RESUMO
Infrared spectra (4000-250 cm-1) of the liquid, amorphous, crystalline solids and solutions in liquid krypton and Raman spectra (2500-20 cm-1) of the liquid as well as the amorphous and crystalline solids of ethylbenzene and its deuterated analogue-ethylbenzene-d(10) have been recorded. The spectra indicate that in the liquid and amorphous solids a small amount of a second conformer is present, whereas only one conformer remains in the crystalline phases. Assignments of the observed band wave numbers are discussed by comparison with normal mode wave numbers and IR and RS intensities calculated from ab initio 6-31G force fields and optimised geometries for both conformers for two species. All of the normal modes of conformers have been assigned.
Assuntos
Derivados de Benzeno/química , Espectrofotometria Infravermelho/métodos , Criptônio , Conformação Molecular , Distribuição Normal , Análise Espectral Raman , TemperaturaRESUMO
The dependence of the mutagenic potential of 2,4,6-trinitrotoluene (TNT) on the growth phase of the Salmonella typhimurium tester strains TA100 and TA98 is shown. The mutagenic potential proved to be maximal for log-phase cultures, being higher with strain TA100 than TA98. The amount of TNT absorbed by bacteria in the first minutes of contact varied, depending on culture age, and was the largest at the beginning of the exponential growth phase. A direct relation between the number of microbial cells and the amount of TNT absorbed from the medium was shown. The analysis of infrared (IR) spectra of cells after a 3-min contact with TNT, demonstrated that, at physiological temperatures, 2.4% of the original amount of TNT was present in cells of the tester strain in an unaltered form, while, at a lowered temperature, this value was 10.3%. Thus, the retardation of physiological processes in the cell changes the intensity of mutagen absorption and transformation. It is emphasized that an accurate assessment of mutagenicity should take into account the physiological state of tester bacteria.
