A test protocol for evaluating trace explosives detectors was assessed in a laboratory setting with a nonspecialist to determine its usefulness for law enforcement personnel with an interest in detection of drugs or explosives but without the training or background of specialists.
The test protocol was contained in NIJ Guide 100-99, titled "A Guide for Selection of Commercial Explosives Detection Systems" for Law Enforcement Applications and was developed at Sandia National Laboratories in fiscal year 1998. The test protocol gave the essential steps of operating a trace chemical analyzer, preparing samples, maintaining records of measurements, and interpreting the results. The protocol was written to be as generic as possible. The assessment focused on discovering flaws or pragmatic barriers to the application of the test protocol, both in the written descriptions of principles and in the procedures provided to evaluate trace detectors. A nonspecialist with an undergraduate education in chemistry made the tests to determine if the proposed methods were realistic, clearly presented, and technically sound. The nonspecialist prepared stock solutions for TNT, RDX, and PETN for use on a commercial detector, the Itemiser from Ion Track Instruments, Inc. Results suggested that analyzers that come to a user from uncertain conditions of use or storage should be assessed to ensure performance as designed and delivered originally. Results also suggested the need for an added page of cautions in the test protocol. Overall, findings indicated that the test protocol was realistic and usable by a nonspecialist in ion mobility spectrometry analyzers, although with a bachelor's degree in chemistry. Thus, the test protocol is a reasonable attempt to bring order to the comparison of trace detector evaluations. Figures, list of symbols and abbreviations, and appended discussion of the Itemiser and ion mobility spectrometry