Forensic Fact of the Day - Rhodizonate Test (Lead)

The RHODIZONATE TEST is a colour test for lead (Pb) particulates expelled from the muzzle of a firearm and found embedded in, or deposited on, the skin of a victim, the surface of a target, or the hands of the shooter. The test involves spraying the forensic exhibit with a weak aqueous solution of sodium rhodizonate (which has a dark yellowish/orange colour). The reagent reacts with any lead (Pb0) and lead (Pb2+) salts turning bright scarlet or purple-blue, respectively. Secondary confirmation involves treatment of the exhibit with dilute aqueous hydrochloric acid and formation of a deep blue colour.

The rhodizonate test is not specific to lead (it can detect the presence of both barium and cadmium) and is always performed after a test for nitrites (see GRIESS test - 14th February 2013).