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Specific Application Advantages

Expray and DropEx each offer advantages for specific applications.

The advantages are discussed in further detail below.


Through a series of sequential reactions, the Explosives Identification Program distinguishes between 1) polynitroaromatics, 2) nitrate esters and nitramines, and 3) inorganic nitrate compounds. This kits identifiy these classes of compounds accurately, quickly, and distinctively.


EXPRAY can be used as an investigative aid to distinguish between explosive and non-explosive material. Through two or three very simple consecutive tests the kit will provide visual evidence of traces of the explosives listed below. The traces can be found on any surface suspected to have been in contact with explosives.


What does each reagent test for? 

Expray/DropEx-1 - Group A (Nitroaromatics) - This type of explosive includes TNT, Tetryl, TNB, DNT, picric acid and its salts.


Expray/DropEx-2 - Group B (Nitrate esters and nitramines) - This type of explosive includes Dynamite, Nitroglycerine, RDX, PETN, Semtex, Nitrocellulose, smokeless powder, and Tetryl. NOTE: Most plastic-type of explosives belong to this group.


Expray/DropEx-3 - Group I (Inorganic nitrates) - The nitrates based explosives include ANFO (ammonium nitrate-fuel oil), commercial and improvised explosives based on inorganic nitrates, black powder, flash powder, potassium nitrate, and ammonium nitrate.


DropEx-A - Chlorates (such as potassium chlorate and sodium chlorate) and bromates. Often used in improvised explosive devices.


DropEx B – Peroxide-based explosives, which are being used by terrorists with increasing frequency. One of the more dangerous peroxide based compounds is triacetonetriperoxide (TATP). Also detects hexamethylenetriperoxidediamine (HMTD).


How do I decide if I should use EXPRAY or DropEx?


Each of the kits fills a particular niche. Descriptions of the most significant differences are presented below.


Sensitivity - The sensitivity of the kits has to do with the ratio of the amount of reagent to the amount of the target compound. The spray products deliver a smaller amount of reagent and are therefore typically more sensitive. However, the greater sensitivity is not always desirable. For example if the test is being used to evaluate explosive hazard of metal scrap, Expray may be too sensitive.


Shelf life - Both products are warranted for 12 months from receipt. Expray packaging is such that it can be used all at once or throughout that year. DropEx 1 must be used within 30 days of breaking to seal on the packaging.


Propellants – Large caliber gun propellant grains incorporate a significant amount of plasticizer and the energetic material may not be exposed on the surface. DropEx is very effective in breaking the coating and exposing the energetic material. Expray sometimes requires that the surface be pretreated with a drop of solvent.


Shipping – DropEx contains only a limited quantity of flammable liquid and can be shipped or carried without any special marking or handling requirements. Thus, it can be shipped easily via air and into areas of conflict with normal freight. Expray ships as a dangerous good and requires special labeling and handling in transit. This special handling carries an increased cost and extends shipping time to areas of conflict.




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