ABTS

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Chemical Name:
ABTS
Surface Used On:
Blood-stained porous & non-porous surfaces.
Sensitive To:
Blood Proteins
Development Color: Method to Record: Hazard: Protective Clothing: Fume Hood Use:

Bright Green

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
|
*** A.B.T.S. ***
|
Forensic Light
|
D.A.B.

A.B.T.S. FORMULA:
1.   (Fixative Solution)
20g 5-Sulfosalicylic Acid
dissolved in 1L distilled water


2. (Citric Acid/Phosphate Buffer)

Step A.
71.64 g Na2HPO4*12H2O
        -or-
35.61 g Na2HPO4*2H2O

Dissolved in distilled water. 
Make up to 1L in volumetric flask.
Shake vigorously to dissolve.

Step B.
21.01 g Citric acid monohydrate

Dissolved in distilled water.
Make up to 1L in volumetric flask.
Shake vigorously to dissolve.

Step C.

223 ml Na2HPO4*12H2O
  -or- Na2HPO4*2H2O
       from Step A.
177 ml Citric acid solution
       from Step B.


3.  (Working Solution)

1.25 g ABTS dissolved in 
250 ml Citric Acid/Phosphate Buffer

PROCEDURE OF APPLICATION
IMMERSION METHOD

1. 
Soak item in Fixative Solution for
3 min., then distilled water rinse.

2. (Activated Working Solution)

Using the following ratio:
 50 ml ABTS working solution
0.5 ml 27% Hydrogen peroxide

Combine and shake vigorously
in a stoppered bottle.

3.
Tray immersion of item into 
Activated Working Solution
for 5 min. Remove and rinse 
in distilled water.

4.
Allow item to air dry
under darkened lighting.
    
     -- or --
 
BLOTTING METHOD

1.
Place a dry, clean filter paper
over the region to be processed.

2.
Saturate the paper with the 
Fixative Solution using a pipette
for 3 min. Remove paper and rinse
the processed region with 
distilled water.

3.
Place another dry, clean filter paper
over the region to be processed.

4.
Vigorously shake the Activated
Working Solution. Saturate the paper
with the Activated Working Solution
using a pipette for 5 min. Remove 
paper and rinse the processed region
with distilled water.

5.
Allow item to air dry
under darkened lighting.


Ridge Detail Visualized by:

Visible chemical/stain reaction.


Reagent Applicabilities:

Porous surfaces
Non-Porous surfaces
Blood Enhancement


Other Chemical Name(s):

2,2'-azino-di-
[3-ehtylbenzthiazolinesulfonate(6)]
diammonium salt


Working Solution Shelf-life:

48 hours if refrigerated.

Process Summary:
ABTS undergoes an oxidation reaction with the heme group in hemoglobin (which acts as a catalytic site) to produce a green colored product in the presence of hydrogen peroxide. ABTS development does not interfere with DAB processing. ABTS results are equivalent to DAB on paper items. Can be used after Ninhydrin.
Accepted Deviations:
ABTS can be applied in two general manners - by immersing the item into the Activated Working Solution, or, by a "Paper Blotting" method.
Supporting Reference Materials:
1. "ABTS: A Safe Alternative to DAB for the Enhancement of Blood Fingerprints", Caldwell, J.P., Henderson, W., Kim, N.D., Jor. Forensic Sciences, Vol. 45, No. 4, July 2000, pp. 785-794.

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