The Griess Test for Nitrite Ions – New Forensic Approaches

Alexey Bingor, Identification and Forensic Science, Israel Police, Jerusalem, Israel (ophirlev@gmail.com)

The Griess test is traditionally used to detect and quantify nitric oxide and nitrite ions in physiological and biological assays, as well as other types of samples that contain such compounds. Forensic scientists and examiners use this test in order to detect, and map the location and density of nitrite-originated signals on top bullet-shot targets. In this specific application, nitrite signals arise, inter alia, from organic nitro compounds that are components of the formulation of smokeless powder, an explosive that is initiated and being burned during the firing process of a firearm. The obtained nitrite density maps (chemographs) then go further interpretation. Most commonly, the amount and density of the nitrite signals is being processed and then interpreted by an examiner to be translated into shooting distance estimate (SDE), i.e., the nitrite signals are being used as a means to deduce shooting distance.

This talk will demonstrate how, in very specific cases, nitrite signals may be used for examination of shooting-related crime scenes, directly, not only for the sake of shooting distance estimation.