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Validating IND (1,2 - indanedione) (Forensic Science Communications, October 2002)

Validating IND (1,2 - indanedione) (Forensic Science Communications, October 2002)

October 2002 - Volume 4 - Number 4

Technical Note

Validating IND (1,2 - indanedione)

Stephen P. Kasper
Senior Crime Laboratory Analyst

Donna J. Minnillo
Crime Laboratory Analyst Trainee

Amy M. Rockhold
Forensic Technologist
Florida Department of Law Enforcement
Fort Myers Regional Operations Center
Fort Myers, Florida

Introduction | Materials | Safety Considerations | Formula
Procedure | Quality Control | Results | Conclusion | References


Professor Madeleine Joullié and her graduate students, Drs. Diane Hauze and Olga Petrovskaia, from the University of Pennsylvania, (Ramotowski et al. 1997) first synthesized indanediones as intermediates for preparing substituted ninhydrins for use as a fingerprint reagent. Further tests by Dr. Tony Cantu of the U.S. Secret Service (Ramotowski et al. 1997) confirmed that 1,2 - indanedione (IND) could be used as an amino acid visualizing reagent.

This study involves the use of IND for detecting latent prints on porous materials by using its ability to react with the amino acids present in body protein to produce strongly fluorescent detail when excited with green light. It was conducted as a validation of the fingerprint development process described by S. Wiesner et al. (2001), J. Almog et al. (1999), and E. Menzel (1991). This study was conducted and submitted for publication in response to the Daubert requirement that scientific processes be validated and subjected to peer review. It also serves to fulfill the Florida Department of Law Enforcement requirement that a new process first be submitted for a validation study for approval by the technical leader and chief forensic scientist before it can be used as an accepted process.


  • 1,2 - indanedione (IND)
  • ethyl acetate
  • HFE 7100
  • Scale, graduated cylinders, beakers, trays, magnetic stirrer and stirring bar, amber storage bottles
  • Forensic light source
  • Laboratory oven, photographic-mounting press

Safety Considerations

The following safety precautions were adopted:

  • Those stated in the chemical manufacturer’s literature
  • Use of forensic light source protective goggles
  • Use of fume hood
  • Use of suitable protective clothing, gloves, and goggles
  • Use of precautions to prevent contact with skin and eyes


Working Solution

2g............ 1,2 - indanedione

70ml........ ethyl acetate

930ml...... HFE 7100

Two grams of IND were dissolved in 70ml of ethyl acetate, and 930ml HFE 7100 were added to make a final volume of one liter.


1. Test specimens were prepared by placing eccrine perspiration fingerprint impressions on the various materials listed in Table 1. The same source was used for all fingerprints, and care was taken to deposit similar amounts of residue on each type of material. The specimens were prepared approximately 48 hours before processing.

2. The item to be processed was dipped, sprayed, or washed with the IND solution and allowed to dry for approximately three minutes.

3. A photographic-mounting press or laboratory oven then applied heat, although a hair dryer or dry iron could also have been used. (When the oven was used, the item was heated for 20 minutes at approximately 100º C [212º F]. When the photographic-mounting press was used, the time was two to five minutes at 100º C.)

4. If possible, a sample article was tested to determine the maximum temperature to which it could be subjected without damage. At lower temperatures, it was heated for longer periods of time, sometimes for several hours. (When using the photographic-mounting press, the evidence was placed between two pieces of craft paper because some toner materials melt and stick to the craft paper if the temperature is too high.)

5. The item was viewed under a forensic light source. Wavelengths suitable for viewing with orange goggles include 450nm, 485nm, 515nm, and 530nm. For most papers, 515nm appeared to be the optimum wavelength. Manila envelopes, brown paper bags, cardboard, and craft paper were viewed at 515nm to 570nm through an orange or red filter.

6. All prints of potential value were photographed.

Quality Control

All reagent working solutions were quality control tested at the time they were prepared. They were tested daily or before use on actual evidence and were recorded in both the reagent log and the analyst case notes. This quality control testing ensured the accuracy of the mixture and that the desired reaction was obtained.

Initial reagent formulations contained acetic acid, but it was determined that a reaction between IND and acetic acid caused a deterioration of the mixture (Wiesner et al. 2001), thus shelf life is uncertain. Elimination of the acetic acid resulted in a more stable formula and clearer fingerprints. The working solution was stored in a dark container.


Samples of various colored and textured materials were used to test the viability of IND as a fingerprint development reagent. Two specimens of each sample were prepared, one sample was heated in a 100º C oven for 20 minutes, and the other was heated in a photographic-mounting press at 100º C for two to five minutes. The samples were then examined using a Crime Scope set to 515nm and an orange barrier filter (kv55).

The processed fingerprints developed quickly and completely, particularly when heated in the photographic-mounting press. The developed fingerprints viewed under white light appeared to be more in the pink range rather than the Ruhemann’s Purple of ninhydrin. Fingerprints developed on all porous surfaces processed except the masking tape. Table 1 depicts the result of this test. Note that heating with the photographic-mounting press produced the best results.


The results of this study indicate that IND is a very sensitive amino acid reagent.

The primary benefit of IND is that, because of its fluorescent properties, the resultant developed fingerprints are clear and well-defined when illuminated with a forensic light source producing light in the 515nm range. IND worked well on a wide range of porous materials. As a result, fingerprints on dark or multicolored surfaces can be recovered through photography.

Fingerprints that had been developed by ninhydrin were further enhanced by processing with IND. Evidence known to be last touched at least one year previously was processed with IND with strong fluorescence resulting in an identification. When IND and ninhydrin are both used in processing an item, IND should be used as the primary process.


Almog, J., Bahar, E., Dayan, S., Frank, A., Khodzhaev, O., Lidor, R., Razen, S., Springer, E., Varkony, H., and Wiesner, S. Latent fingerprint visualization by IND and related compounds: Preliminary results, Journal of Forensic Sciences (1999) 44(1):114-118.

Menzel, E. R. Chemical formulations. In: An Introduction to Lasers, Forensic Lights and Fluorescent Fingerprint Detection Techniques. Lightning Powder Company, Salem, Oregon, 1991, pp. 42-44.

Ramotowski, R., Cantu, A. A., Joullié, M. M., and Petrovskaia, O. 1,2 - indanediones: A preliminary evaluation of a new class of amino acid visualizing compounds, Fingerprint Whorld (1997) 23(90): 131-140.

Wiesner, S., Almog, J., Sasson, Y., and Springer, E. Chemical development of latent fingerprints: IND has come of age, Journal of Forensic Sciences (2001) 46(5):1082-1084.