NCJ Number
131256
Journal
Journal of Forensic Sciences Volume: 36 Issue: 4 Dated: (July 1991) Pages: 1094-1101
Date Published
1991
Length
8 pages
Annotation
A numerical system for encoding color reactions on thin layer chromatography (TLC) plates was developed in order to enhance the toxic substance identification power (IP) of TLC by combining it with the retardation factor (Rf) values and making it amenable to computer handling.
Abstract
The system is based on a series of four color reactions performed in sequence on the same TLC plate. The observed color was encoded according to a wheel of reference colors. The combined information of the Rf values plus color reactions produced an 8-fold increase in IP in comparison with the information provided by the Rf values alone. A comparison of TLC with gas chromatography (GC) revealed that a single TLC system with the four color stages provides a 3- to 4-times higher IP than the standard GC system on OV-1/SE 30. Moreover, the IP of TLC can be enhanced even further by using two or more systems in parallel, especially when the systems chosen have little correlation. GC, however, does not offer this additional advantage since all its systems are highly correlated. Another important feature of the use of a color encoding wheel is the ease and speed of operation. 3 tables and 8 references (Author abstract modified)