Published:Journal of Chromatographic Science,
ISSN 0021-9665 Volume
45, Number 6, July 2007, pp.345-349
Identification of Spontaneous Conversion Products
of Unstable 2,4,6-Trinitrotoluene Metabolites, Hydroxylamino-dinitrotoluenes,
by Combination of Thin-Layer Chromatography and Laser Time-of-Flight
Mass Spectrometry
Toshinari Maeda[1], Nobuaki Nagafuchi[1], Akira
Kubota[1], Kiwao Kadokami[1,2], and Hiroaki I. Ogawa[1],
[1]Department of Biological Functions and Engineering, Graduate
School of Life Science and Systems Engineering, Kyushu Institute
of Technology, 2-4 Hibikino,Wakamatsu-ku, Kitakyushu 808-0196,
Japan and
[2]Aqua Research Center, Graduate School of Environmental Engineering,
The University of Kitakyushu, 1-2-1 Shinike, Tobata-ku, Kitakyushu
804-0082, Japan
Two kinds of hydroxylamino-dinitrotoluenes, 2-hydroxylamino-4,
6-dinitrotoluene (2HADNT) and 4-hydroxylamino-2, 6-dinitrotoluene
(4HADNT), are known to be major metabolites produced from 2,4,6-trinitrotoluene
(TNT) by bacteria. The amounts of 2HADNT and 4HADNT in distilled
water are found to spontaneously decrease with time, albeit abiotic
conditions, and many white precipitates are educed in the processes
of this phenomenon; however, how these compounds are converted
is unclear. We evinced the mystery of this phenomenon by using
thin-layer chromatography (TLC) and laser time-of-flight mass
spectrometry (TOFMS). TLC analyses in the spontaneous conversion
processes of 2HADNT, 4HADNT, and 2HADNT plus 4HADNT demonstrats
that three novel spots emerge on the TLC plate, respectively.
These products are individually extracted into acetonitrile by
collecting each spot. The purity of these extracts, which have
retention times of 14.0, 17.7, and 15.4 min, is approximately
98%, judging from the results of high-performance liquid chromatographic
analyses. The spontaneous conversion products of 2HADNT, 4HADNT,
and 2HADNT plus 4HADNT are identified as 4,4’,6,6’-tetranitro-2,2’-azoxytoluene
(2,2’AZT), 2,2’,6,6’-tetranitro-4,4’-azoxytoluene
(4,4’AZT), and 4,2’,6, 6’-tetranitro-2,4’-azoxytoluene
(2,4’AZT) by obtaining their mass spectra with laser TOFMS.
It is confirmed that most of the spontaneous conversion products
are 2,2’AZT, 4,4’AZT, or 2,4’AZT, judging from
the results of mass balance in the spontaneous conversion processes
of 2HADNT, 4HADNT, and 2HADNT plus 4HADNT.
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