Letters minimize erroneous conclusions that could arise as a result of Asplund's communication. We agree with Asplund that there may be additional constituents in gunpowder such as the phthalates, urethanes, and nitrosodiphenylamines. This is well-known and docu mented in the literature (2). In normal gunpowders and firearm discharges, these constituents are present in very small amounts so as to make their de tection extremely difficult (2, 3). Most of these constituents that Asplund lists are also so widespread as to make their detection meaningless in a foren sic situation. Asplund apparently is concerned with accelerated aging studies of gunpowder, which is an en tirely different situation than that en countered in normal firearm dis charges. It is true that the nitrosodiphenylamines and related degradation products can be detected occasionally in a firearm residue. We also report such information in an article on gun shot residue determinations in the April issue of the Microchemical Journal. The article on which As plund commented gives in general form our thoughts and results on the problem described—the detection of
black powder or smokeless powder in a firearm residue. As stated, it is a summary of a presentation given at a Benedetti-Pichler Symposium. It does not report the conditions for the anal ysis in the detailed manner of a re search article, and it should not be read as such. For example, we did not include the composition of the mobile phase (presently we are using a 52% acetonitrile, 1% triethylamine, 1% phosphoric acid, and 46% water solu tion). Such information as well as ad ditional experimental information would be contained in a research arti cle, but it is not appropriate for the type of article we wrote. We wish to emphatically point out and clear up a possible major misun derstanding. We have never stated that the appearance of a chromato graphic peak by itself under condi tions where diphenylamine is detected can be considered as totally unambig uous and conclusive proof of the pres ence of smokeless powder. We have assiduously refrained from such rea soning and thought that we went into sufficient, extensive considerations to prevent any reader from coming to such a conclusion. This is why we went into the explanation for multiple test
ings and the need for description of the conditions such as the injured shooter and the damaged firearm so as to overcome reasonable-doubt argu ments. Chromatography is a separa tion method, not an absolute method of identification. Only under properly selected conditions can a chromato graphic separation be very persuasive for identification purposes. Again we appreciate Asplund's com ments, although we think they are not pertinent and are actually misleading. Because of future forensic implica tions, we are pleased to be able to offer this additional written commentary so as to hopefully prevent such questions from re-arising. Darwin B. Dahl and Peter F. Lott Chemistry Department University of Missouri—Kansas City Kansas City, Mo. 64110 References
(1) Yinon, J.; Zitrin, S. "The Analysis of Explosives"; Pergamon Press: New York, N.Y., 1981. (2) Mach, M. H.; Pallos, Α.; Jones, P. F. J. Forensic Sci. 1978,23, 446-55. (3) Bratin, K; Briner, R. C; Bruntlet, C. S.; Kissinger, P. T. Anal. Chim. Acta 1981,110, 295-311.
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ANALYTICAL CHEMISTRY, VOL. 57, NO. 8, JULY 1985 · 867 A
