title: The effect of zinc chloride, humidity and the substrate on the reaction of 1,2-indanedione-zinc with amino acids in latent fingermark secretions.
abstract: Anecdotal evidence from forensic practitioners and studies conducted under controlled conditions have indicated that the reaction between 1,2-indanedione and the amino acids present in latent fingermark deposits is highly susceptible to ambient humidity. The addition of catalytic amounts of zinc chloride to the 1,2-indanedione working solution--usually in the order of 1:25 to 1:4 molar ratio (indanedione:zinc)--significantly improves the colour and luminescence of fingermarks treated under dry conditions but appears to have a negligible effect on fingermarks treated in humid environments. The results presented in this paper confirmed that zinc(II) ions added to the 1,2-indanedione working solution act as a Lewis acid catalyst, stabilising a key intermediate during a rate-limiting hydrolysis step. Furthermore, studying the reaction using a chromatography-grade cellulose substrate method previously reported confirmed that cellulose substrates play a major role in facilitating the indanedione-amino acid reaction by acting as a surface catalyst in the early stages of the reaction and by directing the formation of the desired luminescent product (Joullié's Pink).
authors: Centre for Forensic Science, University of Technology, Sydney, Ultimo, NSW, Australia. Xanthe.Spindler@uts.edu.au
authors: Xanthe
authors: X
authors: Spindler
authors: Ronald
authors: R
authors: Shimmon
authors: Claude
authors: C
authors: Roux
authors: Chris
authors: C
authors: Lennard
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000737:chemistry*; D002712:Chlorides / Q000032:analysis / Q000737:chemistry*; D003878:Dermatoglyphics; D005554:Forensic Medicine / Q000379:methods; D006801:Humans; D006813:Humidity / Q000009:adverse effects; D007189:Indans / Q000032:analysis / Q000737:chemistry*; D007202:Indicators and Reagents / Q000737:chemistry; D008163:Luminescent Measurements; D015394:Molecular Structure; D012680:Sensitivity and Specificity; D013329:Structure-Activity Relationship; D013499:Surface Properties; D017967:Zinc Compounds / Q000032:analysis / Q000737:chemistry*
chemical_list: C413384:1,2-indanedione; D000596:Amino Acids; D002712:Chlorides; D007189:Indans; D007202:Indicators and Reagents; D017967:Zinc Compounds; C016837:zinc chloride