NCJ Number
145916
Journal
Journal of Forensic Sciences Volume: 38 Issue: 6 Dated: (November 1993) Pages: 1502-1506
Date Published
1993
Length
5 pages
Annotation
This article describes the use of a modified reagent for the confirmation of blood that makes the test faster and easier.
Abstract
Oxygen and pyridine compete for the same binding site on the heme molecule. Lowering the oxygen concentration in Takayama's reagent by addition of an oxygen scavenger such as dithiothereitol (Cleland's reagent) shifts this equilibrium in favor of pyridine and increases the rate at which hemochromogen crystals are formed. The chemically modified reagent contains 120 ml of Cleland's reagent (0.05 M dithiothreitol), 50 ml NaOH, 50 ml of saturated dextrose solution, and 50 ml of pyridine. This chemically modified reagent remains "oxygen free" in the presence of atmospheric oxygen until the dithiothreitol is consumed. Takayama's reagent from hemochromogen crystals from dried blood stains faster without oxygen. Heat is not required to initiate this crystallization. This makes the oxygen-free reagent more convenient to use. It is also better for the analysis of small or dilute blood stains, where diffusion losses incident to long incubation or heat induced fluid movements can reduce heme concentrations enough to prevent crystallization. 1 table, 1 figure, and 7 references