Indanedione-Zinc
Definition
A fluorescent amino acid reagent (indane-1,3-dione complexed with zinc chloride) that produces an orange-yellow fluorescent product; reported to be more sensitive than DFO on heavily aged or dilute prints.
- Reagent
- Indane-1,3-dione complexed with zinc chloride
- Target
- Amino acids in latent print residue
- Product colour
- Orange-yellow, fluorescent
- Comparison
- More sensitive than DFO on aged or dilute prints
- Substrate
- Porous surfaces, e.g. paper
Common questions
Why is fluorescence used to view indanedione-zinc developed prints instead of the visible colour?+
The zinc complex fluoresces far more strongly than it appears under white light, so examiners photograph the treated surface under a forensic light source with the correct barrier filter, which reveals faint ridge detail invisible to the naked eye.
Can indanedione-zinc be combined with other amino acid reagents on the same item?+
It is typically used as a sequential step after ninhydrin has been tried and failed, or in place of it, because both reagents react with the same amino acids and applying ninhydrin first consumes the residue the zinc formulation would otherwise develop.
Related terms
- Alpha-Amino Acids
- Molecules bearing an amine group on the carbon adjacent to the carboxyl group; the primary molecular target of ninhydrin, DFO, and indanedione...
- DFO (1,8-Diazafluoren-9-One)
- A fluorescent ninhydrin analogue used for latent fingerprint development on porous surfaces; excite at 450-470 nm (with secondary absorption extending into the...
- HFE (Hydrofluoroether)
- A class of solvents used as carriers for ninhydrin, DFO, and indanedione formulations; lower toxicity and flammability than older acetone or ethanol...
- Ninhydrin
- A chemical reagent (2,2-dihydroxyindane-1,3-dione) that reacts with alpha-amino acids in latent print residue to produce a purple-blue compound (Ruhemann's Purple); the primary...
- Physical Developer (PD)
- A multi-bath silver-deposition wet-chemistry method that deposits silver metal onto fatty latent print residue on porous surfaces; the only technique that recovers...
- Ruhemann's Purple
- The purple-blue condensation product formed when ninhydrin reacts with alpha-amino acids; the visible development indicator used in latent fingerprint examination on paper...
- Sequential Processing
- The application of chemical development methods in a fixed, evidence-preserving order that maximises cumulative recovery while preventing earlier treatments from destroying the...
- Treatment Log
- The contemporaneous written record of every chemical method applied to an item of evidence, including reagent batch, examiner identity, date/time, and result;...
- Vacuum Metal Deposition (VMD)
- A technique in which gold and zinc are sequentially evaporated in a vacuum chamber; the gold deposits uniformly while zinc nucleates differentially...