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|Surface Used On:
Porous surfaces, especially paper and cardboard.
Amino Acids and Proteins.
Development Complete When:
Source of Error:
(Not necessarily in this order).
Abridged Reagent Sequence
*** Ninhydrin ***
Zinc chloride / Physical Developer
FORMULA #1: Using a magnetic stirring device: 12.0 g Ninhydrin crystals dissolved in 1L alcohol solvent. FORMULA #2: Using a magnetic stirring device: 5 g ninhydrin crystals dissolve in 30 ml Methanol add - 40 ml 2-Propanol add - 930 ml Petroleum ether. - or use any - Commercial spray unit.PROCEDURE OF APPLICATION
1. a) Tray immersion of item - 5 seconds b) Brush solution onto item - until coated. c) Spray solution onto item - until coated. 2. Heat up to 80 degrees C & humidity exposure 60% - 70% relative humidity. Monitor for development, or use a steam iron. 3. Photograph the developed detail using a green colored filter. 4. View under Forensic Light Source a. 530 nm - 555 nm (no filter) b. 490 nm - 505 nm (orange filter) c. 590 nm (red filter) d. * Ninhydrin on manila file folder: 450 nm with orange filter.
Ridge Detail Visualized by:
Visible chemical/stain reaction.
Raw Wood surface
Other Chemical Name(s):
Working Solution Shelf-life:
Twelve (12) months.
Ninhydrin is an amino acid-developing reagent that is applied by dipping, brushing or spraying. Development is catalyzed by the addition of heat and atmospheric water through the use of a humidity chamber to obtain a Ruhemann's Purple dye complex. Ninhydrin may be used as a blood enhancment technique.
Several alcohols may be used as the carrier solvent. A solvent called "3M Novec Engineering Fluid HFE-7300" is promoted as a solvent which reduces background staining.
Re-immersion of the ninhydrin treated item into a tray of the blank organic solvent, then subjecting to humidity, can increase the intensity of the purple dye.
Metal salt treatments such as Zinc chloride may be used to fluoresce, and enhance, the ninhydrin developed ridge detail.
Supporting Reference Materials:|
1. "Detection of Fingerprints by the Ninhydrin Reaction", Oden, S. and von Hofsten, B., Nature, vol. 173, no. 401, 1954, pp. 449-450.
2. "Chemical Formulas and Processing Guide for Developing Latent Prints", U.S. Dept. of Justice, pg. 47-48, 1994.
3. Advances in Fingeprint Technology 2nd. Ed., Lee, H.C. & Gaensslen, R.E., CRC Press, Boca Raton, FL., 2001, pp. 177-209.
4. Manual of Fingerprint Development Techniques 2nd. Ed., Home Office - Police Scientific Development Branch, White Crescent Press, Ltd., Luton, England, 2001.
5. "Development of Latent Fingerprints and Latent Palmprints by Ninhydrin", Mooney, D.G., Identification News, Vol. 16, no. 4, 1966.
6. "Enhancement of an Insufficient Dye-Formation in the Ninhydrin Reaction by a Suitable Post Treatment Process", Rumminger, U., Nickel, U., & Geide, B., Jor. Forensic Sciences, Vol. 46, No. 2, March 2001, pp. 288-293.
7. "The Development of Latent Fingerprints With Ninhydrin", Crown, D.A., Jor. Crim. Law Criminol. Police Sci., vol. 60, no. 2, 1969, pp. 258-264.
8. Fingerprints and Other Ridge Skin Impressions, Champod, C.; Lennard, C.; Margot, P.; Stoilovic, M., CRC Press: Boca Raton, FL, 2004, pp. 114-120.
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