Volume 24, Issue 3 (July 1979)
Spot Tests: A Color Chart Reference for Forensic Chemists
Spot tests, the most common of preliminary screening tests, have been of long-standing use in forensic analysis. With the advent of technological instrumentation, the importance of this utilitarian, albeit basic, test procedure has diminished. In the early development of currently accepted laboratory technique, the spot test (also referred to as the color test) was often employed as a conclusive method for substance identification. Advanced technology has demonstrated that color tests alone indicate nothing but the possible presence or absence of a particular molecular grouping. Consequently, the color test must be considered inconclusive for purposes of positive identification. Thus the main purpose of the spot test is to narrow the list of substances possibly present in any given unknown.