prints should fluoresce bright red.
Storage and Shelf Life
- Store TEC solution in dark, airtight containers at room temperature to minimize light and oxygen exposure.
- Avoid temperature extremes.
- The shelf life of TEC solution can be around 6 months to a year, but degradation can occur. It's best to test it periodically on known fingerprint samples.
Important Notes
- TEC is a powerful tool, but it's not perfect. Success depends on factors like the cyanoacrylate application, substrate, and environmental conditions
- Always follow your laboratory's safety protocols and chemical disposal guidelines.