TY - JOUR
T1 - The Effect of Zinc Chloride, Humidity and the Substrate on the Reaction of 1,2-Indanedione-Zinc with Amino Acids in Latent Fingermark Secretions
AU - Spindler, Xanthe
AU - Shimmon, Ronald
AU - Roux, Claude
AU - Lennard, Christopher
PY - 2011
Y1 - 2011
N2 - 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)
AB - 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)
U2 - 10.1016/j.forsciint.2011.06.005
DO - 10.1016/j.forsciint.2011.06.005
M3 - Article
SN - 0379-0738
VL - 212
SP - 150
EP - 157
JO - Forensic Science International
JF - Forensic Science International
IS - 1-3
ER -