COOMASSIE BLUE

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Chemical Name:
COOMASSIE BLUE
Surface Used On:
Blood-stained Porous & Non-porous surfaces.
Sensitive To:
Blood proteins.
Development Color: Method to Record: Hazard: Protective Clothing: Fume Hood Use:

Deep blue.

Yes
Reagent Characteristics

Development Complete When:

Source of Error:

Incompatibilities:

Precautions:

Storage Container:

Safety:

Recommendations:


Similar Reagents



Sequential Reagents
(Not necessarily in this order.)



Abridged Reagent Sequence


Visual Examination
|
Forensic Light
|
Ultra-violet light
|
*** Coomassie blue ***
|
Forensic Light

COOMASSIE BLUE FORMULA:
DYE SOLUTION:

Coomassie Blue	      4 g
Methanol	    200 ml
Distilled water	    200 ml
Glacial Acetic Acid  40 ml


RINSE SOLUTION:

Methanol	    450 ml
Distilled water	    450 ml
Glacial Acetic Acid 100 ml

PROCEDURE OF APPLICATION

1. Be certain that the blood
is 'fixed' to the surface.

2.
Squeegee bottle application -
for 30 to 90 seconds. 
A squeegee bottle is used 
to apply rinse.

3.
Tray immersion into dye solution 
30 to 90 seconds.

4.
Tray immersion into rinse solution
for 1 minute.


Ridge Detail Visualized by:

Visible chemical/stain reaction.


Reagent Applicabilities:

Porous surfaces
Non-Porous surfaces
Blood Enhancement


Other Chemical Name(s):

Coomassie Brilliant Blue
Coomassie Brilliant Blue R


Working Solution Shelf-life:

Indefinite

Process Summary:
A dye staining process, followed by a rinse procedure used to enhance detail in faint bloody impressions. "Fixing" of bloody impressions is not strictly required prior to staining. The contrast achieved with this reagent is not as strong as Amido Black due to the lighter color of the dye stain, and the development of the surfaces' background.
Accepted Deviations:
Development time may be shortened is the evidence surface strongly absorbs the dye.
Supporting Reference Materials:
1. Minutiae Magazine, Summer Special 1994, Issue No. 24, pg.7.
2. "Chemical Formulas and Processing Guide for Developing Latent Prints", U.S. Dept. of Justice, pg. 47-48, 1994.
3. Lee, H.C. & Gaensslen, R.E. (1991),"Advances in Fingerprint Technology", Elsevier, pg.86.
4. Slater, J., "Techniques for the Enhancement of 2-Dimensional Footwear Impressions in Blood", Forensic Services Div., May, 1995.
5. Navarro, R.L., "Chemical Enhancement of Questioned Footwear Impressions", North Carolina State Bureau of Inv., 1992.

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