NCJ Number
145756
Journal
Journal of Forensic Sciences Volume: 38 Issue: 4 Dated: (July 1993) Pages: 864-873
Date Published
1993
Length
10 pages
Annotation
This article describes three experimental studies of thin layer chromatography (TLC) techniques used in forensic explosive investigations at the Royal Armament Research and Development Establishment in Woolwich, England.
Abstract
TLC plates were used as supplied without activation, and solutions were applied to the plates using disposable glass micropipettes. Elution was carried out vertically in unlined glass tanks, with visualization reagents applied using commercial aerosol sprays. After visualization was complete, plates were kept in clear nylon bags. The first study demonstrated that 200 ng amounts of nitroglycerine (NG) and pentaerythritol tetranitrate (PETN) in TLC spots, visualized using the sodium hydroxide/Griess system, can be recovered and analyzed using a second TLC eluent. The second study investigated the characteristics of a titanium(III) chloride/4-dimethylaminobenzaldehyde visualization system for nitrotoluenes. It found that TLC visualization using this system is slow unless heat is applied and that the application of heat speeds spot development and enhances sensitivity. The third study showed that, under certain conditions, the rate of PETN spot color development after Griess reagent spray can be slow in comparison with that of NG. 6 references, 5 tables, and 4 figures